Micro-optics for optical imager with non-uniform filter

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p . 138 Illus . , 85 Illus . In color. , Hardcover ISBN 978-3-642-27522 7 , 2013 . * cited by examiner

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User Interface 115

Passive Light Capturing Device 102 System Controller 104

Processor Memory

Light Sensing Module

Processor Memory

Light Detection

System 112

Optical Sensing

System 110

Optical

Components 116

Bulk Receiver

Optic 114

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Light Detection

System 200

Bulk receiver Micro -Optic Rx Optic Aperture 202 Layer 211 Layer 204 Light Cone

Optic Rx

Channel

XXX

L"AL ANA

Apertures

206 Collimating 216 Lenses 214

Optical

Filter 218

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User Interface 415

Light Ranging Device 402

Ranging System Controller 404

Electric

Light Sensing Module ( Rx ) Light Transmission (Tx )

Processor Memory Processor Memory 3

422 424 418 420 $

Rx Optical System Tx Optical System

Light Detection Light Emission System 436 System 438

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Initialize coded -pulse optical 900 910 system ( CPOS ) with parameters for coding pulses

Pause as needed and transmit 920 pulse train according to a pulse code

930 Start optical detection

Added weighted data values ( e.g. , 940 intensities of detected pulses to histogram

No Yes Determine histogram A All pulses sent corresponding to the weighted values in a plurality of time bins

Detect a signal corresponding to 970 the N pulse trains using the 990 histogram

No Stop Command Determine distance to object using

Received ? matched part of histogram

Stop measuring distances

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MICRO - OPTICS FOR OPTICAL IMAGER represent a different wavelength of light compared to the WITH NON - UNIFORM FILTER pixels at the scene extremities. A wide field - of -view is desirable for some applications because it provides better

CROSS REFERENCES TO RELATED situational awareness . For example, a camera -based auto APPLICATIONS 5 motive safety system meant to detect pedestrians around a vehicle might require monitoring in a 360 degree field -of

This application claims priority to U.S. Provisional Patent view around the vehicle . Fewer wide field -of - view sensors Application No. 62 / 506,449 , filed on May 15 , 2017 , U.S. are required to do the same job (i.e. , generate images of the Provisional Patent Application No. 62 / 506,437 , filed on May full 360 degree field -of - view ) as many narrow field of view 15 , 2017 , U.S. Provisional Patent Application No. 62/506 , 10 sensors, thereby decreasing the system cost. 445 , filed on May 15 , 2017 , and U.S. Provisional Patent Narrowband imagers have many applications including Application No. 62/ 515,291 , filed Jun . 5 , 2017 , the disclo- geographic mapping, astronomy and in LIDAR ( Light sures of which are herein incorporated by reference in their Detection and Ranging ). Narrowband imagers can detect entirety and for all purposes . characteristic light wavelengths such as those generated by 15 plants with chlorophyll or by elements within stars. Nar

BACKGROUND rowband imagers can be used , for example, to determine vegetation health or to discover oil deposits. Optical receiver

An imager detects light and creates a digital image of a systems , such as LIDAR, can be used for object detection scene based on that detected light. The image contains a and ranging. LIDAR systems measure the distance to a fixed number of rows and columns of pixels where each 20 target or objects in a landscape, by irradiating a target or pixel maps to a different field -of - view within the scene . landscape with light, using pulses from a laser, and measur Electronic imagers typically make use of photodetectors to ing the time it takes photons to travel to the target or convert light into electrical signals . Each photodetector is landscape and return after reflection to a narrowband imager. located at a different position on the focal plane and usually Other LIDAR techniques, such as photo -demodulation , corresponds to a single pixel or a component of a pixel in the 25 coherent LIDAR, and range-gated LIDAR , also rely on the image . Electronic imagers can typically be classified as one transmission and reflection of photons , though they may not of two types: a passive -illumination imager or an active- directly measure the time -of -flight of pulses of laser light. illumination imager. A passive - illumination imager collects For many LIDAR applications, it is beneficial for physical ambient light such as sunlight reflected by objects in a scene, sizes of transmitters and receivers to small and compact, and whereas an active - illumination imager illuminates the scene 30 at the same time relatively low in cost . For applications and collects reflected light generated by the active - illumi- where objects must be sensed with accuracy at long dis nation imager system itself. tances , it is beneficial to increase or maximize the number of A narrowband imager collects light within a limited photons emitted by the transmitter and reflected back toward wavelength range . This is in contrast to a traditional camera the receiver while keeping laser energy emissions within which detects light across the entire visible spectrum or into 35 mandated safety limits .

three different wide , RGB color bands , each of which may Micro -optical systems are systems that include miniatur be 100 nm or wider. Narrowband imagers are harder to ized, optical components that are typically between a few develop than traditional cameras due to the characteristics of micrometers and a millimeter in size . Micro -optical receiv the optical filters on which they rely. Optical filters serve to ers arrayed adjacent to each other are susceptible to cross prevent some portion of the electromagnetic spectrum from 40 talk . Stray light caused by roughness of optical surfaces, reaching the photodetectors. Most narrowband filters rely on imperfections in transparent media , back reflections, etc. , thin - film interference effects to selectively transmit or reflect may be generated at various features within the receiver light ( such filters are often referred to as dielectric mirrors or channel or external to receiver channel. When multiple Bragg mirrors ). The spectral transmissivity of the narrow- receiver channels are arrayed adjacent to one another, this band filter depends on the number, thicknesses, ordering, 45 stray light in one receiver channel may be absorbed by a and indices of refraction of the constituent layers forming photosensor in another channel, thereby contaminating the the filter. The spectral transmissivity of the filter also timing , phase, or other information inherent to photons . depends upon the angle of incidence of the light upon the Minimizing crosstalk is especially important in active- illu narrowband filter . mination systems . Light reflected from a nearby retro Current narrowband imagers have either aa small field -of- 50 reflector (e.g. a license plate ) may be thousands or millions view or are limited in their ability to filter wavelength bands of time more intense than light reflected from a distant, dark , narrower than around 50 nm . Optical filters are sensitive to lambertian surface (e.g. black cotton clothing ). Thus, the ? the angle of incident light making it difficult to achieve a stray light photons from a retro -reflector could vastly out narrow range of wavelengths. For example, an optical filter number photons reflected from other surfaces in nearby may accept perpendicular light with wavelength at 940-945 55 photosensors if crosstalk is not minimized . This can result in nm and slightly oblique light at a wavelength of 930-935 the inability of a LIDAR system to detect dark objects that nm . Since most photodetectors in a traditional camera have occupy fields of view near the field of view occupied by a a large range of angles of light incident upon them , simply retro - reflector.

placing an optical filter in front of them would not actually achieve narrowband filtering . Constricting the angle of light 60 SUMMARY incident upon the photodetector usually requires using a lens with a longer focal length , which constricts the field -of - view Embodiments of the disclosure provide optical imager of the camera . systems that achieve wide field -of -view , narrowband imag Imagers with a wide field -of - view have difficulty in ing with micro - optic receiver channel arrays that minimize generating uniformly clear visual images and in making 65 crosstalk and allow tight spectral selectivity that is uniform uniform measurements across a scene . For example, the across the receiver channel array. Some optical imager pixels at the center of the image may appear brighter or systems according to the disclosure can include a light

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transmission module that provides enhanced spot illumina- mitter optic , and the micro -optic channel array can define a tion such that a power level of light returning to a light plurality of micro -optic channels where each micro -optic sensing module is increased , while at the same time improv- channel can include aa micro -optic lens spaced apart from a ing the spatial resolution of the measured image . light emitter from the plurality of light emitters with the In some embodiments, an optical system for performing 5 micro -optic lens being configured to receive a light cone distance measurements includes a bulk transmitter optic , an from the light emitter and generate a reduced -size spot illumination source, and a micro - optic channel array dis image of the emitter at a focal point displaced from the posed between the illumination source and the bulk trans emitter at a location between the emitter and the bulk mitter optic . The illumination source includes a plurality of transmitter optic.

light emitters aligned to project discrete beams of light 10 In some embodiments , an optical system includes aa bulk through the bulk transmitter optic into a field ahead of the receiver optic configured to receive light rays originating optical system . The micro -optic channel array defines a from a field external to the optical system , and an optical plurality of micro - optic channels where each micro -optic assembly having a plurality ofmicro - optic receiver channels channel includes a micro -optic lens spaced apart from a light emitter from the plurality of light emitters with the micro- 15 view defining a plurality of discrete, non -overlapping fields of optic lens being configured to receive a light cone from the layer inhaving the field . The optical assembly includes an aperture a plurality of discrete apertures arranged along light emitter and generate a reduced - size spot image of the emitter at a focal point displaced from the emitter at a a focal plane of the bulk receiver optic , an array of photo location between the emitter and the bulk transmitter optic . sensors disposed behind the aperture layer, and a non The micro -optic lens for each channel can be configured to 20 uniform optical filter layer configured to allow different receive a light cone from a light emitter and generate a micro - optic channels to measure different ranges of wave reduced - size real spot image of the emitter at a focal point lengths. The non - uniform optical filter can include a gradu between the micro -optic lens and the bulk transmitter optic . ated optical filter that gradually increases in thickness in one A divergence of the light cone from the light emitter can be dimension , or increases in thickness in a step -wise fashion less than a divergence of a light cone from the second optical 25 in one direction such that each channel has a constant optical surface of the micro -optic lens for generating the reduced- filter layer thickness, but where the thicknesses for different size real spot image micro - optic channels are different. In some additional embodiments, an optical system for In some additional embodiments, an optical system performing distance measurements includes a light emission includes a bulk receiver optic configured to receive light system and a light detection system . The light emission 30 from aa field external to the optical system , an aperture layer system includes a bulk transmitter optic , an illumination disposed behind the bulk optic and including a plurality of source comprising a plurality of light emitters aligned to apertures located at a focal plane of the bulk optic , a lens project discrete beams of light through the bulk transmitter layer including a plurality of collimating lenses having a optic into a field ahead of the optical system , and aa micro- focal length , the lens layer disposed behind the aperture optic channel array disposed between the illumination 35 layer and separated from the aperture layer by the focal source and the bulk transmitter optic . The micro -optic length , a non - uniform optical filter layer behind the lens channel array defines a plurality of micro -optic channels layer, and a photosensor layer including a plurality of where each micro -optic channel includes aa micro - optic lens photosensors. The aperture layer, lens layer, non - uniform spaced apart from a light emitter from the plurality of light optical filter layer and photosensor layer are arranged to emitters with the micro -optic lens being configured to 40 form a plurality of micro -optic channels defining a plurality receive a light cone from the light emitter and generate a of discrete , non -overlapping fields of view in the field with reduced - size spot image of the emitter at a focal point each micro -optic channel in the plurality of micro -optic displaced from the emitter at aa location between the emitter channels including an aperture from the plurality of aper and the bulk transmitter optic . The light detection system tures, a lens from the plurality of lenses , a filter from the includes a bulk receiver optic configured to receive the 45 filter layer, and a photosensor from the plurality of photo discrete beams of light from the field , and an optical sensors and being configured to communicate light incident assembly having a plurality of micro - optic receiver channels from the bulk receiver optic to the photosensor of the defining a plurality of discrete, non -overlapping fields of micro - optic channel. The non -uniform optical filter layer is view in the field . The optical assembly includes: an aperture configured to allow different micro - optic channels to mea layer having a plurality of discrete apertures arranged along 50 sure different ranges of wavelengths. a focal plane of the bulk receiver optic ; an array of photo- In certain embodiments, an optical system includes a bulk sensors disposed behind the aperture layer; and a plurality of receiver optic configured to receive light rays originating lenses positioned between the aperture layer and the array of from a field external to the optical system , and an optical photosensors. assembly having a plurality of micro - optic receiver channels In certain embodiments, an optical system for performing 55 defining a plurality of discrete , non -overlapping fields of distance measurements includes a stationary housing having view in the field . The optical assembly includes a monolithic an optically transparent window , and a light ranging device ASIC including a processor, a memory , and a plurality of disposed within the housing. The light ranging device photosensors fabricated in the ASIC , an aperture layer includes an optical transmitter coupled to a platform . The having a plurality of discrete apertures arranged along a optical transmitter includes a bulk transmitter optic , an 60 focal plane of the bulk receiver optic , the array of photo illumination source , and a micro -optic channel array dis- sensors disposed behind the aperture layer ; a plurality of posed between the illumination source and the bulk trans- lenses positioned between the aperture layer and the array of mitter optic . The illumination source including a plurality of photosensors; and a non - uniform optical filter layer having light emitters aligned to project discrete beams of light different center wavelengths across its structure to allow at through the bulk transmitter optic into a field ahead of the 65 least two different micro - optic receiver channels to measure optical system . The micro -optic channel array can be dis- different ranges of wavelengths of light, wherein the aper posed between the illumination source and the bulk trans- ture layer, plurality of lenses, and non - uniform optical filter

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layer are formed on the ASIC such that they form part of the VCSELs are configured to generate and transmit discrete monolithic structure of the ASIC . pulses of light into a field external to the optical system . The In some embodiments, an optical system for performing optical receiver including a bulk receiver optic , a plurality of distance measurements includes a stationary housing having photosensors, each photosensor comprising a plurality of an optically transparent window , a spinning light ranging 5 single -photon avalanche diodes ( SPADs) responsive to inci device disposed within the housing , a motor disposed within dent photons, and an optical filter disposed between the bulk the housing and operatively coupled to spin the light ranging receiver optic and the plurality of photosensors and config device including the platform , optical transmitter, and opti- ured to allow aa band of light to pass through the filter to the cal receiver within the housing , and a system controller plurality of photosensors while blocking light outside the disposed within the housing , the system controller config- 10 band from reaching the plurality of photosensors . ured to control the motor and to start and stop light detection In some embodiments , an optical system for performing operations of the light ranging device . The light ranging distance measurements includes a rotatable platform , an device includes a platform , an optical transmitter coupled to optical transmitter coupled to the rotatable platform and the platform , and an optical receiver coupled to the platform . comprising a bulk transmitter optic and a plurality of trans The optical transmitter includes aa bulk transmitter optic and 15 mitter channels, an optical receiver coupled to the rotatable a plurality of transmitter channels, each transmitter channel platform and comprising a bulk receiver optic and a plurality including a light emitter configured to generate and transmit of micro - optic receiver channels, a motor disposed within a narrowband light through the bulk transmitter optic into a the housing and operatively coupled to spin the platform , field external to the optical system . The optical receiver optical transmitter, and optical receiver, a system controller includes a bulk receiver optic and a plurality of micro -optic 20 mounted to a stationary component of the optical system ;

receiver channels, each micro - optic channel including an and an optical communication link operatively coupled aperture coincident with a focal plane of the bulk receiver between the system controller and the optical receiver to optic , an optical filter positioned along a path of light from enable the system controller to communicate with the optical the bulk receiver optic and axially aligned with the aperture , receiver. Each transmitter channel includes a light emitter and a photosensor responsive to incident photons passed 25 configured to generate and transmit a narrowband light through the aperture and the optical filter. through the bulk transmitter optic into aa field external to the In some additional embodiments, an optical system for optical system . Each micro -optic channel includes an aper performing distance measurements includes a stationary ture coincident with aa focal plane of the bulk receiver optic , housing having a base , a top and an optically transparent an optical filter positioned along a path of light from the bulk window disposed between the base and the top , a spinning 30 receiver optic and axially aligned with the aperture , and a light ranging device disposed within the housing and aligned photosensor responsive to incident photons passed through with the optically transparent window , a motor disposed the aperture and through the filter. The optical communica within the housing and operatively coupled to spin the light tion link can extend between the stationary component of the ranging device including the platform , optical transmitter optical system and the rotatable platform to operatively and optical receiver within the housing , and a system 35 couple the system controller with the optical receiver. The controller disposed within the housing, the system controller optical receiver can further include a collimating lens behind configured to control the motor and to start and stop light the aperture and directly coupled to the optical filter, the detection operations of the light ranging device . The light optical filter positioned behind the collimating lens. ranging device including a platform , an optical transmitter In some additional embodiments, an optical system for coupled to the platform , and an optical receiver coupled to 40 performing distance measurements including a rotatable the platform . The optical transmitter including an image- platform , an optical transmitter coupled to the rotatable space telecentric bulk transmitter optic and a plurality of platform and comprising an image - space telecentric bulk transmitter channels, each channel including a light emitter transmitter optic and a plurality of transmitter channels, an configured to generate and transmit a narrowband light optical receiver coupled to the rotatable platform and com through the bulk transmitter optic into aa field external to the 45 prising an image - space telecentric bulk receiver optic and a optical system . The optical receiver including an image- plurality of micro - optic receiver channels, a motor disposed space telecentric bulk receiver optic and a plurality of within the housing and operatively coupled to spin the micro - optic receiver channels, each micro -optic channel platform , optical transmitter and optical receiver, a system including an aperture coincident with a focal plane of the controller mounted to a stationary component of the optical bulk receiver optic , a collimating lens behind the aperture, 50 system , and an optical communication link operatively an optical filter behind the collimating lens and a photosen- coupled between the system controller and the optical sor responsive to incident photons passed through the aper- receiver to enable the system controller to communicate ture into the collimating lens and through the filter. with the optical receiver. Each transmitter channel includes In certain embodiments , an optical system for performing a light emitter configured to generate and transmit nar distance measurements includes aa stationary housing having 55 rowband light through the bulk transmitter optic into aa field a base , a top and an optically transparent window disposed external to the optical system . Each micro -optic channel between the base and the top , a light ranging device disposed includes an aperture coincident with aa focal plane of the bulk within the housing and aligned with the optically transparent receiver optic , a collimating lens behind the aperture , an window , a motor disposed within the housing and opera- optical filter behind the collimating lens and a photosensor tively coupled to spin the light ranging device within the 60 responsive to incident photons passed through the aperture housing ; and a system controller disposed within the hous- into the collimating lens and through the filter. ing , the system controller configured to control the motor In certain embodiments, An optical system for performing and to start and stop light detection operations of the light distance measurements includes a rotatable platform , a plu ranging device. The light ranging device includes a plat- rality of vertical - cavity surface emitting lasers (VCSELS ) form , a plurality of vertical - cavity surface emitting lasers 65 arranged in an array and coupled to the rotatable platform , (VCSELs ) arranged in an array, and an optical receiver an optical receiver coupled to the rotatable platform , a motor coupled to the platform . Each VCSEL in the plurality of disposed within the housing and operatively coupled to spin

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the platform , the plurality of VCSELs and the optical and operatively coupled to spin the light ranging device receiver ; a system controller mounted to a stationary com- including the platform , optical transmitter, and optical ponent of the optical system , and an optical communication receiver within the housing , and a system controller dis link operatively coupled between the system controller and posed within the housing. The system controller configured the optical receiver to enable the system controller to 5 to control the motor and to start and stop light detection communicate with the optical receiver. Each VCSEL in the operations of the light ranging device. The light ranging plurality of VCSELs are configured to generate and transmit device including a platform , an optical transmitter coupled discrete pulses of light into a field external to the optical to the platform , an optical receiver coupled to the platform . system . The optical receiver including a bulk receiver optic and a plurality of photosensors, each photosensor compris- 10 aThe optical transmitter including a bulk transmitter optic and ing a plurality of single -photon avalanche diodes (SPADs) including aoflight plurality transmitter channels, each transmitter channel emitter configured to generate and transmit responsive to incident photons.

