Polarization sorting metasurface microlens array device

Abstract

Systems and methods including polarization sorting metasurface microlens array devices are disclosed herein. In certain embodiments, a polarization imaging device is provided. The polarization imaging device includes a light source of image light, a metasurface lenslet array including a plurality of repeating metasurface lenslets, the plurality of repeating metasurface lenslets being configured to diffract the image light into a first polarization in a first direction and into the second polarization in a second direction, and an image sensor positioned in the optical path of the first polarization and the second polarization, the image sensor including a plurality of image sensing units having a first image sensing unit positioned to sense the first polarization and a second image sensing unit positioned to sense the second polarization.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of and priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 63 / 362,285, filed March 31, 2022, entitled "POLARIZATION SORTED METASURFACE MICROLENS ARRAY DEVICE," the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0002] FIELD OF THEINVENTION The present invention relates generally to polarization sorting devices, and more particularly to polarization sorting devices that include polarization sorting metasurface microlens arrays and methods of producing polarization sorting devices. [Background technology]

[0003] Metasurface elements are diffractive optical elements in which the individual waveguide elements have subwavelength spacing and typically have a planar profile. Recently, metasurface elements have been developed for applications in the UV-IR band (300-10,000 nm). Compared to conventional refractive optics, metasurface elements abruptly introduce a phase shift into the light field. This allows metasurface elements to have thicknesses on the order of the wavelength of light they are designed to operate with, whereas conventional refractive surfaces have thicknesses of 10 to 100 times (or more) the wavelength of light they are designed to operate with. Furthermore, metasurface elements may not have variations in height in the components, and therefore they can shape light without any curvature as required for refractive optics. Compared to conventional Diffractive Optical Elements (DOEs), such as binary diffractive optics, metasurface elements have the ability to impart a wide range of phase shifts to the incident light field. At a minimum, metasurface elements can have phase shifts between 0 and 2π with at least five different values ​​from that interval