In some embodiments , an optical system for performing a narrowband light through the bulk transmitter optic into a distance measurements includes a bulk receiver optic , an field external to the optical system . The optical receiver aperture layer including a plurality of apertures, a first lens is including a bulk receiver optic, an aperture layer including layer including a first plurality of lenses , an optical filter a plurality of apertures, a first lens layer including a first layer configured to receive light after it passes through the plurality of lenses, an optical filter layer configured to bulk receiver optic and pass a band of radiation while receive light after it passes through the bulk receiver optic blocking radiation outside the band , and a photosensor layer and pass a band of radiation while blocking radiation outside including a plurality of photosensors , Each photosensor 20 the band , and a photosensor layer including a plurality of includes a plurality of photodetectors configured to detect photosensors. Each photosensor includes a plurality of pho photons , and a second plurality of lenses configured to focus todetectors configured to detect photons, and a second incident photons received at the photosensor on the plurality plurality of lenses configured to focus incident photons of photodetectors. The optical system includes a plurality of received at the photosensor on the plurality of photodetec receiver channels with each receiver channel in the plurality 25 tors . The optical system includes a plurality of receiver of receiver channels including an aperture from the plurality channels with each receiver channel in the plurality of of apertures, a lens from the plurality of first lenses , an receiver channels including an aperture from the plurality of optical filter from the optical filter layer, and a photosensor apertures, a lens from the plurality of first lenses , an optical from the plurality of photosensors , with the aperture for each filter from the optical filter layer, and a photosensor from the channel defining a discrete , non -overlapping field of view 30 plurality of photosensors, with the aperture for each channel for its respective channel. For each receiver channel in the defining a discrete , non -overlapping field of view for its plurality of receiver channels, there can be a one - to - one respective channel.

correspondence between the plurality of photodetectors and A better understanding of the nature and advantages of the second plurality of lenses in the photosensor for that embodiments of the present disclosure may be gained with channel, where each of the lenses in the second plurality of 35 reference to the following detailed description and the lenses can be configured to focus photons on its correspond- accompanying drawings.

ing lens in the second plurality of lenses

In some additional embodiments, an optical system for BRIEF DESCRIPTION OF THE DRAWINGS performing distance measurements includes a light emission system and a light detection system . The light emission 40 FIG . 1 is aa block diagram of an exemplary passive optical system including a bulk transmitter optic and an illumination imager system , according to some embodiments of the source . The illumination source including a plurality of light present disclosure.

emitters aligned to project discrete beams of light through FIG . 2 is a simplified diagram of an exemplary light the bulk transmitter optic into a field ahead of the optical detection system for a passive optical imager system , system . The light detection system including a bulk receiver 45 according to some embodiments of the present disclosure . optic , an aperture layer including a plurality of apertures, a FIGS . 3A and 3B are perspective views of a simplified first lens layer including a first plurality of lenses , an optical diagram of different embodiments of micro - optic receiver filter layer configured to receive light after it passes through layers with graduated filter layers, according to some the bulk receiver optic and pass a band of radiation while embodiments of the present disclosure.

blocking radiation outside the band , and a photosensor layer 50 FIG . 4 is a block diagram of a rotating LIDAR system , including a plurality of photosensors. Each photosensor according to some embodiments of the present disclosure . includes a plurality of photodetectors configured to detect FIGS . 5A - 5B are simple illustrations of exemplary imple photons , and a second plurality of lenses configured to focus mentations of solid state LIDAR systems , according to some incident photons received at the photosensor on the plurality embodiments of the present disclosure . of photodetectors. The optical system includes a plurality of 55 FIG . 6A - 6B are simple illustrations of exemplary imple receiver channels with each receiver channel in the plurality mentations of scanning LIDAR systems , according to some of receiver channels including an aperture from the plurality embodiments of the present disclosure . of apertures, a lens from the plurality of first lenses , an FIG . 7 is an exemplary perspective view diagram showing optical filter from the optical filter layer, and a photosensor an embodiment of a LIDAR system employing a 360 from the plurality of photosensors , with the aperture for each 60 scanning architecture , according to some embodiments of channel defining a discrete , non - overlapping field of view the present disclosure.

for its respective channel. FIG . 8 is an illustrative example of the light transmission In certain embodiments, an optical system for performing and detection operation for a light ranging system , according distance measurements including a stationary housing hav- to some embodiments of the present disclosure . ing an optically transparent window , a light ranging device 65 FIG . 9 is a flowchart illustrating a method of using coded disposed within the housing and aligned with the optically pulses in an optical measurement system , according to transparent window, a motor disposed within the housing embodiments of the present disclosure .

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FIG . 10 is a simplified diagram illustrating a detailed view module . According to some embodiments of the present

of an exemplary active optical imager system having a wide disclosure, the micro -optic receiver system can include one field - of - view and capable of narrowband imaging , according or more micro - optic receiver layers and one or more pho to some embodiments of the present disclosure . tosensors, each photosensor can include one or more pho FIGS . 11-14 are simplified cross - sectional view diagrams 5 todetectors that can measured received light. of various exemplary enhanced light emission systems, A bulk imaging optic as defined herein can be one or more according to some embodiments of the present disclosure . optical surfaces, possibly including multiple lens elements, FIGS . 15A - 15C are cross - sectional views of simplified diagrams of exemplary active imager systems having dif that have clear apertures greater than one millimeter and that is positioned to receive light projected from , or focus ferent implementations of corrective optical structures for 10 received light on, a micro -optic transmitter / receiver layer. A astigmatism , according to some embodiments of the present bulk imaging optic that projects light received from an disclosure .

FIG . 16A is a simplified cross - sectional view diagram of optical emitter, such as a micro - optic transmitter layer, is sometimes referred to herein as a bulk transmitter optic or as part of a light detection system 1600 where there is no an output bulk imaging optic . A bulk optic layer that focuses cross -talk between channels . 15

FIG . 16B is a simplified cross - sectional view diagram of alight received from a field onto an optical detector, such as part of a light detection system 1601 where there is cross as a bulk- optic micro receiver layer, is sometimes referred to herein receiver optic or as an input bulk imaging optic . An talk between channels.

FIG . 17 is a simplified cross - sectional diagram of an input, image - space telecentric bulk imaging optic allows the exemplary micro - optic receiver channel structure , according 20 system to measure narrowband light uniformly over a wide to some embodiments of the present disclosure . field -of -view ( FOV) . The micro - optic receiver layer can FIGS . 18A - 18D are simplified cross - sectional view dia- include a one- or two - dimensional array of micro -optic grams of various aperture layers for a receiver channel, receiver channels where each micro -optic receiver channel according to some embodiments of the present disclosure . has multiple components including one or more of an FIGS . 19A- 19D are simplified cross-sectional view dia- 25 aperture, a collimating micro -lens , an optical filter, and a grams of various spacer structures between the aperture photosensor. In some instances, the micro -optical receiver layer and the optical lens layer for a receiver channel, channel structure has a columnar arrangement with enclo according to some embodiments of the present disclosure . sures having absorbent and / or reflective side walls and / or FIGS . 20A - 20G are simplified cross - sectional view dia focusing funnels. The micro -optic receiver channel maxi grams of various optical filter layers for a receiver channel, 30 mizes the collection of incoming rays through its aperture, according to some embodiments of the present disclosure . collimates the light to make it perpendicular to the optical FIGS . 21A - 21K are simplified cross - sectional view dia filter, and minimizes crosstalk with adjacent micro -optic grams of various photosensor layers with diffusers for a receiver channels due to mixing of inputs from neighboring receiver channel, according to some embodiments of the 35 apertures, as will be discussed in detail below. In various present disclosure. instances, bulk imaging optics according to the present FIGS . 22A - 221 are simplified cross - sectional view dia disclosure modify light or other radiation for an entire array grams of various hemispherical receiver structures for a receiver channel, according to some embodiments of the included of emitters or photosensors . Micro - optic structures can be present disclosure. as part of the array and can modify light differently FIGS . 23A - 23E are simplified cross -sectional view dia- 40 for different emitters and / or photosensors in the array. In grams of various bottom micro lens layers for a receiver some embodiments, there is one or more micro - optic ele channel, according to some embodiments of the present ments for each individual array element ( photosensor and / or disclosure . emitter ).

FIGS . 24 and 25 are simplified cross - sectional view In some embodiments, the optical imager system can be diagrams of exemplary receiver channels, according to some 45 an active system that can emit light into a field and then embodiments of the present disclosure . detect the emitted light after it has reflected off surfaces of FIGS . 26-30 are simplified top view diagrams of exem- an object in the field . An active optical imager system can plary micro -optical receiver arrays , according to some include a light transmission module in addition to a light embodiments of the present disclosure . sensing module, and be configured as a light ranging device . 50 The light transmission module can include a transmitter

DETAILED DESCRIPTION layer that is composed of an array of individual emitters where each emitter can be paired with a corresponding

Some embodiments of the disclosure pertain to optical micro - optic receiver channel in the light sensing module, or imager systems that can generate an image from ambient it can be a uniform illuminator that spreads light evenly light in a field and / or light emitted from an optical trans- 55 across the scene with no specific pairing between individual mitter that has reflected off of an object in the field . For emitters and receiver channels. In some instances , the light instance, in some embodiments an optical imager system transmission module can include a micro - optic transmitter can be a passive system that does not actively illuminate a channel array to enhance light outputted from the array of scene or given area and instead detects ambient light in the emitters. During operation, light outputted by the array of scene or area reflected off of one or more objects in the scene 60 emitters (e.g. , laser pulses ) passes through the micro -optic or area . A passive optical imager system can include a light transmitter channel array and enters a bulk transmitter optic sensing module for receiving ambient light in the field . The having a large numerical aperture to better capture light from light sensing module can be a wide field -of- view , narrow- the micro -optic transmitter channel array. The light then band optical imaging system (WFNBI ) that collects imaging exits the bulk transmitter optic and illuminates a plurality of information . The light sensing module can include one or 65 spots at a distant field . The micro - optic transmitter channel more bulk receiver optics , a micro - optic receiver system , array can improve the brightness of beams emanating from and a system controller for operating the light sensing the bulk transmitter optic to provide enhanced spot illumi

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nation , while at the same time improving the spatial reso- In such instances , optical components 116 can be formed , lution of the measured image , as will be discussed in detail e.g. , bonded ( non - reversibly) with epoxy, on the ASIC so further herein . that it becomes part of the monolithic structure , as will be According to some embodiments of the present disclo- discussed further below . As mentioned above, processor 118 sure , the imager system is a wide field - of - view , narrowband 5 (e.g. , a digital signal processor (DSP ) , microcontroller, field optical system . Thus, the imager can capture images and programmable gate array ( FPGA ), and the like) and memory detect light across a FOV of at least 10 degrees . In certain 120 (e.g. , SRAM ) can perform the signal processing . As an embodiments, the imager can capture images and detect example of signal processing, for each photosensor or light across a FOV of at least 20 , and across aa FOV of at least grouping of photosensors , memory 120 of light sensing 30 degrees in some embodiments. Furthermore, the imager 10 module 106 can accumulate detected photons over time , and can detect light at a wavelength of approximately 10 nm or these detected photons can be used to recreate an image of less . In some particular embodiments, the light sensing the field .

module can detect light at a wavelength of approximately 5 In some embodiments, the output from processor 118 is nm or less . In some embodiments , the imager system can sent to system controller 104 for further processing, e.g. , the capture detect light at a wavelength of less than 5 nm across 15 data can be encoded by one or more encoders of the system a FOV of approximately 32 degrees. The FOV can be in the controller 104 and then sent as data packets to user interface vertical or horizontal direction, or any other angle in 115. System controller 104 can be realized in multiple ways between . including, e.g. , by using a programmable logic device such To better understand the function and configuration of an FPGA, as an ASIC or part of an ASIC , using a processor passive and active optical imager systems according to 20 122 with memory 124 , and some combination of the above . embodiments of the disclosure, each will be discussed in System controller 104 can cooperate with a stationary base detail herein . controller or operate independently of the base controller I. Passive Optical Imager Systems ( via pre -programmed instructions ) to control light sensing A passive optical imager system receives ambient light to module 106 by sending commands that include start and generate an image . FIG . 1 is a block diagram of an exem- 25 stop light detection and adjust photodetector parameters. In plary passive optical imager system 100 , according to some some embodiments , system controller 104 has one or more embodiments of the present disclosure . Passive optical wired interfaces or connectors for exchanging data with light imager system 100 includes a passive light capturing device sensing module 106. In other embodiments, system control 102 for capturing light existing within aa field . Passive light ler 104 communicates with light sensing module 106 over a capturing device 102 can include a system controller 104 30 wireless interconnect such as an optical communication link . and a light sensing module 106. Imaging data can be Passive optical imager system 100 can interact with a user generated by passive light capturing device 102 by receiving interface 115 , which can be any suitable user interface for light existing in a field in which passive optical imager enabling a user to interact with a computer system , e.g. , a system 100 is positioned . The received light can be light that display, touch - screen , keyboard , mouse , and / or track pad for exists naturally in the field, i.e. , ambient light, as opposed to 35 interfacing with a laptop , tablet, and / or handheld device light emitted from a transmitter within system 100 . computer system containing a CPU and memory. User Light sensing module 106 can include a sensor array 108 , interface 115 may be local to the object upon which passive which can be , e.g. , a one - dimensional or two - dimensional optical imager system 100 is mounted but can also be a array of photosensors . Each photosensor ( also just called a remotely operated system . For example , commands and data “ sensor” or sometimes referred to by one skilled in the art as 40 to / from passive optical imager system 100 can be routed a “ pixel” ) can include a collection of photodetectors, e.g. , through a cellular network ( LTE , etc. ), a personal area SPADs or the like , or a sensor can be a single photon network (Bluetooth , Zigbee , etc. ) , a local area network detector ( e.g. , an APD ) . Light sensing module 106 includes (WiFi, IR , etc. ), or a wide area network such as the Internet. an optical sensing system 110 , which when taken together 2 User interface 115 of hardware and software can present with sensor array 108 can form a light detection system 112. 45 the imager data from the device to the user but can also allow In some embodiments, optical sensing system 110 can a user to control passive optical imager system 100 with one include a bulk receiver optic 114 and optical components or more commands. Example commands can include com 116 , such as an aperture layer, a collimating lens layer and mands that activate or deactivate the imager system , specify an optical filter, that can be combined with sensor array 108 photodetector exposure level , bias , sampling duration and to form an array of micro - optic receiver channels where 50 other operational parameters (e.g. , emitted pulse patterns each micro - optic receiver channel measures light that cor- and signal processing ) , specify light emitters parameters responds to an image pixel in a distinct field of view of the such as brightness. In addition, commands can allow the surrounding field in which system 100 is positioned . Further user to select the method for displaying results. The user details of various embodiments of micro -optic receiver interface can display imager system results which can channels according to the present disclosure are discussed in 55 include, e.g. , a single frame snapshot image, a constantly detail in conjunction with FIGS . 17-30 below . updated video image , and / or a display of other light mea In some embodiments, sensor array 108 of light sensing surements for some or all pixels .

module 106 is fabricated as part of a monolithic device on As mentioned herein , one or more components of optical a single substrate (using , e.g. , CMOS technology ) that sensing system 110 can be part of a monolithic structure with includes both an array of photosensors, a processor 118 , and 60 sensor array 108 , processor 118 , and memory 120. For a memory 120 for signal processing the measured light from example, an aperture layer, collimating lens layer, and an the individual photosensors ( or groups of photosensors ) in optical filter layer of optical components 116 can be stacked the array. The monolithic structure including sensor array over and bonded with epoxy to a semiconductor substrate 108 , processor 118 , and memory 120 can be fabricated as a having multiple ASICs fabricated thereon at the wafer level dedicated ASIC . In some embodiments , optical components 65 before or after dicing . For instance , the optical filter layer 116 can also be a part of the monolithic structure in which can be a thin wafer that is placed against the photosensor sensor array 108 , processor 118 , and memory 120 are a part. layer and then bonded to the photosensor layer to bond the

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optical filter layer with the photosensor layer to have the implemented in optical filter 218. Apertures 210 can serve optical layer form part of the monolithic structure ; the various functions during the operation of light detection collimating lens layer can be injection molded onto the system 200. For instance, apertures 210 can ( 1 ) constrain the optical filter layer ; and, the aperture layer can be formed by pixel FOV so it has tight spatial selectivity despite a large layering a non - transparent substrate on top of a transparent 5 pitch at the photosensor plane, ( 2 ) provide a small point- like substrate or by coating a transparent substrate with an source at the collimating lens's focal plane to achieve tight opaque film . Alternatively, the photosensor layer can be collimation of rays before passing through the filter, where fabricated and diced , and the optical filter layer, collimating better collimation results in a tighter band that can pass lens layer, and the aperture layer can be fabricated and diced . through the filter, and ( 3 ) reject stray light. Each diced photosensor layer and optical layers can then be 10 Optical filter 218 blocks unwanted wavelengths of light. bonded together to form a monolithic structure where each Interference -based filters tend to exhibit strong angle depen monolithic structure includes the photosensor layer, optical dence in their performance. For example, a 1 nm wide filter layer, collimating lens layer, and the aperture layer. By bandpass filter with a center wavelength (CWL ) of 900 nm bonding the layers to the ASIC , the ASIC and the bonded at a zero -degree angle of incidence might have a CWL of layers can form a monolithic structure . The wafer can then 15 898 nm at a fifteen -degree angle of incidence . Imaging be diced into devices, where each device can be paired with systems typically use filters several tens of nanometers wide a respective bulk receiver optic 114 to form light sensing to accommodate this effect, so that the shift in CWL is much module 106. In yet other embodiments, one or more com- smaller than the bandpass width . However, the use of ponents of light sensing module 106 can be external to the micro - optic layer 204 allows all rays to enter optical filter monolithic structure . For example, the aperture layer may be 20 218 at approximately the same angle of incidence , thus implemented as a separate metal sheet with pin - holes. A minimizing the shift in CWL and allowing very tight filters more detailed view of an optical sensing system and a sensor (e.g. less than 10 nm wide ) to be used . Photosensor 216 array according to an embodiment of the disclosure is generates electrical currents or voltages in response to discussed herein with respect to FIG . 2 . incident photons. In some embodiments, optical filter 218 is FIG . 2 is a simplified diagram of an exemplary light 25 uniform across the entire array of micro -optic receiver detection system 200 according to some embodiments of the channels 212 so that each individual micro -optic receiver present disclosure . Light detection system 200 can be rep- channel 212 in the array receives the same range of wave resentative of light detection system 112 discussed above lengths of light.

with respect to FIG . 1. Light detection system 200 can In some embodiments, photosensors 216 are positioned include an optical sensing system and a sensor array. The 30 on a side opposite of collimating lenses 214 so that light rays optical sensing system can include bulk receiver optics , an 206 first pass through collimating lenses 214 and optical aperture layer, a collimating lens layer, and an optical filter filter 218 before exposing on photosensors 216. Each pho layer; and the sensor array can include an array of photo- tosensor 216 can be a plurality of photodetectors, such as a sensors , where each photosensor can include one or more mini-array of multiple single -photon avalanche detectors photodetectors for measuring light. According to some 35 (SPADs). An array of mini- arrays of SPADs can be fabri embodiments, these components operate together to receive cated on a single monolithic chip , thereby simplifying light from a field . For instance, light detection system 200 fabrication . In some alternative embodiments, each photo can include a bulk receiver optic 202 and a micro -optic sensor 216 can be a single photodetector, e.g. , a standard receiver ( Rx) layer 204. During operation , light rays 206 photodiode, an avalanche photodiode, a resonant cavity enter bulk receiver optic 202 from multiple directions and 40 photodiode, or another type of photodetector. gets focused by bulk receiver optic 202 to form light cones In some other embodiments, optical filter 218 is non 208. Micro - optic receiver layer 204 is positioned so that uniform . For example, a graduated filter allows different apertures 210 coincide with the focal plane of bulk receiver micro - optic channels to measure a different range of wave optic 202. In some embodiments, micro - optic receiver layer lengths. In other words, a graduated filter allows different 204 can be a one - dimensional or two - dimensional array of 45 micro - optic channels in an array of micro - optic channels to micro - optic receiver channels 212 , where each micro -optic have different center wavelengths ( CWL ) . A graduated filter receiver channel 212 is formed of a respective aperture 210 , typically gradually changes the range of allowed wave collimating lens 214 , and photosensor 216 positioned along lengths in either one or two dimensions . However, a gradu the same axis in the direction of light flow , e.g. , horizontal ated filter could also encompass a filter where the range of from left to right as shown in FIG . 2. Furthermore , each 50 allowed wavelengths changes rapidly (e.g. , step - wise) in one micro - optic receiver channel 212 can be configured various or both dimensions. The different CWLs for the channels ways to mitigate interference from stray light between can be created in various ways . For instance, the thickness photosensors, as will be discussed further herein . During of the filter can change or the index of refraction can change . operation , each micro -optic receiver channel 212 measures The index of refraction can be changed by modifying the light information for a different pixel (i.e. , position in the 55 filter layer, such as by altering its chemical composition , field ). e.g. , by modifying it to have a non -uniform doping concen

At the focal point of bulk receiver optic 202 , light rays tration . As a result, each channel (or row / column of chan 206 focus and pass through apertures 210 in an aperture nels ) can have an optical filter layer that has a different layer 211 and into respective collimating lenses 214. Each doping concentration, thereby resulting in aa different CWL collimating lens 214 collimates the received light so that the 60 for each channel ( or row / column of channels ) without light rays all enter the optical filter at approximately the having a modified thickness. Rotating a one - dimensional same angle, e.g. , parallel to one another. The aperture and array of micro - optic channels with a graduated optical filter focal length of bulk receiver optic 202 determine the cone allows the system to measure light at different wavelengths angle of respective light rays that come to a focus at aperture for each photosensor. Scanning a two - dimensional array of 210. The aperture size and the focal length of collimating 65 micro optic channels where the graduated filter is changing lenses 214 determine how well - collimated the admitted rays along the direction of the scan allows the passive optic can be , which determines how narrow of a bandpass can be imager system to measure light at multiple wavelengths for

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each position in space , but uses multiple photodetectors in 308 can have a different filter thickness than micro -optic the photosensor to do so . Such optical systems using gradu- receiver channels 306 and 310 and thus detect a different ated filters require synchronization of the photosensor sam- wavelength of light . During a first- time interval, the micro pling so that different wavelength measurements are taken optic receiver channels 304 and 308 measure the intensity of for the same photosensor with the same field -of - view . Imag- 5 a first wavelength of light for two pixels respectively. In ing systems that differentiate between many different wave- some embodiments, the hyperspectral passive optic imager lengths are sometimes referred to as hyperspectral imagers . system moves or rotates the micro - optic receiver layer so A hyperspectral imager often requires that light from the that during a second- time interval, micro - optic receiver wavelengths of interest all be focused in approximately the channels 306 and 310 measure the intensity of a second same plane. This can be achieved by using an achromatic, 10 wavelength of light for the same two pixels respectively. In apochromatic, superachromatic, or similar lens that is other embodiments, a hyperspectral passive optic imager designed to limit the effects of chromatic aberration . system according to the disclosure can include a stationary Hyperspectral imagers collect information from multiple micro - optic receiver layer and scan a moving target. wavelength bands across the electromagnetic spectrum . The II . Active Optical Imager Systems absolute or relative intensities of the wavelength bands can 15 As discussed herein , optical imager systems can also be provide information about chemical concentrations. For configured as active optical imager systems. Active optical example , chlorophyll content of certain crops can be esti- imager systems can differ from passive optical imager mated using only a few wavelength bands . Similar tech- systems in that active optical imager systems emit their own niques can be used to find valuable minerals or identify light into a field and detect the emitted light after it has toxins . Spectral information can also be used to assist in the 20 reflected off surface( s ) of an object in the field . In some classification of pedestrians, automobiles, and other objects embodiments, active optical imager systems can be utilized similarly encountered in an automotive environment. as LIDAR devices where emitted and received , reflected A graduated neutral -density filter has a transmission that light can be correlated to determine a distance to the object varies spatially across the filter, but the transmission is from which the emitted light was reflected . A better under largely independent of wavelength (e.g. just as transmissive 25 standing of an active optical imager system can be ascer to red light as to blue light) at any given location . In a tained with reference to FIG . 4 .

scanning imaging system , a graduated neutral -density filter FIG . 4 illustrates a block diagram of a LIDAR system 400 can be used to image the same point in space with varying according to some embodiments of the present disclosure . degrees of attenuation , thereby enabling a composite mea- LIDAR system 400 can include a light ranging device 402 surement with higher dynamic range than would achievable 30 and a user interface 415. Light ranging device 402 can with a non - graduated filter. A better understanding of a include a ranging system controller 404 , a light transmission micro - optic receiver layer with graduated filter can be (Tx ) module 406 and a light sensing (Rx) module 408 . achieved with reference to FIGS . 3A and 3B . Ranging data can be generated by light ranging device 402 FIGS . 3A and 3B are perspective views of a simplified by transmitting one or more light pulses 410 from the light diagram of different embodiments of micro - optic receiver 35 transmission module 406 to objects in a field of view layers with graduated filter layers, according to some surrounding light ranging device 402. Reflected portions embodiments of the present disclosure. Specifically, FIG . 412 of the transmitted light are then detected by light sensing 3A is a perspective view of a simplified diagram of a module 408 after some delay time . Based on the delay time , micro -optic receiver layer 300 with a graduated filter layer the distance to the reflecting surface can be determined . 302 , and FIG . 3B is a perspective view of a simplified 40 Other ranging methods can be employed as well , e.g. diagram of a micro - optic receiver layer 301 with a graduated continuous wave , Doppler, and the like. filter layer 312. As illustrated in FIGS . 3A and 3B , micro- Tx module 406 includes an emitter array 414 , which can optic receiver layer 300 and 301 each includes four micro- be a one - dimensional or two - dimensional array of emitters , optic receiver channels 304 , 306 , 308 and 310 arranged in and a Tx optical system 416 , which when taken together

two dimensions as a 2x2 array. Although FIGS . 3A and 3B 45 with emitter array 414 can form a light emission system 438 . illustrate embodiments having only 2x2 arrays , one skilled Tx optical system 416 can include a bulk transmitter optic in the art understands that such embodiments are not limit- that is image - space telecentric. In some embodiments, Tx ing and that other embodiments can be configured to have optical system 416 can further include one or more micro any number of micro - optic receiver channels. It is to be optic structures that increase the brightness of beams ema appreciated that in these diagrams, the thicknesses of filter 50 nating from the bulk transmitter optic as discussed herein layers 302 and 312 and the thicknesses of the surrounding with respect to FIGS . 11-14 and / or for beam shaping , beam layers, which are not drawn to scale , should be interpreted steering or the like. Emitter array 414 or the individual as the thicknesses of layers of refractive material in an emitters can be laser sources . Tx module 406 can further interference filter. As these thicknesses change, the charac- include an optional processor 418 and memory 420 , teristics (e.g. passband CWL ) of the interference filter 55 although in some embodiments these computing resources change. These embodiments can be used in a hyperspectral can be incorporated into ranging system controller 404. In passive optic imager system . some embodiments, a pulse coding technique can be used , As shown in FIGS . 3A and 3B , graduated filter layer 302 e.g. , Barker codes and the like . In such cases , memory 420

has gradually increasing thickness in one dimension across can store pulse - codes that indicate when light should be multiple columns of micro -optic receiver channels, and 60 transmitted. In some embodiments, the pulse - codes are graduated filter layer 312 has a step - wise - increasing thick- stored as a sequence of integers stored in memory . ness in one dimension that has a constant thickness for each Light sensing module 408 can be substantially similar in micro - optic receiver channel. Micro -optic receiver channels construction to light sensing module 106 discussed herein 304 and 308 have the same filter thickness and detect the with respect to FIG . 1. Thus, details of processor 422 , same wavelength of light. Micro - optic receiver channels 306 65 memory 424 , sensor array 426 , and Rx optical system 428 and 310 have the same filter thickness and detect the same ( when taken together with sensor array 426 can form a light wavelength of light. Micro -optic receiver channels 304 and detection system 436 ) can be referenced herein with respect

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to FIG . 1 , and only differences with respect to those com- with respect to FIGS . 5A and 5B , while exemplary scanning ponents are discussed herein for brevity. For LIDAR system LIDAR devices are discussed further herein with respect to 400 , each photosensor sensor ( e.g. , a collection of SPADs) FIGS . 6A , 6B , and 7 .

of sensor array 426 can correspond to a particular emitter of LIDAR system 400 can interact with one or more instan emitter array 414 , e.g. , as a result of a geometrical configu- 5 tiations of a user interface 415. The different instantiations ration of light sensing module 408 and Tx module 406. For can vary and can include, but not be limited to , a computer example , in some embodiments, emitter array 414 can be system with a monitor, keyboard, mouse , CPU and memory ; arranged along the focal plane of the bulk transmitter optic a touch - screen in an automobile or other vehicle ; a handheld such that each illuminating beam projected from the bulk device with a touch - screen ; or any other appropriate user transmitter optic into the field ahead of the system is 10 interface . User interface 415 can be local to the object upon substantially the same size and geometry as the field of view which LIDAR system 400 is mounted but can also be a of a corresponding receiver channel at any distance from the remotely operated system . For example , commands and data system beyond an initial threshold distance . to / from LIDAR system 400 can be routed through a cellular In some embodiments, processor 418 can perform signal network (LTE , etc. ), a personal area network (Bluetooth , processing of the raw histograms from the individual photon 15 Zigbee , etc. ) , a local area network (WiFi, IR , etc.), or a wide detectors ( or groups of detectors ) in the array. As an example area network such as the Internet. of signal processing, for each photon detector or grouping of User interface 415 of hardware and software can present photon detectors, memory 424 ( e.g. , SRAM ) can accumulate the LIDAR data from the device to the user or to a vehicle counts of detected photons over successive time bins , and control unit (not shown) but can also allow a user to control these time bins taken together can be used to recreate a time 20 LIDAR system 400 with one or more commands. Example series of the reflected light pulse ( i.e. , a count of photons vs. commands can include commands that activate or deactivate time ) . This time- series of aggregated photon counts is the LIDAR system , specify photodetector exposure level , referred to herein as an intensity histogram (or just histo- bias , sampling duration and other operational parameters gram ). Processor 418 can implement matched filters and ( e.g., emitted pulse patterns and signal processing), specify peak detection processing to identify return signals in time . 25 light emitters parameters such as brightness. In addition , In addition , Processor 418 can accomplish certain signal commands can allow the user to select the method for processing techniques ( e.g. , by processor 422 ) , such as displaying results. The user interface can display LIDAR multi - profile matched filtering to help recover a photon time system results which can include , e.g. , a single frame series that is less susceptible to pulse shape distortion that snapshot image , a constantly updated video image , and / or a can occur due to SPAD saturation and quenching. In some 30 display of other light measurements for some or all pixels . embodiments, all or parts of such filtering can be performed In some embodiments, user interface 415 can track distances by processor 458 , which may be embodied in an FPGA. (proximity ) of objects from the vehicle , and potentially In some embod nts , the photon time series output from provide alerts to a driver or provide such tracking informa processor 418 are sent to ranging system controller 404 for tion for analytics of aa driver's performance. further processing, e.g. , the data can be encoded by one or 35 In some embodiments, for example where LIDAR system more encoders of ranging system controller 404 and then 400 is used for vehicle navigation , user interface 415 can be sent as data packets to user interface 415. Ranging system a part of a vehicle control unit that receives output from , and controller 404 can be realized in multiple ways including , otherwise communicates with light ranging device 402 e.g. , by using a programmable logic device such an FPGA , and / or user interface 415 through a network , such as one of as an ASIC or part of an ASIC , using a processor 430 with 40 the wired or wireless networks described above. One or memory 432 , and some combination of the above . Ranging more parameters associated with control of a vehicle can be

system controller 404 can cooperate with a stationary base modified by the vehicle control unit based on the received controller or operate independently of the base controller LIDAR data. For example, in a fully autonomous vehicle , ( via pre -programmed instructions ) to control light sensing LIDAR system 400 can provide a real time 3D image of the module 408 by sending commands that include start and 45 environment surrounding the car to aid in navigation in stop light detection and adjust photodetector parameters . conjunction with GPS and other data . In other cases , LIDAR Similarly, ranging system controller 404 can control light system 400 can be employed as part of an advanced driver transmission module 406 by sending commands, or relaying assistance system ( ADAS ) or as part of a safety system that, commands from the base controller, that include start and e.g. , can provide 3D image data to any number of different stop light emission controls and controls that can adjust 50 systems , e.g. , adaptive cruise control, automatic parking, other light -emitter parameters ( e.g. , pulse codes ) . In some driver drowsiness monitoring, blind spot monitoring , colli embodiments, ranging system controller 404 has one or sion avoidance systems , etc. When user interface 415 is more wired interfaces or connectors for exchanging data implemented as part of aa vehicle control unit, alerts can be with light sensing module 408 and with light transmission provided to a driver or tracking of a proximity of an object module 406. In other embodiments, ranging system control- 55 can be tracked .

ler 404 communicates with light sensing module 408 and A. Solid State Architecture light transmission module 406 over a wireless interconnect LIDAR systems , according to some embodiments of the such as an optical communication link . present disclosure, can be configured as a solid state LIDAR Light ranging device 402 can be used in both stationary system that has a stationary architecture. Such LIDAR and a scanning architectures . Electric motor 434 is an 60 systems do not rotate , and thus do not need a separate motor, optional component in LIDAR system 400 that can be used e.g. , electric motor 434 in FIG . 4 , to rotate the sensor and to rotate system components, e.g. , the Tx module 406 and transmitter modules. Example solid state LIDAR systems Rx module 408 , as part of a scanning LIDAR architecture. are shown in FIGS . 5A and 5B .

The system controller 404 can control the electric motor 434 FIGS . 5A and 5B are simple illustrations of exemplary and can start rotation , stop rotation and vary the rotation 65 implementations of solid state LIDAR systems. Specifically, speed as needed to implement a scanning LIDAR system . FIG . 5A illustrates an implementation 500 where solid state Exemplary stationary LIDAR devices are discussed below LIDAR systems 502a - d are implemented at the outer

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regions of a road vehicle 505 , such as an automobile, rotating column or platform or through the use of other according to some embodiments of the present disclosure; mechanical means , such as galvanometers. Chip -based and FIG . 5B illustrates an implementation 501 where solid beam steering techniques can also be employed, e.g. , by state LIDAR systems 504a - b are implemented on top of using microchips that employ one or more MEMS based road vehicle 505 , according to some embodiments of the 5 reflectors, e.g. , such as a digital micromirror (DMD ) device , present disclosure . In each implementation, the number of a digital light processing (DLP ) device , and the like . In some LIDAR systems , the placement of the LIDAR systems , and embodiments, the scanning can be effectuated through non the fields of view of each LIDAR system can be chosen to mechanical means , e.g. , by using electronic signals to steer obtain a majority of, if not the entirety of, a 360 degree field one or more optical phased arrays. of view of the environment surrounding the vehicle . Auto- 10 Other embodiments can implement a scanning architec motive implementations for the LIDAR systems are chosen ture that scans through the entire 360 degrees of the envi herein merely for the sake of illustration and the sensors ronment surrounding a vehicle . Such scanning LIDAR sys described herein may be employed in other types of tems can repetitively rotate continuously through 360 vehicles, e.g. , boats, aircraft, trains, etc., as well as in a degrees in a clockwise or counter - clockwise direction, and variety of other applications where 3D depth images are 15 thus may utilize a separate motor, e.g. , electric motor 434 in useful, such as medical imaging, mobile phones, augmented FIG . 4 , to rotate the sensor and transmitter modules . Exem reality, geodesy, geomatics, archaeology, geography, geol- plary rotating LIDAR systems are shown in FIGS . 6A and ogy , geomorphology, seismology, forestry, atmospheric 6B .

physics, laser guidance, airborne laser swath mapping FIG . 6A is a top - down view of a simplified diagram of an (ALSM) , and laser altimetry. 20 exemplary scanning LIDAR system 600 implemented for a With reference to FIG . 5A , solid state LIDAR systems vehicle 605 , such as a car, and capable of continuous 360 502a - d can be mounted at the outer regions of a vehicle , near degree scanning, according to some embodiments of the the front and back fenders. LIDAR systems 502a - d can each present disclosure . The output beam ( s ) of one or more light be positioned at a respective corner of vehicle 505 so that sources ( such as infrared or near - infrared pulsed IR lasers , they are positioned near the outermost corners of vehicle 25 not shown ) located in LIDAR system 600 , can be scanned , 505. That way, LIDAR systems 502a - d can better measure e.g. , rotated , to illuminate a continuous scene 620 around the the distance of vehicle 505 from objects in the field at areas vehicle . In some embodiments , the scanning, represented by 506a - d . Each solid state LIDAR system can face a different rotation arrow 615 , can be implemented by any suitable direction ( possibly with partially and / or non -overlapping mechanical means discussed herein with respect to FIG . 5B , fields of views between units ) so as to capture a composite 30 e.g. , by mounting the light emitters to a rotating column or field of view that is larger than each unit is capable of platform , or any other mechanical means , such as through capturing on its own . Objects within the scene can reflect the use of galvanometers or chip -based steering techniques . portions of light pulses 510 that are emitted from LIDAR TX During operation, objects around vehicle 605 in any direc module 508. One or more reflected portions 512 of light tion and within the view of LIDAR system 600 can reflect pulses 510 then travel back to LIDAR system 502a and can 35 portions of light pulses 611 that are emitted from a trans be received by Rx module 509. Rx module 509 can be mitting module 608 in LIDAR system 600. One or more disposed in the same housing as Tx module 508 . reflected portions 617 of light pulses 611 then travel back to Although FIG . 5A illustrates four solid state LIDAR LIDAR system 600 and can be detected by its sensing systems mounted at the four corners of a vehicle , embodi- module 609. In some instances, sensing module 609 can be ments are not limited to such configurations. Other embodi- 40 disposed in the same housing as transmitting module 608 . ments can have fewer or more solid state LIDAR systems Although FIG . 6A illustrates solid state LIDAR systems mounted on other regions of a vehicle . For instance , LIDAR mounted on a roof of aa vehicle 605 , embodiments are not systems can be mounted on a roof of a vehicle 505 , as shown limited to such configurations. Other embodiments can have in FIG . 5B . In such embodiments, LIDAR systems can have solid state LIDAR systems mounted on other regions of a a higher vantage point to better observe areas 506a - d around 45 vehicle. For instance , LIDAR systems can be mounted at the vehicle 505 . corners of a vehicle , as shown in FIG . 6B . FIG . 6B illustrates B. Scanning Architecture an implementation 601 where solid state LIDAR systems In some embodiments, LIDAR systems according to the 604a - d are implemented at the outer regions of a road present disclosure can employ a scanning architecture in vehicle , such as a car, according to some embodiments of the which the LIDAR system oscillates between an angle that is 50 present disclosure . In this implementation, each LIDAR less than 360 degrees. For instance , LIDAR systems 504a - b system 604a - d can be a spinning LIDAR system that can in implementation 501 of FIG . 5B can each employ a measure distances around the full 360 degrees. However, scanning architecture to scan the entire scene in front of, since at least some of those measurements will be measured and / or behind, vehicle 505 , e.g. , in area 514 between field of with respect to vehicle 605 , those measurements can be view 506? and 506b and in area 516 between field of view 55 ignored . Thus, each LIDAR system 605a - d can only utilize 506c and 506d . The output beam ( s ) of one or more light a subset of the measurements from 360 degree scanning, sources ( not shown , but can be a variety of different suitable e.g. , only the angles covering regions 619a - d that do not sources for emitting radiation including, but not limited to capture vehicle 605 are utilized .

lasers, in any wavelength spectrum suitable for LIDAR FIG . 7 is a simplified exemplary perspective view of a systems , such as in the infrared , near - infrared , ultraviolet, 60 LIDAR system 700 that employs a 360 scanning architec visible , e.g. , green laser wavelength spectrum , and the like ) ture, according to some embodiments of the present disclo located in the scanning LIDAR systems , can be outputted as sure. In some embodiments, LIDAR system 700 can include pulses of light and scanned , e.g. , rotated between an angle a light ranging device 701 that spins in a clockwise or that is less than 360 degrees, to illuminate a scene around the counter -clockwise direction to observe the surrounding field vehicle. In some embodiments, the scanning, represented by 65 around a vehicle. System 700 can include a stationary rotation arrows 514 and 516 , can be implemented by housing 702 , an optically transparent window 704 , and a

mechanical means , e.g. , by mounting the light emitters to a stationary lid 706 for providing protection for the internal

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components of LIDAR system 700. Window 704 can extend circular field of view 832 (the size of which is exaggerated fully around a periphery of stationary housing 702 , which for the sake of clarity ). Likewise , emitter 816 emits an can be configured to have a cylindrical shape . The internal illuminating beam 818 (also called an emitter channel) into components of system 700 can include light ranging device the circular field of view 834. While not shown in FIG . 8 to 701 , which can include a rotating platform 708 and sensing 5 avoid complication, each emitter emits a corresponding and transmitting modules 710 mounted on rotating platform illuminating beam into its corresponding field of view 708. In some embodiments, light ranging device 701 is resulting in a 2D array of fields of view being illuminated aligned with window 704 such that modules 710 are posi- (21 distinct fields of view in this example ). tioned to emit and receive light through window 704 , and Each field of view that is illuminated by an emitter can be that emitted light is not emitted onto stationary housing 702 10 thought of as a pixel or spot in the corresponding 3D image or stationary lid 706. For instance , in the aligned positioned , that is produced from the ranging data . Each emitter channel the horizontal center of light ranging device 701 coincides can be distinct to each emitter and be non -overlapping with with the horizontal center of window 704. Sensing and other emitter channels, i.e. , there is a one - to - one mapping transmitting modules 710 can be , for example, light sensing between the set of emitters and the set of non - overlapping module 408 and light transmission module 406 , and can 15 fields or view . Thus, in the example of FIG . 8 , the system can optionally include a heat sink ( not shown ) to cool the sample 21 distinct points in the 3D space. A denser sampling micro - optic layers . LIDAR system 700 can also include a of points can be achieved by having a denser array of system controller 712 ( e.g. , controller 404 ) and electric emitters or by scanning angular position of the emitter motor 714 ( e.g. , motor 434 ) that reside within stationary beams over time such that one emitter can sample several housing 702. Electric motor 714 rotates platform 708 , 20 points in space . As described above, scanning can be accom thereby rotating sensing and transmitting modules 710 in a plished by rotating the entire emitter/ sensor assembly . spinning manner, e.g. , continuously through 360 degrees in Each sensor can be slightly offset from its neighbor and , a clockwise or counter - clockwise direction . System control- like the emitters described above, each sensor can see a ler 712 can communicate with sensing and transmitting different field of view of the scene in front of the sensor. modules 710 using an optical communication link 716. 25 Furthermore , each sensor's field of view substantially coin Optical communication link 716 allows sensing and trans- cides with, e.g. , overlaps with and is the same size as a mitting modules 710 to communicate with stationary system respective emitter channel's field of view. controller 712 , which is mechanically coupled to stationary In FIG . 8 , the distance between corresponding emitter housing 702 and does not rotate with platform 708 , through receiver channels is exaggerated relative to the distance to optical communication link 716 without mechanical wear 30 objects in the field of view. In practice, the distance to the and tear. In some embodiments, system controller 712 can objects in the field of few is much greater than the distance control the motor and to start and stop light detection between corresponding emitter -receiver channels and thus operations of LIDAR system 700. System controller 712 can the path of light from the emitter the object is approxi include two or more stacked planar circuit boards arranged mately parallel to the path of the reflected light back from in a parallel relationship , which is discussed in more detail 35 the object to the sensor ( i.e. , it is almost “ back reflected ” ). in commonly - owned and concurrently - filed U.S. Patent Accordingly, there is a range of distances in front of the Application No. 16/ 209,867 , filed Dec. 4 , 2018 , now U.S. system 800 over which the fields of view of individual Patent No. 10,481,269 , issued Nov. 19,2019 , which is herein sensors and emitters are overlapped .

incorporated by reference in its entirety for all purposes . Because the fields of view of the emitters are overlapped which is herein incorporated by reference in its entirety for 40 with the fields of view of their respective sensors, each all purposes. receiver channel ideally can detect the reflected illumination III . Operation of Active Imager Systems beam that originates from its respective emitter channel with FIG . 8 is an illustrative example of the light transmission ideally no cross - talk , i.e. , no reflected light from other and detection operation for a light ranging system according illuminating beams is detected. Thus, each photosensor can to some embodiments . FIG . 8 shows a light ranging system 45 correspond to a respective light source . For example, emitter 800 (e.g. , solid state or and /or scanning system) collecting 812 emits an illuminating beam 814 into the circular field of three - dimensional distance data of a volume or scene that view 832 and some of the illuminating beam reflects from surrounds the system . FIG . 8 is an idealized drawing to the object 830. Ideally, a reflected beam 824 is detected by highlight relationships between emitters and sensors , and sensor 822 only. Thus, emitter 812 and sensor 822 share the thus other components are not shown. 50 same field of view, e.g. , field of view 832 , and form an Light ranging system 800 includes a light emitter array emitter - sensor pair. Likewise , emitter 816 and sensor 826 810 and a light sensor array 820. The light emitter array 810 form an emitter - sensor pair, sharing field of view 834. While includes an array of light emitters, e.g. , an array of vertical- the emitter - sensor pairs are shown in FIG . 8 as being in the cavity surface -emitting lasers (VCSELs ) and the like , such same relative locations in their respective array, any emitter as emitter 812 and emitter 816. Light sensor array 820 55 can be paired with any sensor depending on the design of the includes an array of photosensors, e.g. , sensors 822 and 826 . optics used in the system .

The photosensors can be pixelated light sensors that employ, During a ranging measurement, the reflected light from for each photosensor, a set of discrete photodetectors such as the different fields of view distributed around the volume single photon avalanche diodes (SPADs) and the like . How- surrounding the LIDAR system is collected by the various ever , various embodiments can deploy other types of photon 60 sensors and processed , resulting in range information for sensors . any objects in each respective field of view. As described Each emitter can be slightly offset from its neighbor and above, a time -of - flight technique can be used in which the can be configured to transmit light pulses into a different light emitters emit precisely timed pulses , and the reflections field of view from its neighboring emitters, thereby illumi- of the pulses are detected by the respective sensors after nating a respective field of view associated with only that 65 some elapsed time . The elapsed time between emission and emitter. For example, emitter 812 emits an illuminating detection and the known speed of light is then used to beam 814 ( formed from one or more light pulses ) into the compute the distance to the reflecting surface . In some

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embodiments, additional information can be obtained by the for the measurement. The N pulse trains can reflect from an sensor to determine other properties of the reflecting surface object, thereby allowing a ranging measurement to the in addition to the range . For example, the Doppler shift of a object. Each of the N pulse trains can include one or more pulse can be measured by the sensor and used to compute the pulses from the light source (e.g. , VCSELs ) and correspond relative velocity between the sensor and the reflecting sur- 5 to a different time interval that is triggered by a start signal. face. The pulse strength can be used to estimate the target In some embodiments , the CPOS can wait for a specified reflectivity, and the pulse shape can be used to determine if time to allow a previous pulse train ( coded -pulse transmis the target is a hard or diffuse material. sion ) to dissipate . The CPOS can then transmit a next pulse In some embodiments, the LIDAR system can be com- train of the N pulse trains of a measurement, where the N posed of a relatively large 2D array of emitter and receiver 10 pulse trains form a code . Once a measurement is complete , channels and operate as a solid state LIDAR , i.e. , it can e.g. , a last of the N pulse train has dissipated ( e.g. , after a obtain frames of range data without the need to scan the predetermined time expected for any reflections), the CPOS orientation of the emitters and /or sensors . In other embodi- can then start the first/next coded- pulse transmission using ments, the emitters and sensors can be scanned, e.g. , rotated the appropriate pulse -code. N can be an integer greater than about an axis , to ensure that the fields of view of the sets of 15 one , e.g. , 2 , 3 , 4 , 5 , or higher. emitters and sensors sample a full 360 degree region (or At 930 , optical detection can be started , e.g. , in response some useful fraction of the 360 degree region) of the to the start signal that triggers the pulse train to be trans surrounding volume. The range data collected from the mitted . Thus, the CPOS can start light detection at the same scanning system , e.g. , over some predefined time period, can time that it started coded- pulse transmission . As part of the then be post - processed into one or more frames of data that 20 optical detection , a pulse train can be detected by a photo can then be further processed into one or more depth images sensor (e.g. , corresponding to a pixel ) of the optical mea or 3D point clouds . The depth images and / or 3D point clouds surement system , thereby generating data values at a plu can be further processed into map tiles for use in 3D rality of time points. In some embodiments, the photosensor mapping and navigation applications. is a collection of photodetectors (e.g. , SPADs). The data According to some embodiments, a light ranging system 25 values may be of various forms, e.g. , counts of a number of

( also called a coded -pulse optical receiver system) can SPADs that triggered at a time point ( e.g. , within a time bin transmit multiple pulses of light. In some embodiments, of a histogram ). As other examples, the data values can be each coded -pulse has an embedded positive -valued pulse- a digitized value from an ADC that follows an analog code formed by the light intensity. The system can determine photosensor ( e.g. , an APD ) . Both examples can correspond the temporal position and / or amplitude of optical pulses in 30 to an intensity. In total , N pulse trains can be detected . the presence of background light by creating an intensity Further, the process can be performed separately for each histogram of detected, reflected light at different time bins . photosensor of the optical measurement device . For each time bin, the system adds a weighted value to the At 940 , a weight is assigned to the data values time intensity histogram that depends on the intensity of detected points within the time interval corresponding to the pulse light. The weighted values can be positive or negative and 35 train , thereby obtaining weighted values . A weight can be have varying magnitudes. assigned for each of the N pulse trains. Some of such By selecting different combinations of positive -valued weights for different pulse trains can be the same as other pulse - codes and applying different weights, the system can pulse trains . In some embodiments, at least two of the N detect positive -valued and negative - valued codes suitable pulse trains are assigned different weights and have a for standard digital signal processing algorithms. This 40 different pulse pattern . Two pulse trains can have some approach gives a high signal -to -noise ratio while maintain- similarity ( e.g. , portions of pulses can overlap ), but there is ing a low uncertainty in the measured temporal position of at least some times where one pulse train is ON and the other the reflected light pulses . pulse train is OFF . Such different pulse patterns can have a FIG . 9 is a flowchart illustrating a method 900 of using similar shape but have aa different delay, e.g. , { 1 , 0 , 1, 1, 0 } coded pulses in an optical measurement system according to 45 has a similar shape of non -zero values to { 0 , 1 , 0 , 1 , 1 ) , but embodiments of the present disclosure. The optical mea- they are different pulse patterns due to an offset as may be surement system may be a light ranging system . Method 900 achieved by a delay in the second signal relative to the first can detect the temporal position of a reflected pulse from a signal.

target using multiple coded -pulses . In a real -time three- Accordingly, the CPOS can detect light and create a dimensional application, method 900 can constantly detect 50 digitized intensity value for each light - sampling - interval. distances to objects in the surrounding environment. Method For each light - sampling - interval, the CPOS can apply a 900 may be implemented by any of the optical measurement pulse -weight to the digitized intensity value and add the systems described herein . result to the appropriate time -bin of the intensity histogram . At 910 , a coded -pulse optical system (CPOS ) performs an At 950 , the CPOS tests if it has sent the required number initialization . For example , the CPOS can respond to user 55 of coded -pulses . If the CPOS has sent the required number interface commands for starting, stopping, and changing of coded -pulses it continues at block 960 , otherwise it loops parameters. The CPOS can initialize an optical transmitter to back to block 920 .

indicate parameters, e.g. , pulse - codes , light power level , and At 960 , a histogram corresponding to the weighted values various time intervals (e.g. , for a detection interval, an in a plurality of time bins is determined . As described above , interval for pausing between detection intervals, and an 60 a counter of the histogram at a particular time bin can be overall measurement time interval). The CPOS can initialize determined by accumulating the weighted values at time a light sensing module to indicate parameters such as points within the particular time bin across a plurality of pulse -time- interval and light -sampling - interval. The CPOS time intervals .

can also clear histogram values . At 970 , the histogram is used to detect a signal corre At 920 , a pulse train is transmitted from a light source 65 sponding to the N pulse trains. For example , the CPOS can ( e.g. , a laser) as part of an optical measurement. The pulse determine whether the histogram has a sequence of values train can be transmitted as part of N pulse trains transmitted that match the match - code ( filter ). The CPOS can report

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whether the match - code was found and the amplitude of the system can transmit at least three unique codes , which could match . The match may allow detection of the desired signal be weighted with three different polar angles and sum to a relative to noise or interference from other light sources . single 2 - D vector. An N - D vector (defined with N separate As an example , a filter can include a set of values to be numbers all held within a single “ bin ” ) would require N + 1 applied to a window of time bins of a histogram . The filter 5 different codes , each weighted at a different angle ( in other can be slid over the histogram to calculate a filtered histo- worlds having a component to its weight that is orthogonal gram having counters corresponding to different sliding to all other weights ) when doing the vector summation . By positions of the profile filter relative to the histogram . Each increasing the dimensionality, more advanced coding tech of the counters of the filtered histogram can correspond to an niques like quadrature phase coding or code division mul overlap of the profile filter and the histogram at a particular 10 tiple access (CDMA ) that are used in RF communications sliding position . A maximum value of the counters of the may be used . An N - dimensional matched filter can be used filtered histogram can be identified , thereby allowing detec- in this context.

tion, e.g. , when the maximum value is above a threshold. As a LIDAR system implements method 900 during its The particular sliding position for the maximum value of the operation, the LIDAR system can continuously measure counters can correspond to the received time , which may be 15 distances to objects in the field . Accordingly, once the used for ranging measurements . distance to an object is determined , method 900 can loop In some embodiments , the signal may be a reflected signal back to block 920 to begin another series of emitting pulse caused by the N pulse trains reflecting from an object, e.g. , trains and detecting the emitted pulse trains to determine a when the optical measurement system is configured to histogram for determining a distance to an object in the field . perform ranging measurements . In other embodiments, the 20 Distances may need to be constantly measured by method signal may be a communication signal , e.g. , when the light 900 because the LIDAR system may need to be constantly source is at one location and the photosensors are at a measuring distances to objects in the field, such as when the different location . Such a configuration can be used for LIDAR system is used for navigational purposes and the communication purposes. For example, a microwave trans- LIDAR system is moving within the field .

mission tower can transmit data to a receiving tower. The 25 In some embodiments, after determining the distance to transmitted data can include coded pulses , which may help the object at block 980 , method 900 can determine whether to reduce errors in data reception as may be caused by noise an exit command has been received by CPOS at block 990 . or interference from other sources . The receiving tower can If an exit command has been received , then method 900 can identify pulse trains and create a histogram by selecting an stop measuring distances at block 999 , otherwise method arbitrary time between two pulse trains as a start time for a 30 900 can continue measuring distances to objects by looping first time bin . A match filter can then be applied (e.g. , by back to block 920 .

sliding over the histogram ); and if a sufficient match is As mentioned above , method 900 can be used to reduce found, then that communication signal can be detected . A interference among channels. For example, method 900 can sufficient match can be measured by the maximum value be repeated for a plurality of channels of light sources and obtained the filtered histogram . As a further embodiment, 35 photosensors as part of a plurality of optical measurements . the system can detect an interference signal from another The plurality of optical measurements can overlap in time , CPOS in a similar manner used to detect the communication e.g. , performed substantially simultaneously. Thus, each signal. If interference is measured , some implementations channel can perform a measurement at the same time . To can change the transmitted code , e.g. , of the interference reduce interference , the codes can be different for at least code is similar to the code currently being used . 40 some of the channels. For example, the pulse patterns of the At 980 , a distance to the object can be determined . For N pulse trains of at least two channels of the plurality of example, a received time corresponding to the N pulse trains channels can be different, thereby causing different histo relative to the start signal can be determined . A distance to gram patterns for different channels . In addition or instead , the object can be determined using the received time . The the weights assigned to the N pulse trains of at least two received time may be offset from the transmission times of 45 channels of the plurality of channels can be different, the pulse trains, but such an offset can be taken into account. thereby causing different histogram patterns for different Accordingly, the CPOS can report the time at which it was channels.

detected . The distance can corresponds to a round trip time IV . Construction of Active Imager Systems between the received time and aa start time of the start signal, FIG . 10 is a simplified diagram illustrating a detailed view and thus the distance may be expressed in time . 50 of an exemplary active optical imager system 1000 having The detected signal can be used for other purposes than a wide field -of - view and capable of narrowband imaging , ranging. For example, the quality of the detected signal can according to some embodiments of the present disclosure . be used to measure the reflectivity of an object. For example , Active optical imager system 1000 can employ solid state or if the detected signal has a strong intensity, then the system scanning architectures as aforementioned herein . In some can determine that the object has aa high reflectivity. Imple- 55 embodiments, active optical imager system 1000 can mentations for communications and interference measure- include a light detection system 1001 and a light emission ments are discussed above . For detection of interference system 1002 , which is unlike passive optical imager sys from another light source , the detected signal would be from tems . Light emission system 1002 provides active illumi another set of pulse trains transmitted by the interfering light nation of at least a portion of a field in which system 1000 source . 60 is positioned with narrowband light rays 1004. Light detec As a generalization, embodiments can transmit N + 1 tion system 1001 detects the narrowband light emitted from unique codes with N + 1 unique weights to generate an N the light emission system 1002 after it has been reflected by dimensional vector space histogram . For example, instead of objects in the field as reflected light rays 1006. Light a bin holding a signed number, the bin can hold a 1 - D vector detection system 1001 can be substantially similar to light ( e.g. , equivalent to a signed number ), by transmitting at least 65 detection system 200 discussed herein with respect to FIG . two unique codes : one positive and one negative . To store a 2. Thus, details of bulk receiver optic 1008 , light cone 1010 , 2 - D vector (e.g. , in polar or Cartesian coordinates), the micro - optic receiver channel 1012 in micro -optic receiver

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layer 1014 , and photodetectors 1016 can be referenced have a small enough footprint to be adopted for use in herein with respect to FIG . 2 , and are not discussed herein mass -market automobiles , trucks and other vehicles . For for brevity. example , some embodiments include a set of vertical - cavity In some embodiments , light emission system 1002 surface - emitting lasers ( VCSELs) as illumination sources includes aa bulk transmitter optic 1018 and a light emitting 5 that emit radiation into a field and include arrays of single layer 1020 formed of a one- or two - dimensional array of photon avalanche diode (SPAD ) detectors as a set of pho light emitters 1022. Each light emitter 1022 can be config- tosensors ( detectors ) that detect radiation reflected back ured to generate discrete beams of narrowband light. In from a surface in the field . Using VCSELs as the emitters some embodiments, light emitting layer 1020 is configured and SPADs as the detectors enables multiple measurements to selectively project the discrete beams of light through 10 to be taken at the same time ( i.e. , the VCSEL emitters can bulk transmitter optic 1018 according to an illumination be fired simultaneously ) and also enables the set of emitters pattern that matches, in size and geometry across a range of and the set of photosensors to each be fabricated using distances from light emission system 1002 , the fields of view standard CMOS processes on a single chip , greatly simpli of the receiver channels in micro - optic receiver channel fying the manufacturing and assembly process . array 1014. Light emitters 1022 can be any suitable light 15 Using VCSELs and SPADs in certain embodiments pres emitting device, such as a vertical- cavity surface - emitting ents challenges , however, that various embodiments of the lasers (VCSELS ) integrated on one or more monolithic chip , present disclosure overcome . For example, VCSELs are or any other type of laser diode . Light emitters 1022 can much less powerful than typical lasers used in existing produce cones of narrowband light 1024 that are directed to LIDAR architectures and SPADs are much less efficient than bulk transmitter optic 1018 , which can collimate cones of 20 the typical detectors used in the existing LIDAR architec light 1024 and then output the collimated light to distant tures. To address these challenges, as well as challenges targets in the field as emitted light rays 1004. In some presented by firing multiple emitters simultaneously, certain embodiments, bulk transmitter optic 1018 is image - space embodiments of the disclosure include various optical com telecentric . ponents ( e.g. , lenses , filters, and an aperture layer ), which In additional and alternative embodiments, light rays 25 may work in concert with multiple arrays of SPADs, each 1004 from light cones 1024 are focused on an intermediate array corresponding to a different pixel ( e.g. , position in the plane in space by a micro -optic transmitter layer ( not shown) field ), as described herein . For example , as discussed herein before being directed to distant targets by the bulk trans- with respect to FIG . 2 , a light detection system 200 can mitter optic 1018 to enhance the brightness and intensity of include a micro - optic receiver layer 204 for enhancing the light emitted from light emission system 1002. In such 30 light detected by photosens nsors 216 , e.g. , SPADs. embodiments, embodiments, light emission system 1002 Because VCSELs are less powerful than typical lasers in and light detection system 1001 are configured such that existing LIDAR architectures, in some embodiments, light each micro - optic transmitter channel (not shown) is paired emission system 1002 can be configured to improve the with a corresponding micro - optic receiver channel 1012 and ability of imager system 1000 to perform light ranging the centers of their fields -of - view are aligned to be overlap- 35 functionality. That is , the quality of light emitted by light ping at a certain distance from the sensor or their chief rays emission system 1002 can be enhanced to improve light are made parallel. In further additional and alternative ranging accuracy and efficiency. The quality of transmitted embodiments, the far - field beams of light emitted by light light for light ranging and imaging purposes can be defined emission system 1002 are of similar size and divergence in terms of brightness and intensity . The brightness and angle to the far - field fields -of - view of each micro - optic 40 intensity of light rays 1004 emitted from bulk transmitter receiver channel 1012. Details of light emission systems optic 1018 can be enhanced by modifying and / or imple 1002 having the micro - optic transmitter layer for enhancing menting one or more optic transmitter layers , as will be brightness and intensity of outputted light will be discussed discussed further herein .

in detail below. Brightness of a transmitting light can be defined by the As is evident from the illustration of parallel light rays 45 optical power ( in watts ) per solid angle . Thus, light sources 1004 and 1006 in FIG . 10 , each micro -optic receiver channel that output light with tight collimation, i.e. , low divergence, 1012 has a non - overlapping field of view beyond aa threshold produce light that are high in brightness. Conversely, light distance. As shown in FIG . 10 , each micro - optic receiver sources that output light with high divergence produce light channel 1012 includes an aperture from the plurality of that are low in brightness. Intensity of light can be defined apertures, a lens from the plurality of lenses, and a photo- 50 by the optical power per area, meaning light emitted with a detector from the plurality of photodetectors , where the certain power will have higher intensity if it tightly com aperture of each channel defines a discrete field of view for pacted in a small area . Accordingly, light sources that output the pixel in the channel that is non- overlapping beyond a light in a tightly compacted ray will have higher intensity threshold distance within the fields of view of the other than light sources that output light in a less compacted ray , micro - optic receiver channels . That way, each micro -optic 55 even if both light sources output light that has low diver receiver channel receives reflected light corresponding to a gence . As will be appreciated herein , transmitter compo discrete position in the field that is not measured by any nents for LIDAR systems in embodiments of the present other micro - optic receiver channel in micro - optic receiver disclosure can be configured with micro -optical components channel layer 1014 . that enable the transmitter to output light that has enhanced A. Enhancing Brightness and Intensity of Transmitters in 60 brightness and intensity as compared to a similar transmitter Active Imager Systems without the micro-optical components. Embodiments of the present disclosure pertain to a FIG . 11 is a simplified cross - sectional view diagram of a LIDAR sensor that can , among other uses , be used for first exemplary enhanced light emission system 1100 , obstacle detection and avoidance in autonomous vehicles. according to some embodiments of the present disclosure. Some specific embodiments pertain to LIDAR sensors that 65 Light emission system 1100 can include a light emitter array include design features that enable the sensors to be manu- 1102 having light emitters 1104 that for example may factured cheaply enough and with sufficient reliability and to comprise without limitation any of LEDs , laser diodes ,

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VCSELs , or the like for emitting light 1113. A VCSEL is a away from both the light emitter and micro optic channel, type of semiconductor laser diode with laser beam emission the light forms a light cone 1112 reaching out towards bulk perpendicular from the top surface . Note that the linear array transmitter optic 1114 .

shown in FIG . 11 can be any geometric form of emitter According to some embodiments of the present disclo array, including and without limitation circular, rectangular, 5 sure, the degree of divergence of emitted light 1113 can be linear, or any other geometric shape. smaller than the degree of divergence of light cone 1112 . Enhanced light emission system 1100 can include a This discrepancy in divergence can be created by a micro micro - optic transmitter channel array 1106 separated from power optic transmitter channel 1108 , specifically by the optical light emitter array 1102 by an open space 1118. Each of second optical surface 1121. Because the diver micro - optic transmitter channel 1108 is paired with a cor 10 gence of light out of micro - optic transmitter channel 1108 is larger than the divergence of emitted light 1113 from light responding receiver channel (e.g. , receiver channel 1012 in emitters 1104 , miniature spot image 1110 can be a real image FIG . 10 ) and the centers of their fields -of - view are aligned of light emitter 1104 but a multitude smaller than the size of to be overlapping at a certain distance from the optical light emitter 1104 and with the same number of photons as imager system . Micro - optic transmitter channel array 1106 15 emitted light 1113. The resulting light cone 1112 formed can be formed of a substrate 1119 sandwiched between aa first after the real spot images are formed then gets projected into optical surface 1120 positioned on a side facing light emitter the field as discrete beams of light for each light emitter 1104 array 1102 and a second optical surface 1121 positioned on after passing through bulk transmitter optic 1114. The result an opposite side facing away from light emitter array 1102 . ing light rays emanating out of light emission system 1100 Both first and second optical surfaces 1120 and 1121 can 20 are highly collimated beams of light that have a small each be configured as an array of convex , micro - optic lenses cross - sectional area ( smaller than the surface area of light where each convex lens of first optical surface 1120 is emitter 1104 ) , thereby resulting in a light emission system configured to be optically aligned with a respective convex 1100 that can output light having enhanced brightness and lenses of second optical surface 1120 so that light transmit intensity.

ting through first optical surface 1120 can subsequently be 25 Note that bulk transmitter optic 1114 can include either a transmitted through second optical surface 1121. The cor single lens or a cluster of lenses where two or more lenses responding convex lenses from first and second optical function together to form bulk transmitter optic 1114. The surfaces 1120 and 1121 can face away from one another as use of multiple lenses within the bulk transmitter optic 1114 shown in FIG . 11. In certain embodiments, convex lenses of could increase the numerical aperture, reduce the RMS spot first optical surface 1120 have a first optical power and 30 otherwise size, flatten the image plane, improve the telocentricity, or convex lenses of second optical surface 1121 have a second 1114. Noteimprove the performance of bulk transmitter optic optical power different from the first optical power. For may overlapalsoforming that for some embodiments, light cones 1112 cone overlap region 1116 .

instance, the second optical power can be greater than the To better understand the operation and effectiveness of first optical power such that the focal length of the second 35 micro - optic transmitter channel array 1106 , a more detailed optical power is shorter than the focal length of the first explanation of the operation of light emission system 1100 optical power. Substrate 1119 can be formed of any suitable is discussed . For enhanced light emission systems 1100 material that is transmissive in the wavelength range of the utilizing a light emitter array formed of VCSEL emitters, an light emitters 1104 such silicon , silicon dioxide , borosilicate exemplary initial radius for an emitter might be 12.5 um glass , polymer, and the like . First and second optical sur- 40 with light admitted in a 10 ° half angle cone . Such emitters faces 1120 and 1121 can be formed of a transparent polymer would typically output 50 W per square micron of active that is imprinted on respective opposite surfaces of substrate area . A diverging light cone from each emitter 1104 is 1119 . accepted into a micro - optic transmitter channel 1108 , and In some embodiments, micro - optic transmitter channel then a converging light cone is output by that same micro array 1106 can be formed of aa monolithic array of micro- 45 optic channel to produce a converging light cone with aa half optic transmitter channels 1108. Each micro - optic transmit- angle of for example 20 ° . Thus for some embodiments , the ter channel 1108 can include a first convex lens from first cone angle produced by an emitter 1104 is smaller than the optical surface 1120 , a corresponding second convex lens cone angle produced by a corresponding micro - optic trans from second optical surface 1121 , and a corresponding mitter channel 1108. The converging light cone emanated by portion of substrate 1119 positioned between the two convex 50 micro - optic transmitter channel 1108 then produces a min lenses . Each micro - optic transmitter channel 1108 can cor- iature spot image 1110 of the emitter. For the embodiment respond with a respective light emitter 1104 so that light according to FIG . 11 , miniature spot image 1110 is a real outputted from the light emitter 1104 first passes through the image and has a size that is smaller than the size of a first convex lens , through the corresponding region of sub- corresponding light emitter 1104. Note that all rays from a strate 1119 , and then through the second convex lens during 55 given emitter may not all be focused into an arbitrarily small operation . spot . The miniature spot image size is typically controlled by Once light emits out of the second convex lens of second an “ optical invariant " :

optical surface 1121 , the light forms a miniature spot image 1110 that is aa real image of the corresponding light emitter e * r_e 1104 but a reduced - size of the corresponding light emitter 60 where _s is the marginal ray half angle of the focused spot , 1104. In some embodiments, miniature spot images 1110 are r_s is the radius of the focused spot , O_e is the marginal ray positioned between micro - optic transmitter channel array half angle of the original emitter, and r_e is the radius of the 1106 and bulk transmitter optic 1114. For instance , miniature original emitter. So , in this example , the smallest miniature spot images 1110 can be formed within respective apertures spot image radius that could be formed (while still capturing of an aperture layer 1109. Each aperture can be a pin hole in 65 all the rays from the emitter) is : a reflective or opaque layer in which emitted light focuses to form miniature spot images 1110. From there, continuing 10 /20 * 12.5 um =6.25 um

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Note that this smaller spot will have one fourth the area to be optically aligned with a respective light emitter 1204 of the original emitter, and thus has a power density of 200 so that light outputted by the respective light emitter 1204 W per square micron of spot area . Each micro -optic can transmit through the respective convex lens of optical transmitter channel 1108 typically has one or more optical surface 1220. Convex lenses from optical surface 1220 can surfaces , having characteristics that may for example and 5 face away from their respective light emitters 1204 as shown without limitation include aa focal length of 50 um , and a lens in FIG . 12 so that their focal points are positioned further diameter of 80 um . For some embodiments, the distance from light emitter 1204. In certain embodiments, convex between light emitter 1104 and a corresponding micro -optic lenses of optical surface 1220 have an optical power suitable transmitter channel 1108 may be for example and without for converging the emitted light into real miniature spot limitation 150 um . Open space 1118 between emitter array 10 images 1210 that are real images of corresponding light 1102 and micro - optic transmitter channel array 1106 as emitters 1204 but reduced - size images of the corresponding shown in FIG . 11 may be , for example and without limita- light emitters 1204 like the convex lenses of second optical tion an air gap such as that produced by methods typically surface 1121 in FIG . 11. Optical surface 1120 enables the used to manufacture MEMS devices. The distance between emitted light to diverge into light cones 1212 before pro emitter array 1102 and micro - optic transmitter channel array 15 jecting through bulk imaging optic 1214. Substrate 1219 and 1106 for example may be 150 um . optical surface 1220 can be formed of similar materials as Bulk transmitter optic 1114 is positioned in front of the substrate 1119 and optical surfaces 1120 and 1121 discussed micro - optic and emitting layers such that the focal plane of herein with respect to FIG . 11. In some embodiments , light the bulk imaging optic coincides with miniaturized spot cones 1212 may overlap forming cone overlap region 1216 . images 1110. Bulk transmitter optic 1114 accepts divergent 20 Embodiments herein can also implement micro -optic light cone ( s ) 1112 and outputs a collimated beam . Its channel arrays that do not include convex lenses and that do numeric aperture can be at least large enough to capture the not generate real images of the light emitters. Rather, some full range of angles in the divergent ray cone ( s ) , so for embodiments may implement concave surfaces to generate example and without limitation the Numerical Aperture virtual images of the light emitters, as discussed further (NA ) = 0.34 in this example . Also , bulk transmitter optic 1114 25 herein with respect to FIG . 13 . can be image - space telecentric , since light cone ( s ) 1112 FIG . 13 is a simplified cross - sectional view diagram of a exiting the micro -optic layer may all be parallel ( rather than third exemplary enhanced light emission system 1300 , having their center axes aimed towards the center of the bulk according to some embodiments of the present disclosure . optic ) . In one embodiment, light can exit bulk transmitter Similar to first and second exemplary enhanced light emis optic 1114 approximately collimated . Note that the quality 30 sion systems 1100 and 1200 , third exemplary enhanced light of beam collimation relates to the size of the “ emitting emission system 1300 can include bulk imaging optic 1314 object ” (miniature spot images 1110 ) at the focal plane. and light emitter array 1302. However, unlike first and Since this “ emitting object” size has been reduced by using second exemplary light emission systems 1100 and 1200 , a micro - optic stack , a better collimation angle is obtained third exemplary light emission system 1300 can include a than if the emitter object was simply imaged directly. 35 micro - optic transmitter channel array 1306 that includes an Although FIG . 11 shows an enhanced light emission array of concave surfaces instead of an array of convex system having a micro -optic channel array formed of a lenses , as shown in FIG . 13 .

substrate sandwiched between first and second optical sur- In such embodiments, micro - optic transmitter channel faces, and positioned a distance away from a light emitter array 1306 can be formed of a substrate 1319 and an optical array by an open space to improve the brightness and 40 surface 1320. Optical surface 1320 can be a first surface intensity of light outputted by the light emission system , 1330 of substrate 1319 positioned toward bulk imaging optic embodiments are not limited to such configurations. Rather, 1314 and away from light emitters 1304. Second surface other embodiments may not necessarily implement an open 1331 of substrate 1319 can be located opposite of first space or two optical surfaces, as discussed further herein surface 1330 and positioned against light emitter array 1302 with respect to FIG . 12 . 45 so that light emitted from emitters 1304 can first pass FIG . 12 is a simplified cross - sectional view diagram of a through substrate 1319 before passing through optical sur second exemplary enhanced light emission system 1200 , face 1320. Optical surface 1320 can each be configured as according to some embodiments of the present disclosure. an array of concave surfaces where each concave surface of Similar to first exemplary enhanced light emission system optical surface 1320 is configured to be optically aligned 1100 , second exemplary enhanced light emission system 50 with a respective light emitter 1304 so that light outputted by 1200 can include bulk imaging optic 1214 and light emitter the respective light emitter 1304 can transmit through the array 1202. However, unlike first exemplary light emission respective concave surface of optical surface 1320. In cer system 1100 , second exemplary light emission system 1200 tain embodiments , the concave surfaces of optical surface can include a micro - optic transmitter channel array 1206 1320 have an optical power suitable for forming virtual that is positioned directly upon an emission surface of light 55 miniature spot images 1310 that are virtual images of emitter array 1202 instead of being separated by an open corresponding light emitters 1304 but reduced -size images space/ air gap , as shown in FIG . 12 . of the corresponding light emitters 1304 , and further enable In such embodiments , micro -optic transmitter channel the emitted light to diverge into light cones 1312 before array 1206 can be formed of a substrate 1219 and an optical projecting through bulk imaging optic 1314. In some surface 1220. Optical surface 1220 can be positioned on a 60 embodiments, virtual miniature spot images 1310 are first surface 1230 of substrate 1219. Second surface 1231 of formed within substrate 1319 as shown in FIG . 13. In some substrate 1219 can be located opposite of first surface 1230 embodiments, light cones 1312 may overlap forming cone and positioned against light emitter array 1202 so that light overlap region 1316. Substrate 1319 can be formed of emitted from emitters 1204 can first pass through substrate similar materials as substrate 1119 discussed herein with 1219 before passing through optical surface 1220. Optical 65 respect to FIG . 11 .

surface 1220 can be configured as an array of convex lenses Note that the lens configurations for the micro -optic where each convex lens of optical surface 1220 is configured channels for embodiments described in each of FIGS . 11 , 12

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and 13 differs with respect to how many surfaces have within the same protective structure, e.g. , stationary housing optical power and the shapes of those surfaces. The first 702 , optically transparent window 704 , and stationary lid embodiment shown in FIG . 11 benefits from the ability to 706 in FIG . 7. Light emitted from the light emission system , use two optical power surfaces on opposite sides of a in some embodiments, exits out of transparent window 704 ,

substrate , which could allow each surface to be shallower, 5 and light detected by light detection system may first enter spherical rather than aspherical, or otherwise more easily into transparent window 704. The curvature of transparent manufactured . This embodiment includes a spacer structure window 704 can induce some optical aberrations, such as ( not shown) to maintain an offset between the micro -optic astigmatism . Because the transparent window can have a channel array 1106 and the light emitter array 1102. An cylindrical structure and be well - controlled , it can be cor example of such a spacer structure would be aa silicon wafer 10 rected with one or more additional optical structures. In with channels formed via deep reactive ion etching. The some embodiments, light emission and / or detection systems second embodiment shown in FIG . 12 benefits from having can be configured with corrective optical structures to com only one optical power surface on a substrate that is attached pensate for the astigmatism caused by the transparent win to the light emitter array. This type of configuration simpli- dow, as discussed further herein . fies fabrication while also achieving enhanced brightness 15 FIGS . 15A - 15C are cross - sectional views of simplified and intensity. The third embodiment shown in FIG . 13 diagrams of exemplary active imager systems having dif shares the benefits of the embodiment shown in FIG . 12 but ferent implementations of corrective optical structures for has a single optical surface that is formed of concave astigmatism , according to some embodiments of the present surfaces rather than convex lenses ; concave features can disclosure . Specifically, FIG . 15A is a simplified cross often be easier to fabricate at the micro - scale . 20 sectional view diagram of an active imager system 1500 In some embodiments, bulk imaging optics for light having a corrective optical structure as part of the bulk emission systems can include one or more aperture stops to imaging optic , FIG . 15B is a simplified cross - sectional view reduce stray light emitted by the system . For instance , FIG . diagram of an active imager system 1501 having a corrective 14 is a simplified cross - sectional view diagram of an exem- optical structure as part of the micro -optic receiver channel plary enhanced light emission system 1400 configured with 25 array, and FIG . 15C is a simplified cross - sectional view bulk optics that have aperture stops , according to some diagram of an active imager system 1502 having a corrective embodiments of the present disclosure. FIG . 14 is substan- optical structure as part of the micro -optic transmitter chan tially similar to FIG . 1 with the addition of aperture stop nel array. Active imager systems 1500 , 1501 , and 1502 each variants 1403 , 1405 , and 1406 for bulk transmitter optic include a light detection system 1504 and a light emission 1414. Aperture stop ( s ) shown in FIG . 14 can be used with 30 system 1506. Components of active imager systems 1500 , any of FIGS . 11 through 13. In FIG . 14 , aperture stops 1403 , 1501 , and 1502 are substantially similar to active optical 1405 , and 1407 , can have circular or oval openings for light imager system 1000 in FIG . 10 with the addition of the to pass through , although any opening shape may be utilized corrective optical structures . us , the components that are without deviating from the spirit and scope of the present shared with active optical imager system 1000 are not disclosure . 35 discussed for brevity.

In some embodiments , aperture stop 1403 can be located As shown in FIG . 15A , active imager system 1500 can be on a side of bulk transmitter optic 1414 facing away from housed within an enclosure containing a transparent window light emitter array 1402 and micro -optic transmitter channel 1508. Transparent window 1508 is at least transparent to the array 1406. In some additional and alternative embodiments, wavelength of light at which emitters 1510 operate . The aperture stop 1405 can be located on a side of bulk trans- 40 curved shape of transparent window 1508 can induce an mitter optic 1414 facing toward light emitter array 1402 and optical aberration , such as an astigmatism , in light rays 1511 micro - optic transmitter channel array 1406. In yet some emitted from light emission system 1506 when light rays additional and alternative embodiments where bulk receiver 1511 exit the enclosure through transparent window 1508 . optic 114 includes a plurality of lenses working together, Light rays 1512 then enter back into the enclosure through aperture stop 1407 can be formed of one or more aperture 45 transparent window 1508 after reflecting off of an object in stops placed within the plurality of lenses that form bulk the field , which can induce an additional optical aberration transmitter optic 1414 . to the received light rays. To correct for these optical The various configurations and locations of aperture stops aberrations, light detection system 1504 can include correc 1403 , 1405 , and 1407 can dictate the way each aperture stop tive bulk imaging optic 1514 specifically designed to com functions in the light emitting system . For example, if all the 50 pensate for the expected astigmatism induced by transparent light cones 1412 are compressed to be substantially over- window 1508. For example , corrective bulk imaging optic lapping near the location of aperture stop 1407 , then the size 1514 can include a corrective lens 1516 in addition to bulk of the aperture stop 1407 would be able control both the receiver optic 1518. Corrective lens 1516 can be any suitable initial diameter of the emitted collimated beams as well as lens capable of negating the astigmatism caused by trans reject the marginal rays emitted by light emitters 1404. 55 parent window 1508 , such as a cylindrical lens . Corrective Rejecting certain ray angles could effectively narrow the lens 1516 can be positioned between transparent window spectrum of light emitted out of the bulk optic , since the 1508 and bulk receiver optic 1518 in some embodiments, or wavelength of light emitted by many types of lasers varies between bulk receiver optic 1518 and micro - optical receiver with angle. Alternatively, perhaps this best location for the channel array 1505 in some other embodiments . Similarly, a aperture stop would occur at 1402 or 1403 , depending upon 60 corrective bulk optic could be included in the bulk trans the design of the bulk transmitter optic 1414. Multiple mitter optic of the light emission system 1506 . aperture stops may be used simultaneously - e.g. 1402 , Instead of incorporating the corrective optics into the bulk 1403 , and 1404 all in one bulk transmitter optic 1414 — to imaging optics , the corrective optics can be implemented reduce stray light emitted by light emitting system 1400 . into a micro -optical receiver channel array in some embodi B. Optical Corrections for Astigmatism 65 ments. For instance , with reference to FIG . 15B , light As mentioned herein with respect to FIG . 7 , light detec- detection system 1504 can include a corrective lens array tion systems and light emission systems can be enclosed 1520 in front of apertures 1522 , e.g. , on the opposite side of

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apertures 1522 from where photosensors 1526 are posi- field . Ideally, no stray light should be received by any tioned . That way, light cones 1524 can propagate through channel, as shown in FIG . 16A .

respective corrective lenses to compensate for astigmatism FIG . 16A is a simplified cross - sectional view diagram of caused by transparent window 1508 before projecting on part of a light detection system 1600 where there is no photosensors 1526. In some embodiments, corrective lens 5 cross - talk between channels. During operation , perpendicu array 1520 is formed of an array of cylindrical lenses that lar light rays 1602 and chief ray 1604 enter the bulk imaging can negate the astigmatism caused by transparent window optic 1604 1606 and produce light cone 1608. Light rays 1602 and enter an aperture of aperture layer 1610 and enter 1508. Each corrective lens of corrective lens array 1520 can be positioned in alignment with a respective aperture 1522 10 limited rangelensof incident collimating 1611. Collimating lens 1611 accepts a light angles . For example, colli so that corrective lens array 1520 can negate the astigmatism mating lens 1611 can accept light rays at incident angles caused by transparent window 1508 for light received by between +25 to -25 degrees relative to the perpendicular. each photosensor 1526 . FIG . 16A shows light cone 1608 with incident angles Although FIGS . 15A and 15B illustrate ways in which a between +25 to -25 degrees. The chief ray 1604 is the light light detection system portion of a LIDAR system can be 15 ray that passes through the center of the modified to correct for astigmatism caused by transparent example, the chief ray 1604 has an incident angle of 0 aperture . In this window 1508 , embodiments are not limited to such con degrees on the collimating lens 1611 . figurations and corrective optics can be implemented in light FIG . 16B is a simplified cross - sectional view diagram of emission systems as well . For example , with reference to part of a light detection system 1601 where there is cross FIG . 15C , active imager system 1502 can include a correc- 20 talk between channels. In this case , during operation, tive lens array 1528 in front of aperture layer 1530 , e.g. , on oblique light rays 1612 and chief ray 1614 enter bulk the opposite side of aperture layer 1530 from where light receiver optic 1616 and later enter collimating lens 1621. In emitters 1510 are positioned . That way, light emitted from this example, collimating lens 1621 belongs to a micro -optic light emitters 1510 can propagate through respective cor- channel that corresponds to a photosensor further from the rective lenses 1528 before emitting to bulk transmitter optics 25 center of the image . In this example, chief ray 1614 has an 1534. In this case , respective corrective lenses 1528 can incident angle of -12 degrees and the cone of focused light induce a corrective degree of astigmatism in the emitted has incident angles between +12 degrees to -35 degrees. light in anticipation of, and to compensate for, the astigma- Collimating lens 1621 rejects some of the light rays because tism caused by transparent window 1508 as light is emitted it only accepts light with incident angles between +25 to -25 out of light emission system 1506. In some embodiments, 30 degrees. Additionally, the rays that are outside of the colli corrective lens array 1528 is formed of an array of biconical mating lens acceptance cone can travel to other optical lenses that can induce an equal but opposite degree of surfaces and become stray light. Thus, a non - telecentric bulk astigmatism caused by transparent window 1508 . tus , the imaging optic will deliver significantly fewer signal photons amount of astigmatism induced by corrective lens layer to the photodetector, while potentially polluting other chan 1528 can be offset by the degree of astigmatism caused by 35 nels with errant light rays 1622. A telecentric bulk imaging transparent window 1508 , thereby effectively achieving optic , on the other hand, will produce light cones with little to no net astigmatism during operation of active imager incident angles approximately between +25 to -25 degrees system 1502. Each corrective lens of corrective lens array and chief rays with incident angles on the collimating lens 1528 can be positioned in alignment with a respective of approximately 0 degrees, regardless of the angle of the aperture 1532 so that corrective lens array 1528 can induce 40 oblique rays 1612 and chief ray 1614. A telecentric bulk a corrective degree of astigmatism to negate the astigmatism imaging optic has similar benefits for the transmitter when caused by transparent window 1508 for light received by the lasers are telecentric (their chief rays are all parallel) as each photosensor 1526. In some embodiments, corrective is the case for VCSELS or a side emitter diode laser bar. lens array 1528 may not be needed . Instead , optical surface In some embodiments , the light detection system of a light 1536 can be an array of biconical lenses instead of an array 45 sensing module uses an input image - space telecentric bulk of cylindrical lenses . The biconical structure of the lenses imaging optic . In some other embodiments, for example can induce an amount of astigmatism to offset the degree of where cost or increased field of view is more important than astigmatism caused by transparent window 1508. In these performance , the light detection system may use a more embodiments, corrective lens array 1528 may not be imple- standard input bulk imaging optic such as a bi - convex lens.

mented in light emission system 1506. Furthermore, in some 50 For any given input field into an image - space telecentric embodiments, instead of ( or in conjunction with) a correc- lens , the resulting chief rays are parallel to the optical axis, tive micro - optic lens array, a corrective bulk cylindrical lens and the image - side ray cones all span approximately the can be implemented with bulk receiver optic 1534 ( similar same set of angles . This allows micro - optic channels far to the embodiment shown in FIG . 15A for light detection from the optical axis in the light detection system to achieve system 1504).Thus, light emission system 1506 can include 55 similar performance to the on-axis micro -optic channel. The a corrective bulk imaging optic in front of its bulk receiver light detection system does not need perfect image space optic 1534 to negate the astigmatism caused by transparent telecentricity for this to work , but the closer to perfect window 1508 . telecentricity the better. For a micro - optic receiver optical V. Mitigating Receiver Channel Cross - Talk layer lens that can only accept +/- 25 degree light, the As can be appreciated by disclosures herein, channels in 60 preference is that the input bulk imaging optic produce the micro - optic receiver and are positioned very close to one image - side rays that are no greater than 25 degrees in angle another, often times within microns of one another. This for every point on the focal plane .

small spacing between each channel can invite the oppor- In certain embodiments , specific light detection systems tunity for problems to arise . For instance, light propagating having wide field of view and narrowband imaging can have through bulk imaging optic can occasionally cause stray 65 an input image - space telecentric bulk imaging optic with a light to bleed into neighboring channels, thereby resulting in numerical aperture (NA ) equal to 0.34 and focal length of 20 inaccurate readings of reflected light for each pixel in the mm . Similarly, some other embodiments could have a 1 nm

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wide bandpass filter, thereby enabling it to detect light of a detect photons incident on photosensor 1771. Photo very specific wavelength. The light detection system is sensor 1771 herein refers to a single photodetector capable of supporting FOVs greater than 30 degrees. capable of detecting photons, e.g. , an avalanche pho According to some embodiments of the present disclo- todiode, a SPAD ( Single Photon Avalanche Detector ), sure , the design of each channel of the micro -optic receiver 5 RCP (Resonant Cavity Photo -diodes ), and the like , or channel array can be specifically configured to have features several photodetectors , such as an array of SPADS, that minimize the intrusion of stray light onto a respective cooperating together to act as a single photosensor, photodetector, thereby reducing or eliminating any detri often with higher dynamic range, lower dark count rate, mental effects caused by the occurrence of stray light. FIG . or other beneficial properties as compared to a single 17 is a simplified cross - sectional diagram of an exemplary 10 large photon detection area . Each photodetector can be micro - optic receiver channel structure 1700 , also called a an active area that is capable of sensing photons , i.e. , micro - optic receiver channel in discussions herein . Receiver light. Photosensor layer 1770 refers to a layer made of channel 1700 can be representative of micro - optic receiver photodetector (s ) and contains optional structures to channels 232 and 1032 , among others, shown in FIGS . 2 and improve detection efficiency and reduce cross talk with 10 , respectively, and serves to accept an input cone of light 15 containing a wide range of wavelengths, filters out all but a neighboring receiver structures. Photosensor layer narrow band of those wavelengths centered at the operating 1770 may optionally include diffusers, converging wavelength , and allows photosensor 1771 to detect only or lenses , apertures, optically non - transparent tube spacer substantially only photons within the aforementioned nar- structures, optically non - transparent conical spacer row band of wavelengths. According to some embodiments 20 structures, etc.

of the present disclosure, micro - optic receiver channel struc- Stray light may be caused by roughness of optical sur tures, such as receiver channel 1700 , can include the fol- faces, imperfections in transparent media, back reflections, lowing layers : and the like, and may be gen rated at many features within An input aperture layer 1740 including an optically trans- the receiver channel 1700 or external to receiver channel parent aperture 1744 and optically non -transparent stop 25 1700. The stray light may be directed: through the filter region 1746 configured to define a narrow field of view region 1761 along a path non -parallel to the optical axis of when placed at the focal plane of an imaging optic such collimating lens 1751 ; reflecting between aperture 1744 and as bulk receiver optic 202 or 1008 ( shown in FIGS . 2 collimating lens 1751 ; and generally taking any other path or and 10 , respectively; not shown in FIG . 17) . Aperture trajectory possibly containing many reflections and refrac layer 1740 is configured to receive the input marginal 30 tions . If multiple receiver channels are arrayed adjacent to ray lines 1733. The term “ optically transparent” herein one another, this stray refers to as allowing most or all light to pass through . absorbed by a photosensorlight in one receiver channel may be Light herein refers to spectrum of light in the near contaminating the timing , phasein, oranother channel, thereby other information inher ultraviolet, visible , and near - infrared range (e.g. 300 nm to 5000 nm). Optically non -transparent herein 35 feature ent to photons . Accordingly, receiver channel 1700 may several structures to reduce crosstalk between refers to as allowing little to no light to pass through , but rather absorbing or reflecting the light. Aperture receiver channels .

layer 1740 can include optically transparent apertures As will be understood further herein , each layer of a separated from each other by optically non - transparent micro - optic channel layer structure can be designed spe stop regions. The apertures and stop regions can be 40 cific way to mitigate the detrimental effects of stray light. built upon a single monolithic piece such as an opti- Various different designs for each layer will now be dis cally transparent substrate . Aperture layer 1740 can cussed in further detail below .

optionally include a one -dimensional or two- dimen- A. Aperture Layer sional array of apertures 1744 . In an embodiment having aperture layer 1740 , as shown

An optical lens layer 1750 including a collimating lens 45 in FIG . 17 , optically transparent aperture 1744 and optically 1751 characterized by a focal length, offset from the non - transparent stop region 1746 can be formed from a plane of aperture 1744 and stop region 1746 by the single monolithic piece , such as a metal foil with a pinhole focal length , aligned axially with aperture 1744 , and or from a single layer of a deposited opaque or reflective configured to collimate photons passed by the aperture material having apertures etched therethrough . such that they are traveling approximately parallel to 50 FIG . 18A is a simplified cross - sectional view diagram of the axis of collimating lens 1751 which is aligned with a different embodiment 1800 where aperture layer 1840 has the optical axis of receiver channel 1700. Optical lens two apertures 1844. Both the optically transparent apertures layer 1750 may optionally include apertures, optically 1844 and corresponding optically non -transparent optical non - transparent regions and tube structures to reduce stop regions 1846 are supported on an optically transparent cross talk. 55 substrate 1845. Bottom aperture 1844 can be smaller and be An optical filter layer 1760 including an optical filter positioned at the focal plane of the bulk optic . Aperture layer 1761 , typically a Bragg reflector type filter, adjacent to 1840 can be followed by optically transparent spacer struc collimating lens 1751 and opposite of aperture 1744 . ture 1856 positioned between aperture 1844 and collimating Optical filter layer 1760 can be configured to pass lens 1851 in the receiver channel. Optically transparent normally incident photons at a specific operating wave- 60 spacer structure 1856 forms a tube of substantially similar or length and passband. Optical filter layer 1760 may larger diameter to collimating lens 1851 .

contain any number of optical filters 1761. Optical filter FIG . 18B is aa simplified cross - sectional view diagram of layer 1760 may optionally include apertures, optically a different embodiment 1801 of aperture layer 1840. Opti non - transparent regions and tube structures to reduce cally transparent aperture 1844 and optically non -transpar cross talk. 65 ent stop region 1846 are supported on optically transparent A photosensor layer 1770 including a photosensor 1771 substrate 1845. Optically transparent spacer structure 1856 adjacent to optical filter layer 1760 and configured to that follows aperture layer 1840 and positioned between

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aperture 1844 and collimating lens 1851 forms a tube of FIG . 19C is a simplified cross - sectional view diagram of substantially similar or larger diameter to collimating lens an embodiment 1902 of aperture layer 1940 where aperture 1851 . 1944 is conically aligned , and where the conical structure as FIG . 18C is a simplified cross - sectional view diagram of an optically non -transparent layer coated on an optically an embodiment 1802 of aperture layer 1840 consisting of 5 transparent material.

multiple optically non - transparent stop regions 1846 that are FIG . 19D is a simplified cross - sectional view diagram of supported on optically transparent substrate 1845. These an embodiment 1903 of aperture layer 1940 where the layers ( stop regions 1846 ) follow the contour of marginal aperture 1944 is conically aligned, and where the conical light rays ( not shown, but similar to light rays 1733 in FIG . structure is a solid structure formed of an optically non 17 ) to reduce stray light into the receiver channel. Optically 10 transparent material. As shown in FIGS . 19C and 19D the transparent spacer structure 1856 below aperture layer 1840 optically transparent aperture 1944 and optically non -trans forms a tube of substantially similar or larger diameter to parent stop region 1946 are combined into a monolithic collimating lens 1851 . layer with aa conical cavity aligned with the optical axis of FIG . 18D is a simplified cross - sectional view diagram of the receiver channel and configured to conform to the shape an embodiment 1803 of aperture layer 1840 having multiple 15 of marginal ray lines ( not shown, but similar to light rays optically non - transparent stop layers 1846 supported on 1733 in FIG. 17) .

multiple optically transparent substrate 1845. Aperture layer C. Optical Filter Layer 1840 follows the contour of marginal light rays ( not shown , FIG . 20A is a simplified cross - sectional view diagram of but similar to light rays 1733 in FIG . 17 ) to reduce stray light an embodiment 2000 of filter layer 2060 for a receiver into the receiver channel. Optically transparent spacer struc- 20 channel, according to some embodiments of the present ture 1856 below aperture layer 1840 forms a tube of sub- disclosure . Optical filter layer 2060 can include a single stantially similar or larger diameter to collimating lens 1851 . optical filter 2061 supported on an optically transparent In some other embodiments of the present disclosure , substrate 2065. Optical filter layer 2060 can be placed on top spacer structure 1856 shown in FIGS . 18A - D , can be of optically transparent substrate 2065 or below optically optically non - transparent. The optically non -transparent 25 transparent substrate 2065. Optical filter 2061 can be a spacer structure in this instance could be formed by etching bandpass filter that blocks incident light outside of a defined a silicon or glass wafer and may be coated with an optically set of wavelengths ( e.g. 945-950 nm ). However, in some non -transparent material ( e.g. black chrome). Additionally, other embodiments, optical filter 2061 can be an edge pass the spacer structure in this instance would prevent any light filter or any other suitable type of filter that selectively in the spacer region from traveling outside the receiver 30 allows light within a wavelength range to pass through itself. channel. FIG . 20B is a simplified cross - sectional view diagram of B. Spacer Structure Between Aperture Layer and Optical an embodiment 2001 of filter layer 2060 for a receiver Lens Layer cha el , according to some embodiments of the present FIG . 19A is a simplified cross - sectional view diagram of disclosure. Optical filter layer 2060 can include two optical an embodiment 1900 of the present disclosure with an 35 filters 2061 sandwiching and supported by an optically optically non - transparent spacer structure between the aper- transparent substrate 2065. Optical filter layer 2060 can ture layer and the lens layer. FIG . 19A depicts an optically contain any number of optical filters 2061 on any number of non - transparent spacer structure 1956 positioned between substrates 2065. One of the optical filters 2061 as shown in aperture 1944 and collimating lens 1951 in the receiver FIG . 20B can be a bandpass filter and can be positioned on channel. Optically non - transparent spacer structure 1956 40 either on top of or directly below optically transparent forms a tube of substantially similar or larger diameter to substrate 2065 that blocks all of the incident light for a collimating lens 1951 and prevents any light from traveling defined set of wavelengths ( e.g. 900-945 nm and 950-995 outside the receiver channel in the region between aperture nm ). The other optical filter 2061 placed on the opposite side 1944 and collimating lens 1951. Optically non - transparent of the optical substrate 2065 can be a wide spectrum spacer structure 1956 could be formed by etching a silicon 45 blocking filter ( except for the region covered by the band or glass wafer and may be coated with an optically non- pass filter ), for example covering 200-915 nm and 980-1600 transparent material ( e.g. black chrome ). Alternatively, opti- nm . The bandpass filter and blocking filter are designed such cally non - transparent spacer structure 1956 could be a solid that there is no leakage in the transition region between the non - transparent structure that is fabricated from molded two filters . However, the filters could be two edge pass filters polymer or any other suitable method . FIG . 19A shows the 50 designed to work in conjunction as a bandpass filter or any aperture layer having optically transparent substrate 1945 on other types of filters .

the top , followed by the optically non - transparent stop In some other embodiments of the present disclosure , the region 1946 and aperture 1944 , and then by optically non- bandpass filter and wide spectrum blocking filter are merged transparent spacer structure 1956 . into a single optical filter 2061 and placed on either the top FIG . 19B is a simplified cross - sectional view diagram of 55 or bottom of optically clear substrate 2065 . an embodiment 1901 of the present disclosure with an 1. Filter Layer with Apertures optically non - transparent structure between the aperture FIG . 20C is a simplified cross - sectional view diagram of layer and the lens layer. FIG . 1901 depicts an optically an embodiment 2002 of filter layer 2060 for a receiver non - transparent spacer structure 1956 positioned between channel, according to some embodiments of the present aperture 1944 and collimating lens 1951. Optically non- 60 disclosure . Optical filter layer 2060 can have an additional transparent spacer structure 1956 forms a tube of substan- aperture 2049 on top and an additional aperture 2054 on the tially similar or larger diameter to collimating lens 1951 and bottom of optical filter layer 2060 along with the corre prevents any light from traveling outside of the receiver sponding optically non - transparent stop regions 2063 & channel in the region between aperture 1944 and collimating 2055. Aperture 2049 defines the maximal cylinder of light lens 1951. FIG . 19B shows multiple optically non -transpar- 65 desired to be passed into optical filter layer 2060 by optical ent stop regions 1946 supported on optically transparent filter 2061 , and stop region 2063 an absorb or reflect any substrate 1945 . incident stray light outside the diameter of aperture 2049 .

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Aperture 2054 defines the maximal cylinder of light desired FIG . 20G is a simplified cross - sectional view diagram of to be passed out of optical filter layer 2060 and stop region an embodiment 2006 of filter layer 2060 for a receiver 2055 absorbs or reflects any incident stray light outside the channel, according to some embodiments of the present diameter of aperture 2054. Optical filters 2061 can be disclosure . Optical filter layer 2060 can include two optical supported on an optically transparent substrate 2065 . 5 filters 2061 supported on optically transparent substrates In some embodiments of the present disclosure, filter 2065 and surrounded by an optically non- transparent tube structure 2111 , which prevents stray light in one optical filter layer 2060 can have a single aperture 2049 placed on the top layer of the optical filter layer 2060. In some additional and adjacent 2060 from traveling into an optical filter region of an alternative embodiments of the present disclosure, filter receiver channel in aa multi receiver channel system . layer 2060 can have a single aperture 2054 placed on the 10 However of optical, the optical filters 2061filter on region may contain any number any number of substrates 2065 bottom of optical filter layer 2060 . within the optical filter layer 2060. FIG . 20G illustrates an FIG . 20D is a simplified cross - sectional view diagram of additional aperture 2049 and corresponding optically non an embodiment 2003 of filter layer 2060 for a receiver transparent stop region 2063 positioned on top of optical channel , according to some embodiments of the present 15 filter 2061 and supported by optically transparent substrate disclosure . Optical filter layer 2060 can include multiple 2065. Aperture 2049 can define the maximal cylinder of optically transparent substrates 2065 , and multiple optically light desired to be passed into optical filter layer 2060 and non - transparent aperture layers between them in an alter stop region 2063 can absorb or reflect any incident stray nating order. FIG . 20D shows an additional aperture 2049 light outside the diameter of aperture 2049 . and corresponding optically non - transparent stop region 20 Embodiment 2006 of optical filter layer 2060 in FIG . 20G 2063 positioned on top of optical filter 2061 and supported can have an additional aperture 2054 , and corresponding by optically transparent substrates 2065. Aperture 2049 can optically non -transparent stop region 2055 can be positioned define the maximal cylinder of light desired to be passed into between optical filter layer 2060 and the photosensor layer optical filter layer 2060 by optical filter 2061 , and stop (not shown, but similar to photosensor layer 1770 in FIG . region 2063 absorbs or reflects any incident stray light 25 17) . Aperture 2054 can define the maximal cylinder of light outside diameter of aperture 2049. FIG . 20D shows an desired to be passed out of optical filter layer 2060 toward additional aperture 2054 and corresponding optically non- the photosensor, and stop region 2055 can absorb or reflect transparent stop region 2055 positioned between optical any incident stray light outside the diameter of aperture filter layer 2060 and a photosensor layer (not shown, but 2054. Tube structure 2111 can be formed of a variety of similar to photosensor layer 1770 in FIG . 17 ) . Aperture 2054 30 materials, including but not limited to silicon , metals, poly can define the maximal cylinder of light desired to be passed mers , or glasses .

out of optical filter layer 2060 toward the photosensor, and D. Photosensor Layer stop region 2055 can absorb or reflect any incident stray As can be appreciated herein , various different photosen light outside the diameter of aperture 2054. Collectively, sor layer designs can be implemented in a micro -optic these interleaved layers prevent stray light in one optical 35 receiver channel.

filter layer 2060 from traveling into an optical filter region 1. Photosensor Layer with Diffuser of an adjacent receiver channel in a multi receiver channel FIG . 21A is a simplified cross - sectional view diagram of system . an embodiment 2100 of receiver channel 2132 containing an 2. Filter Layer with Tube Structure optional diffuser 2181 located in photosensor layer 2170 FIG . 20E is a simplified cross - sectional view diagram of 40 between optical filter 2161 and photosensor 2173 , according an embodiment 2004 of filter layer 2060 for a receiver to some embodiments of the present disclosure. Diffuser channel, according to some embodiments of the present 2181 can be configured to spread collimated photons that are disclosure. Optical filter layer 2060 can include optical filter output from collimating lens 2151 and passed by optical 2061 and optically transparent substrate 2065 and be sur- filter region 2160 , across the full width of a corresponding rounded by an optically non - transparent tube structure 2111 , 45 photosensor 2173. Photosensor 2173 may be non - square or which prevents stray light in one optical filter layer 2060 non - circular in geometry (e.g. , short and wide) in order to from traveling into an optical filter region of an adjacent extend the sensing area of photosensor 2173 to be wider or receiver channel in a multi receiver channel system . Tube taller than width or height of the other components in structure 2111 can be formed of a variety of materials, receiver channel 2132 .

including but not limited to silicon, metals , polymers , or 50 Diffuser 2181 is configured to spread light rays across the glasses . area of photosensor 2173 such that photosensor 2173 able FIG . 20F is a simplified cross - sectional view diagram of to detect the incident photons across its full width and an embodiment 2005 of filter layer 2060 for a receiver height, thereby increasing the dynamic range of receiver channel, according to some embodiments of the present channel 2132 , even where the overall height of receiver disclosure . Optical filter layer 2060 can include optical filter 55 channel 2132 has to be limited for practical considerations . 2061 and optically transparent substrate 2065 and is sur- In particular, in this embodiment, receiver channel 2132 may rounded by an optically non - transparent tube structure 2111 , include widened photosensors exhibiting greater photode which prevents stray light in one optical filter layer 2060 tectors 2171 ( i.e. , areas sensitive to incident photons) and a from traveling into an optical filter region of an adjacent diffuser 2181 arranged over photosensor 2173 that spreads receiver channel in a multi receiver channel system . Tube 60 light passed by optical filter 2161 across the full area of structure 2111 can be formed of a variety of materials, photosensor 2173 , thereby yielding increased dynamic including but not limited to silicon, metals , polymers , or range .

glasses . As shown in FIG . 20F, tube structure 2111 may only In some embodiments, photosensor 2173 includes an pass partially through optical filter layer 2060. This type of array of single -photon avalanche diode detectors 2171 (here structure can be formed by performing deep anisotropic 65 inafter “ SPADs” ). The height and width of the receiver etches on each side of filter substrate 2065 and selectively channel ( usually defined by the diameter of collimating lens depositing metal or polymer afterwards. 2151 ) may accommodate only a relatively small number of

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( e.g. , two ) vertically - stacked SPADs. Photosensor 2173 can with a corresponding converging lens 2191. In this variation , therefore define an aspect ratio greater than 1 : 1 , and diffuser 9 each aperture 2157 can absorb or reflect errant light rays 2181 can spread light rays passed by the optical filter region passed by the light filter or reflected by the photosensor to 2160 according to the geometry of photosensor 2173 in further reduce crosstalk between receiver channels, thereby order to accommodate a larger sensing area per photosensor. 5 further increasing the SNR of the system . Set of apertures By incorporating more SPADs per photosensor, the dynamic 2157 and corresponding optically non - transparent stop range of the photosensor can be increased, as it less likely for regions 2159 are built on an optically transparent substrate all SPADs to be unable to detect photons ( i.e. , to be “ dead ' ) 2158 .

simultaneously. FIG . 21D is a simplified cross - sectional view diagram of In some other embodiments, photosensor 2173 includes 10 an embodiment 2103 of photosensor layer 2170 , according an array of photodetectors 2171. The height and width of the to some embodiments of the present disclosure. Photosensor receiver channel (usually defined by the diameter of colli- layer 2170 can include converging lens set 2191 , and set of mating lens 2151 ) may accommodate only a relatively small apertures 2157 , where each aperture 2157 is aligned with a number of (e.g. , two ) vertically - stacked photodiodes . Pho- corresponding converging lens 2191. Apertures 2157 and tosensor 2173 can therefore define an aspect ratio greater 15 corresponding optically non - transparent stop regions 2159 than 1 : 1 , and diffuser 2181 can spread light rays passed by are built on an optically transparent substrate 2158. In this the optical filter region 2160 according to the geometry of variation, apertures 2157 do not go all the way through to photosensor 2173 in order to accommodate a larger sensing photodetector 2171 .

area per photosensor. By incorporating more photodiodes FIG . 21E is a simplified cross - sectional view diagram of per photosensor, the dynamic range of the photosensor can 20 an embodiment 2104 of photosensor layer 2170 , according be increased , as it is unlikely for all photodiodes to be to some embodiments of the present disclosure. An addi saturated simultaneously. tional set of apertures 2157 and corresponding optically Receiver channel 2132 can additionally or alternatively non - transparent stop regions 2159 defining desired maximal include an aperture layer interposed between optical filter light cones can be positioned between lens set 2191 and region 2160 and diffuser 2181 or between the optical filter 25 photodetector 2171. Set of apertures 2157 and correspond region 2160 and photosensor 2173 , where aperture 2144 is ing non - transparent stop regions 2159 define a light cone for aligned with a corresponding collimating lens 2151. In this every lens in lens set 2191 and function to absorb or reflect variation , aperture 2144 can absorb or reflect errant light any stray light traveling along a path not encompassed by the rays passed by the light filter or reflected by the photosensor desired light cones . The apertures may be fabricated using to further reduce crosstalk between receiver channels, 30 standard semiconductor processes.

thereby further increasing SNR ( Signal to Noise Ratio ) of 4. Photosensor Layer with Converging Lens Set and the system . Spacer Structure Between the Lens Set and the Photosensor 2. Photosensor Layer with Converging Lens Set FIG . 21F is a simplified cross - sectional view diagram of FIG . 21B is a simplified cross - sectional view diagram of an embodiment 2105 of photosensor layer 2170 , according an embodiment 2101 of receiver channel 2132 , according to 35 to some embodiments of the present disclosure . Here , an some embodiments of the present disclosure. A photosensor optically non - transparent spacer structure 2163 is positioned layer 2170 of embodiment 2100 can include a photosensor between lens set 2191 and photosensor 2173 having photo 2173 formed of aa set of discrete photodetectors 2171 ( e.g. , detectors 2171 in receiver channel 2132. Optically non SPADs) and a set of inactive regions 2172 (e.g. , integrated transparent spacer structure 2163 forms a tube of substan logic ) encompassing the set of photodetectors, where each 40 tially similar or larger diameter to a collimating lens ( e.g. , photodetector is configured to detect incident photons . Pho- collimating lens 1751 shown in FIG . 17 ) and prevents any tosensor layer 2170 can also include a converging lens set light from traveling outside of receiver channel 2132 in the 2191 interposed between optical filter region 2160 and region between lens set 2191 and photosensor 2173. Opti photosensor 2173 with photodetectors 2171 , and including cally non - transparent spacer structure 2163 could be made one converging lens 2191 per discrete photodetector 2171 45 from optically non - transparent bulk media (e.g. silicon or within photosensor 2173 , where each lens of the converging polymer ).

lens set 2191 is configured to focus incident photons passed FIG . 21G is a simplified cross - sectional view diagram of by optical filter region 2160 onto a corresponding discrete an embodiment 2106 of photosensor layer 2170 , according photodetector 2171. Each converging lens can exhibit a to some embodiments of the present disclosure . Here , opti common focal length , and converging lens set 2191 can be 50 cally non - transparent spacer structure 2163 is positioned offset above photosensor 2173 by this common focal length between lens set 2191 and photosensor 2173 , and is made ( or by a distance substantially similar to this common focal from an optically non - transparent coating on an optically length ), and each converging lens can converge incident transparent substrate (e.g. black chrome on glass ) . Optically light - collimated in optical lens layer 2150 and passed by non - transparent spacer structure 2163 forms a tube of sub optical filter region 2160 onto a corresponding photode- 55 stantially similar or larger diameter to collimating lens 2151 tector 2171 in photosensor 2173 . and prevents any light from traveling outside of receiver In some embodiments, converging lens set 2191 inter- channel 2132 in the region between lens set 2191 and posed between optical filter region 2160 and photosensor photodetector 2171 .

2173 with photodetectors 2171 employs diffracting elements 5. Photosensor Layer Spacer Structure Between the Filter in addition to or replacement of refractive elements . 60 Layer and the Photosensor Layer 3. Photosensor Layer with Converging Lens Set and FIG . 21H is a simplified cross - sectional view diagram of Additional Apertures an embodiment 2107 of photosensor layer 2170 , according FIG . 21C is a simplified cross - sectional view diagram of to some embodiments of the present disclosure . Optically an embodiment 2102 of photosensor layer 2170 , according non - transparent spacer structure 2163 can be positioned to some embodiments of the present disclosure . Photosensor 65 between an optical filter layer (e.g. , any of the above layer 2170 can include a converging lens set 2191 , and a set mentioned optical filter layers ) and photosensor layer 2170 . of apertures 2157 , wherein each aperture 2157 is aligned Optically non - transparent spacer structure 2163 forms a tube

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of substantially similar or larger diameter to a collimating nant photo - cavity diodes. Each photosensor 2173 includes lens ( e.g. , collimating lens 1751 in FIG . 17 ) and prevents one or more photo - diodes 2174 ( photodetectors) along with any light from traveling outside of the receiver channel (e.g. , highly - reflective ( e.g. , partially -mirrored ) surfaces facing channel 1700 in FIG . 17 ) in the region between the optical 5 the top and bottom of the area ( the resonant cavity) . Gen filter layer and photosensor layer 2170. Optically non erally, an photodetector of a non - resonant cavity diode may transparent spacer structure 2163 can be formed by etching have a relatively low quantum efficiency. To improve the a silicon or glass wafer and may be coated with an optically percentage of photons detected by the photodetector, reso non -transparent material ( e.g. black chrome ). Alternatively, nant photo -cavity diode 2174 is used that includes : a first optically non - transparent spacer structure 2163 can be fab mirrored surface 2175 below and facing the photodetector; ricated from molded polymer. In this embodiment 2191 is directly bonded to photosensor , lensto setits 10 and a second partially mirrored surface 2176 above and 2173. Similar function in previous embodiments, lens set 2191 serves to facing cavity the photodetector, that also allows light to enter the as shown in FIG . 21K . Thus , when a photon passes focus light onto photodetectors 2171 of photosensor 2173 , through and is not detected by an photodetector of resonant rather than the inactive areas . These lenses could be inte grated directly on top of an ASIC containing photosensor 15 photo -cavitythe diode rounding 2174 , firstof resonant photodetector mirrored photo

sur 2173 in a wafer fabrication process, easing production.

6. Photosensor Layer with Conical Spacer Structures 2174 reflects the photon back toward top reflective surface FIG . 211 is a simplified cross - sectional view diagram of 2176 of the cavity and through the photodetector again , an embodiment 2108 of photosensor layer 2170 , according which may detect the photon upon its second transition to some embodiments of the present disclosure. In this 20 through the photodetector. However, if the photodetector embodiment, photosensor layer 2170 includes a set of coni- fails to detect the photon upon this second collision , the cal , optically non -transparent spacer structures 2164 that is reflection process is repeated with the second mirrored positioned between a lens set (not shown but , e.g. , lens set surface reflecting the photon back toward the photodetector, 2191 in FIGS . 21F and 21G) and photosensor 2173. Set of which again may detect the photon upon its third collision conical , optically non - transparent spacer structures 2164 can 25 with the photodetector. This process may repeat until the form tapered tubes, each with substantially similar entrance photon is detected by the photodetector of the photosensor diameter to individual lenses in the lens set, and each with or the photon escapes or is absorbed by the cavity. Resonant substantially similar exit diameter to the individual photo photo -cavity diode 2174 can thus achieve a relatively high detectors 2171 ofphotosensor 2173. Set of conical , optically rate of photon detection (i.e. approaching 100 % ) . Note that non - transparent spacer structures 2164 prevents any light 30 a particle interpretation of light is used in the preceding from traveling outside of the receiver channel in regions between the lens set and photosensor 2173 and also guide description , but consideration of wave interference effects are critical for a complete description of resonant cavity light toward the photodetectors 2171 of photosensor 2173 . photodiodes

The set of conical, optically non - transparent spacer struc photo -cavity. diode Also note that the active region of resonant 2174 may be comprised of a standard tures 2164 can be formed by etching a silicon or glass wafer 35 photodiode, an avalanche photodiode, a SPAD , or any other and may be coated with an optically non -transparent mate rial (e.g. black chrome ). Alternatively, set of conical, opti photosensor .

cally non - transparent spacer structures 2164 can be fabri FIG . 21K further shows that one or more resonant cavity cated from molded polymer. photodiodes (or “ RCPs ” ) 2174 may be combined with FIG . 21J is a simplified cross - sectional view diagram of 40 aperture 2144 , collimating lens 2151 , optical filter region an embodiment 2109 of photosensor layer 2173 , according 2160 , and any combination of the aforementioned diffusers, to some embodiments of the present disclosure. In this converging lens sets, or crosstalk mitigation structures to embodiment, photosensor layer 2173 includes a set of coni- form aa variant of receiver channel 2132. A typical RCP will cal , optically non -transparent spacer structures 2164 that is have similar wavelength sensitivity as optical filter region positioned between a lens set ( not shown but , e.g. , lens set 45 2160 and can be designed to be sensitive to a similar set of 2191 in FIGS . 21F and 21G) and photodetector 2171. The wavelengths of light as optical filter region 2160. However, inner walls of the set of conical , optically non - transparent due to fabrication or other limitations, the RCP may have spacer structures 2164 are coated with a reflective material more part -to - part variability of the center wavelength of the ( e.g. chrome) in order to further enhance the structures ' RCP's operating spectrum and thus necessitate a broader ability to act as a light pipe . Set of conical , optically 50 operating wavelength band in order for every photosensor to non - transparent spacer structures 2164 form tapered tubes , be capable of detecting photons at the system's operating each with substantially similar entrance diameter to indi- wavelength. Alternatively, it may simply be impossible to vidual lenses in the lens set , and each with substantially reliably fabricate an RCP with an operating wavelength band similar exit diameter to the individual photodetectors 2171 as narrow as the filter passband . For instance , optical filter of photosensor 2173. Set of conical , optically non - transpar- 55 region 2160 may have a passband as narrow as 0.1 nm , while ent spacer structures 2164 prevents any light from traveling the RCP may have an operating band of 10 nm . With the outside of the receiver channel in regions between the lens optical filter region 2160 on top of the RCP 2174 , the set and photosensor 2171 and also guide light toward the combined filter and RCP system has an effective operating photodetectors 2171 of photosensor 2173 . wavelength band substantially similar to optical filter region 7. Photosensor Layer with Resonant Photo -Cavity Diodes 60 2160. In addition, the RCP performance is improved when FIG . 21K is a simplified cross - sectional view diagram of sensing collimated light, as opposed to focused light, which a receiver channel 2132 including an embodiment 2110 of is provided as a result of collimating lens 2151 as depicted photosensor layer 2170 , according to some embodiments of in FIG . 21K . In this way, a system employing aperture 2144 , the present disclosure . In this embodiment, photosensor collimating lens 2151 , optical filter region 2160 , and RCP layer 2170 is configured with a resonant cavity around a 65 2174 may achieve high photon detection efficiency and photo sensitive diode to improve the photon detection effi- narrow wavelength selectivity to maximize the SNR within ciency. Each photosensor 2173 includes one or more reso- receiver channel 2132 .

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E. Hemispherical Receiver Structures 2267 , where the center of hemisphere 2267 is located at or FIG . 22A is a simplified cross - sectional view diagram of near the focal point of incoming light ( ray lines 2233 ) . The an embodiment 2200 of aa receiver channel 2232 , according center of hemisphere 2267 also corresponds to , or nearly to some embodiments of the present disclosure . Receiver corresponds to , the center of the aperture 2244. As shown in channel 2232 of embodiment 2200 can include convex 5 FIG . 22D , hemisphere 2267 can be below aperture layer hemispheres supported on an optically non - transparent 2240. In some other embodiments , hemisphere 2267 can be material. In this embodiment, an aperture layer 2240 is above aperture layer 2240 , as shown in FIG . 22E . combined with an optical filter 2261 coated on a convex FIG . 22E is a simplified cross - sectional view diagram of hemisphere 2267 , with the center of hemisphere 2267 an embodiment 2203 of a receiver channel 2232 , according located at or near the focal point of incoming light (marginal 10 to some embodiments of the present disclosure. Unlike ray lines 2233 ) . The center of hemisphere 2267 also corre- embodiment 2202 in FIG . 22D , embodiment 2215 in FIG . sponds to , or nearly corresponds to , the center of aperture 2E can be configured so that hemisphere 2267 is positioned 2244. In some embodiments, hemisphere 2267 can be below above aperture 2244 to achieve similar functionality as aperture 2244 , as shown in FIG . 22A . An advantage of the embodiment 2202 but with a more compact footprint. embodiment is that for a sufficiently well- focused cone of 15 FIGS . 22D and 22E show convex hemisphere 2267 as rays, any ray lines 2233 will pass through optical filter 2261 being coated with optical filter 2261 and imprinted on normal to the filter's surface , thereby eliminating CWL aperture layer 2240 that is supported on a rigid optically ( Center Wave Length ) shift due to variations in incident transparent layer 2245 (e.g. glass , polymer ) with aperture angle of the light ( e.g. light rays 2233 ) on optical filter 2261 , 2244 along with the corresponding optically non - transparent thereby allowing the use of very narrow bandpass (e.g. 20 stop regions 2246. As illustrated in FIGS . 22D and 22E , 850-852 nm ) filters . receiver channel 2232 includes sidewalls 2263 between This is further illustrated in FIG . 22B , which is a simpli- optically transparent layer 2245 and photosensor layer 2270 fied cross - sectional view diagram of an embodiment 2201 of with photodetectors 2271 to reduce crosstalk . Sidewalls receiver channel 2232 , according to some embodiments of 2263 can be made up of optically non - transparent material the present disclosure . Unlike embodiment 2200 in FIG . 25 or made up of optically transparent material. In addition , 22A , embodiment 2201 in FIG . 2B can be configured so that sidewalls 2263 can also be coated with reflective or absorp hemisphere 2267 is positioned above aperture 2244 to tive material. Note that, while not shown in FIGS . 22D and achieve similar functionality but with a less compact foot- 22E , there may be refraction of rays 2233 entering and print. As shown in FIG . 22B , the angle of incidence on exiting the rigid optically transparent layer 2245 . optical filter 2261 is normal for marginal ray lines 2233 (and 30 FIG . 22F is a simplified cross - sectional view diagram of all other ray lines not shown explicitly in FIG . 22B ) that pass an embodiment 2204 of aa receiver channel 2232 , according through the center of hemisphere 2267. Note that, while not to some embodiments of the present disclosure. Embodi shown in FIG . 22B or 22C , the rays will refract upon exiting ment 2204 can include a concave hemisphere 2267 made of the hemisphere structure since they are not normal to the optically transparent material (e.g. glass , polymer ) with a planar exit surface . Similarly, in FIG . 22A, there will be 35 coated optical filter 2261. Self -supported aperture layer some amount of refraction when rays enter the flat side of 2240 can overhang concave hemisphere 2267 and can be the hemispherical structure . perforated or etched with an optically non - transparent rigid As illustrated in FIGS . 22A to 22B , receiver channel 2232 material (e.g. metal film ) to form the optically non -trans

includes sidewalls 2263 between optically non - transparent parent stop regions 2246. As shown in FIG . 22F, hemisphere stop region 2246 and photosensor layer 2270 with photo- 40 2267 can be positioned below aperture layer 2240. The detectors 2271 to reduce crosstalk . Sidewalls 2263 can be center of aperture 2244 can be located at or near the focal made up of optically non - transparent material or made up of point of the incoming light ( rays 2233 ). Additionally, the optically transparent material. In addition, sidewalls 2263 center of the hemisphere 2267 can be located at or near the can also be coated with reflective or absorptive material. focal point of the incoming light ( rays 2233 ) . As illustrated A close -up view of the convex hemispherical surface is 45 in FIG . 22F, receiver channel 2232 includes sidewalls 2263 shown in FIG . 22C , which is a simplified cross - sectional between optically transparent layer 2245 and photosensor view diagram of convex hemisphere 2267 of FIGS . 22A and layer 2270 with photodetectors 2271 to reduce crosstalk . 22B . Convex hemisphere 2267 can be coated with optical Sidewalls 2263 can be made up of optically non - transparent filter 2261 and positioned on a self- supporting, optically material or made up of optically transparent material. In non - transparent stop region 2246 such as metal , silicon , 50 addition , sidewalls 2263 can also be coated with reflective or polymer etc. In some embodiments where the convex hemi- absorptive material.

spherical surfaces of the micro - optic channels are used for FIG . 22G is a simplified cross - sectional view diagram of hyperspectral imagers , optical filter 2261 can be configured an embodiment 2205 of receiver channel 2232 , according to to be non -uniform . For example, optical filter 2261 can be a some embodiments of the present disclosure . Unlike graduated filter increasing gradually or in a step -wise man- 55 embodiment 2204 in FIG . 22F, embodiment 2205 in FIG . ner in one direction (e.g. , the thickness direction ) that 2G can be configured so that hemisphere 2267 is positioned different micro -optic channels have different optical filter above aperture 2244 to achieve similar functionality as layers that have different thicknesses. This allows different embodiment 2204 , but embodiment 2204 may have a more micro - optic channels to measure a different range of wave compact footprint.

lengths as discussed herein with respect to FIGS . 3A and 3B . 60 FIG . 22H is a simplified cross - sectional view diagram of FIG . 22D is a simplified cross - sectional view diagram of an embodiment 2206 of receiver channel 2232 , according to an embodiment 2202 of aa receiver channel 2232 , according some embodiments of the present disclosure . Receiver chan to some embodiments of the present disclosure . Receiver nel 2232 of embodiment 2206 can include a concave hemi channel 2232 of embodiment 2202 can include convex sphere 2267 and aperture layer 2240 supported by a rigid , hemisphere 2267 supported on a rigid optically transparent 65 optically transparent layer 2245. In some embodiments , layer. In this embodiment, aperture layer 2240 is combined concave hemisphere 2267 can be below the aperture layer with optical filter 2261 and coated on convex hemisphere 2240 as shown in FIG . 22H . Concave hemisphere 267 can

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be made of optically transparent material ( e.g. glass , poly- photodetectors 2371. As shown in FIG . 23E , the BMLL can mer) with aa coated optical filter 2261. Aperture layer 2240 be formed of a single micro - lens 2391 for guiding divergent with optically transparent aperture 2244 and corresponding light to photodetector 2371 .

optically non - transparent stop regions 244 is supported by Embodiments 2302 and 2303 in FIGS . 23D and 23E each optically transparent layer 2245 on both top and bottom 5 include a convex hemisphere 2367 supported on a rigid sides of aperture layer 2240. The center of aperture 2244 is optically transparent layer 2345. In these illustrations, an located at or near the focal point of the incoming light ( rays aperture coated on layer 2340 is combined with an optical filter 2361 hemisphere 2367 , where the center of hemisphere 2233 ) . Additionally, the center of concave hemisphere 2267 2367 is located at or near the focal point of incoming light is located at or near the focal point of the incoming light ( rays 2233 ). As illustrated in FIG. 22H, receiver channel 10 can (marginal ray lines 2333 ). The center of hemisphere 2367 also correspond to , or nearly correspond to , the center of 2232 includes sidewalls 2263 between optically transparent aperture 2344. Convex hemisphere 2367 can be coated with layer 2245 and photosensor layer 2270 with photodetectors optical filter 2361 and imprinted on aperture layer 2340 that 2271 to reduce crosstalk . Sidewalls 2263 can be made up of is supported on rigid optically transparent layer 2345 ( e.g. optically non -transparent material or made up of optically 15 layer formed of glass, polymer) and the corresponding transparent material. In addition, sidewalls 2263 can also be optically non - transparent stop regions 2346. As illustrated in coated with reflective or absorptive material. FIGS . 23D and 23E , receiver channel 2332 includes side FIG . 221 is a simplified cross - sectional view diagram of walls 2363 between optically transparent layer 2345 and an embodiment 2207 of receiver channel 2232 , according to photosensor layer 2370 to reduce crosstalk . Sidewalls 2363 some embodiments of the present disclosure . Unlike 20 can be made up of optically non - transparent material or embodiment 2206 in FIG . 22H , embodiment 2207 in FIG . 21 made up of optically transparent material. In addition , can be configured so that hemisphere 2267 is positioned sidewalls 2363 can also be coated with reflective or absorp above aperture 2244 to achieve similar functionality as tive material.

embodiment 2206 . G. Additional Exemplary Receiver Channels F. Bottom Micro -Lens Layer 25 It is to be appreciated that aa receiver channel is a structure FIG . 23A is a simplified cross - sectional view diagram of at the micro - optic level, e.g. , a micro -optic receiver channel an embodiment 2300 of a receiver channel 2332 , according including discussed above , that can be formed from multiple layers to some embodiments of the present disclosure . Receiver layer belowonetheoraperture more of an aperture layer, an optical lens layer, an optical filter layer below channel 2332 of embodiment 2300 can include a Bottom

Micro - Lens Layer ( BMLL ) , which consists of one or more below all the other layers. Eachlayer 30 the aperture and optical lens , and a photosensor layer micro - lenses 2391 that are configured to guide divergent in various ways to mitigate cross -talklayer such

can be configured i.e. , exposing stray light rays into active portion of the photosensors. The BMLL light to adjacent receiver channels, as discussed herein with performs ray angle correction to guide light from dissimilar respect to FIGS. 17-23E . Various examples of receiver angles into evenly spaced photosensors . Ray angle correc 35 channels are discussed above with respect to FIGS . 17 , tion can be achieved by controlling the lateral offset between 22A - 221 , and 23A - 23E . Two other examples of receiver lens center and the photosensor center, tilting of the lens , or channels according to the present disclosure are illustrated in adjusting the form of the lens . A better illustration of this FIGS . 24 and 25. Embodiments of the present disclosure are operation can be seen in FIG . 23B . not limited to the particular receiver channels described FIG . 23B is a simplified cross - sectional view diagram of 40 herein . Instead, based on the present disclosure a person of a close-up view of the propagation of light during ray angle skill in the art will appreciate that in other embodiments a correction by a BMLL , according to some embodiments of receiver channel according to the disclosure can include , the present disclosure . As illustrated , the pitch of the micro- among other options , an aperture layer as described above optics is either not constant or is not equal to the pitch of with respect to any of FIGS . 18A - 18D or 19A - 19D , a filter lenses 2391 in order to steer the divergent rays (2333 ) to 45 layer as described above with respect to any of FIGS . active portions of photodetectors 2371 in the photosensor 20A - 20G , and / or a photosensor layer as described above layer. With reference back to FIG . 23A , each micro - lens with respect to any of FIGS . 21A - 21K . 2391 can be positioned to correspond with a respective FIG . 24 is a simplified cross - sectional view diagram of an photodetector 2371 . exemplary embodiment of a receiver channel 2400 , accord FIG . 23C is a simplified cross - sectional view diagram of 50 ing to some embodiments of the present disclosure . Receiver an embodiment 2301 of a receiver channel 2332 , according channel 2400 can include an aperture layer 2440 composed to some embodiments of the present disclosure . Receiver of first and second apertures 2444 , each formed in respective channel 2332 of embodiment 2301 can include a single optically non - transparent layers 2446a and 2446b . First micro - lens 2391 , instead of a plurality of micro - lenses as and / or second apertures 2444 can be formed of void space shown in FIG . 23A . Single micro - lens 2391 can be posi- 55 defined by openings within layers 2446a and 2446b in some tioned over and centered to a single photodetector 2371 . embodiments , while first and /or second apertures 2444 can Micro - lens 2391 can be configured to guide light to single be formed by optically transparent materials in some other photodetector 2371 embodiments. First and second optically non - transparent FIGS . 23D and 23E is a simplified cross - sectional view layers 2446a and 2446b can be supported by an optically diagram of embodiments 2302 and 2303 , respectively, of a 60 transparent substrate 2445 sandwiched between first and receiver channel 2332 , according to some embodiments of second optically non -transparent layers 2446a and 2446b . the present disclosure . Receiver channel 2332 of embodi- Receiver channel 2400 can also include an optical lens ment 2302 can include a BMLL positioned on the underside layer 2450 disposed below aperture layer 2440. Optical lens of an optically transparent layer 2345 supporting aperture layer 2450 can include a collimating lens 2451 and an layer 2340 and hemisphere 2367 with optical filter 2361 65 optically non -transparent spacer structure 2456. Collimating coated . As shown in FIG . 23D , the BMLL can be formed of lens 2451 can be separated from aperture layer 2440 by multiple lenses 2393 for guiding divergent light to multiple optically non -transparent spacer structure 2456. In some

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embodiments, optically non -transparent spacer structure layer 2540 and optical lens layer 2550. Aperture layer 2540 , 2456 forms a tube having a circumference that surrounds optical lens layer 2550 , and optical filter layer 2560 can have collimating lens 2451 and extends toward aperture layer the same construction and function as corresponding com 2440. Optically non -transparent spacer structure 2456 can ponents in FIG . 24 .

be formed of an optically reflective or absorptive material 5 Receiver channel 2500 can also include a photosensor that prevents any light from traveling outside of receiver layer 2570 positioned immediately below optical filter layer channel 2400 in the region between aperture layer 2440 and 2560. In some embodiments, photosensor layer 2570 of collimating lens 2451 . embodiment 2400 can include an optically non -transparent In addition to aperture layer 2440 and optical lens layer spacer structure 2563 , a converging lens set 2591 , and a 2450 , receiver channel 2400 can further include an optical 10 photosensor 2573. Unlike converging lens set 2491 of filter layer 2460 positioned directly below optical lens layer receiver channel 2400 in FIG . 24 , converging lens set 2591 2450. Optical filter layer 2460 can include two optical filters of receiver channel 2500 can be positioned directly on at top 2461 sandwiching an optically transparent substrate 2465 surface of photosensor 2573 instead of directly on an that structurally supports optical filters 2461. Optical filter underside of optical filter layer 2560. Furthermore , optically layer 2460 can contain any number and type of optical filters 15 non - transparent spacer structure 2563 can be formed of an 2461 on any number of substrates 2065. For instance, one of optically non -transparent material ( e.g. , black chrome) optical filters 2461 can be a bandpass filter and be positioned coated on an optically transparent layer, such as a silicon or on either on top of or directly below optically transparent glass substrate, instead of being a solid optically non substrate 2465 that blocks all of the incident light for a transparent structure , e.g. , optically non - transparent spacer defined set of wavelengths ( e.g. 900-945 nm and 950-995 20 structure 2463 of receiver channel 2400 in FIG . 24. Lens set nm ). The other optical filter 2461 placed on the opposite side 2591 serves to focus light onto photodetectors 2571 of of optically transparent substrate 2465 can be a different photosensor 2573 , rather than inactive areas 2572 . filter, such as a wide spectrum blocking filter ( except for the By implementing a receiver channel according to any of region covered by the bandpass filter ), for example covering embodiments 2400 and 2500 , errant light can be prevented 200-915 nm and 980-1600 nm . The bandpass filter and 25 from exposing on adjacent receiver channels, thereby blocking filter are designed such that there is no leakage in improving the accuracy of each photosensor's ability to the transition region between the two filters. However, the capture photons for imaging.

filters could be two edge pass filters designed to work in VI . Micro Optical Receiver Channel Array Variations conjunction as a bandpass filter or any other type of filter. According to some embodiments of the present disclo Immediately below optical filter layer 2460 can be a 30 sure , micro - optical receiver channels can be organized in an photosensor layer 2470. In some embodiments, photosensor array. The array can have various dimensions according to layer 2470 of embodiment 2400 can include an optically design . For instance, an array of micro -optical receiver non - transparent spacer structure 2463 positioned between a channels can be arranged in a MxN array where Mand N are converging lens set 2491 and a photosensor 2473. Photo- equal to or greater than 1. Accordingly, micro -optical sensor 2473 can be formed of a set of discrete photodetectors 35 receiver channels can be one- and two - dimensional arrays, 2471 ( e.g. , SPADs) positioned between a set of inactive as will be discussed furthered herein with respect to FIGS . regions 2172 ( e.g. , integrated logic ) in an alternating 26-30 , which illustrate different embodiments of micro arrangement, where each discrete photodetector is config- optical receiver channel arrays where each dot represents a ured to detect incident photons . Converging lens set 2491 micro - optical receiver channel. As aforementioned herein , can be interposed between optical filter layer 2460 and 40 each receiver channel can include a plurality of layers photosensor 2473 with photodetectors 2471 , and including stacked upon each other. Thus, it can be appreciated that

one converging lens 2491 per discrete photodetector 2471 when arranged in an array, each micro - optic receiver chan within photosensor 2173 , where each lens of the converging nel is part of a monolithic layer composed of the individual lens set 2491 is configured to focus incident photons passed elements reproduced many times in the MxN arrangement, by optical filter layer 2460 onto a corresponding discrete 45 e.g. , an MxN aperture layer array , an MxN micro lens layer photodetector 2471. Each converging lens can exhibit a array , and an MxN photosensor layer array . When bonded common focal length , and converging lens set 2491 can be together, these array layers create a monolithic multi -chan offset above the sensing plane of the photosensor by this nel micro optical receiver array .

common focal length ( or by a distance substantially similar FIG . 26 is a simplified illustration of an exemplary to this common focal length ), and each converging lens can 50 micro - optical receiver array 2600 , according to some converge incident light - collimated in optical lens layer embodiments of the present disclosure . Micro -optical 2450 and passed by optical filter layer 2460 onto one receiver array 2600 is configured as a linear (Mx1 ) array , corresponding photodetector 2471 in photosensor 2473 . specifically a 16xl array . This layout can achieve a high Optically non - transparent spacer structure 2463 forms a tube resolution (e.g. 16x1024 ) as the implementation is amenable of substantially similar or larger diameter to a collimating 55 to scanning the array in one dimension.As an example, for lens 2451 and prevents any light from traveling outside of a receiver channel pitch of 500 microns the layout illustrated receiver channel 2400 in the region between lens set 2491 can be implemented in a chip of a size that is approximately and photosensor 2473. Optically non - transparent spacer 500 microns by 8000 microns .

structure 2163 could be made from optically non - transparent FIG . 27 is a simplified illustration of an exemplary bulk media (e.g. silicon or polymer ). 60 micro - optical receiver array 2700 , according to some Another exemplary embodiment of a receiver channel is embodiments of the present disclosure . Micro -optical shown in FIG . 25. FIG . 25 is a simplified cross - sectional receiver array 2700 is configured as a rectangular ( MXN) view diagram of an exemplary receiver channel 2500 , array, specifically a 16x32 array . Thus, for a receiver channel according to some embodiments of the present disclosure. pitch of 500 microns the layout illustrated can be imple Receiver channel 2500 can include an aperture layer 2540 , 65 mented in a chip of size 8,000 microns by 12000 microns . an optical lens layer 2550 disposed below aperture layer FIG . 28 is a simplified illustration of an exemplary 2540 , and an optical filter layer 2560 below both aperture micro - optical receiver array 2800 , according to some

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embodiments of the present disclosure . Micro -optical sponding aperture and pass the collimated light rays receiver array 2800 is configured as an MxN staggered into its corresponding photosensor. array . In this illustration , receiver channels 2832 are laid out 2. The optical system set forth in claim 1 wherein the in a 16x4 staggered array. This layout can achieve a high non -uniform optical filter comprises a graduated optical resolution (e.g. 64x1024 ) as the implementation is amenable 5 filter.

to sweeping. For aa receiver channel pitch of 500 microns the 3. The optical system set forth in claim 2 wherein the layout illustrated in FIG . 28 can be implemented in a chip of graduated optical filter gradually increases in thickness in a size that is approximately 2000 microns by 8375 microns . one dimension .

FIG . 29 is a simplified illustration of an exemplary 4. The optical system set forth in claim 2 wherein the micro - optical receiver array 2900 , according to some 10 graduated optical filter increases in thickness in a step -wise embodiments of the present disclosure . Micro -optical fashion in one dimension such that each channel has a receiver array 2900 is configured as a warped linear (Mx1 ) constant optical filter layer thickness, but wherein the thick array . In this embodiment, the spacing between receiver nesses for different micro - optic channels are different. channels 2932 is uneven . Receiver channels near the center, 5. The optical system set forth in claim 1 wherein the shown as 2932-01 , are placed close together (e.g. 400 15 array of photosensors comprises an array of photodetectors microns apart ), while the exterior channels , shown as 2932- with each photodetector comprising an array of single 02 , are placed farther apart ( e.g. , greater than 400 microns photon avalanche detectors (SPADs ). apart ), or vice versa . This layout has an advantage of being 6. The optical system set forth in claim 1 wherein each able to allow for correction of the distortion curve of a lens channel includes an aperture from the plurality of discrete (i.e. the angles between the receiver channel fields of view 20 apertures, and a photosensor in the array of photosense nsors .

are evenly spaced in the object space) . The arrangement 7. The optical system set forth in claim 1 wherein the lens shown in FIG . 29 can be used to achieve a high resolution for each channel is configured as a hemisphere positioned ( e.g. 16x1024 ) as the implementation is amenable to sweep- along a path of light from the bulk receiver optic , wherein ing . For an average receiver channel pitch of 500 microns the optical filter is coated on a curved surface of the lens . the layout illustrated can be implemented in a chip of a size 25 8. The optical system set forth in claim 1 wherein the that is approximately 500 microns by 8000 microns . photosensor in each channel comprises a plurality of single In some embodiments, the receiver channels can be photon avalanche detectors (SPADs ).

configured in a MxN warped array (where N 1) . In such 9. An optical system , comprising: embodiments, the receiver channels in the center are placed bulk receiver optic configured to receive light rays further from each other in both the x and y direction than the 30 originating from a field external to the optical system ; exterior receiver channels . This corrects for another possible and form of lens distortion . an optical assembly having a plurality of micro -optic FIG . 29 is a simplified illustration of an exemplary receiver channels defining a plurality of discrete , non micro - optical receiver array 2900 , according to some overlapping fields of view in the field , the optical embodiments of the present disclosure . Micro -optical 35 assembly comprising:

receiver array 2900 is configured in an arbitrary pattern. This an aperture layer having a plurality of discrete apertures layout arrangement has the advantage of being able to arranged along a focal plane of the bulk receiver accommodate lens distortion, to make adjustments to com optic ;

pensate for any timing or routing variations, and also to a plurality of lenses ;

match an arbitrary pattern from an illumination source . 40 an array of photosensors disposed behind the aperture Although the present disclosure has been described with layer; and respect to specific embodiments, it will be appreciated that a non -uniform optical filter layer configured to allow the present disclosure is intended to cover all modifications different micro - optic channels to measure different and equivalents within the scope of the following claims . ranges of wavelengths;

45 wherein each channel includes an aperture from the

What is claimed is : plurality of discrete apertures, a lens from the plu 1. An optical system , comprising: rality of lenses and a photosensor in the array of a bulk receiver optic configured to receive light rays photosensors, the photosensor comprising a plurality originating from a field external to the optical system ; of single -photon avalanche detectors ( SPADs ); and 50 wherein the lens for each channel collimates lights rays an optical assembly having a plurality of micro -optic received through its corresponding aperture and receiver channels defining a plurality of discrete , non passes the collimated light rays into its correspond overlapping fields of view in the field , the optical ing photosensor; and assembly comprising: each channel further comprises a second plurality of an aperture layer having a plurality of discrete apertures 55 lenses that corresponds in number to the plurality of arranged along a focal plane of the bulk receiver SPADs and wherein each lens in the second plurality optic; of lenses focuses incident photons received at the an array of photosensors disposed behind the aperture photosensor on an individual SPAD in the plurality layer; and of SPADs in the channel.

a non - uniform optical filter layer configured to allow 60 10. An optical system , comprising:

different micro -optic channels to measure different a bulk receiver optic configured to receive light rays ranges of wavelengths; originating from a field external to the optical system ; wherein the optical assembly further comprises a plu and rality of lenses , each channel further including a lens an optical assembly having a plurality of micro - optic from the plurality of lenses , and wherein the lens for 65 receiver channels defining a plurality of discrete, non each channel is axially aligned with and configured overlapping fields of view in the field , the optical to collimate lights rays received through its corre assembly comprising:

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an aperture layer having a plurality of discrete apertures 14. The optical system set forth in claim 13 wherein the arranged along a focal plane of the bulk receiver graduated optical filter gradually increases in thickness in optic ; one dimension .

an array of photosensors disposed behind the aperture 5 graduated 15. The optical system set forth in claim 13 wherein the layer; and optical filter increases in thickness in a step - wise fashion in one dimension such that each channel has a a non - uniform optical filter layer configured to allow constant optical filter layer thickness, but wherein the thick different micro -optic channels to measure different nesses for different micro - optic channels are different. ranges of wavelengths; 16. An optical system , comprising : wherein the optical assembly comprises a monolithic 10 a bulk receiver optic configured to receive light rays ASIC constructed on a common substrate , within originating from a field external to the optical system ; which the array of photosensors are fabricated , and and the separate layers for the aperture layer, a plurality an optical assembly having a plurality of micro -optic of lenses , and the filter layer are formed on the receiver channels defining a plurality of discrete , non monolithic ASIC such that they become part of the 15 overlapping fields of view in the field , the optical monolithic structure of the ASIC . assembly comprising:

11. The optical system set forth in claim 10 wherein each a monolithic ASIC including a processor, a memory, of the separate layers for the aperture layer, the plurality of and a plurality of photosensors fabricated in the lenses , the filter layer and the array of photosensors is ASIC ;

bonded to its adjacent layer. an aperture layer having a plurality of discrete apertures 12. An optical system comprising:

arranged along a focal plane of the bulk receiver a bulk receiver optic configured to receive light from a optic , the array of photosensors disposed behind the field external to the optical system ; aperture layer;

an aperture layer disposed behind the bulk optic and a plurality of lenses positioned between the aperture including a plurality of apertures located at a focal 25 layer and the array of photosensors; and plane of the bulk optic ; a non -uniform optical filter layer configured to allow a lens layer including a plurality of collimating lenses different micro -optic channels to measure different having a focal length , the lens layer disposed behind the ranges of wavelengths, wherein the aperture layer, aperture layer and separated from the aperture layer by plurality of lenses , and non -uniform optical filter the focal length ; 30 layer are formed on the ASIC such that they form a non - uniform optical filter layer behind the lens layer; part of the monolithic structure of the ASIC . and 17. The optical system set forth in claim 16 wherein the a photosensor layer including a plurality of photosensors ; micro - optic receiver channels are configured such that each wherein the aperture layer, lens layer, non -uniform optical micro a - optic receiver channel is paired with a light emitter of plurality of light emitters.

filter layer and photosensor layer are arranged to form 35 18. The optical a plurality of micro -optic channels defining a plurality non -uniform opticalsystem filter set forth in claim 16 wherein the comprises a graduated optical of discrete , non -overlapping fields of view in the field filter.

with each micro - optic channel in the plurality of micro 19. The optical system set forth in claim 18 wherein the optic channels including an aperture from the plurality graduated optical filter gradually increases in thickness in of apertures, a lens from the plurality of lenses, a filter 40 one dimension .

from the filter layer, and a photosensor from the plu 20. The optical system set forth in claim 1 wherein a rality of photosensors and being configured to commu sensing nicate light incident from the bulk receiver optic to the sensors isarealarger of each photosensor in the plurality of photo than an area of its corresponding aperture photosensor of the micro - optic channel; and wherein the non -uniform optical filter layer is configured 45 21. The optical apertures in the plurality of system

set forth in claim 12 wherein a to allow different micro - optic channels to measure sensing area of each photosensor in the array of photosen different ranges of wavelengths. sors is larger than an area of its corresponding aperture in the 13. The optical system set forth in claim 12 wherein the plurality of apertures.

non - uniform optical filter comprises a graduated optical filter.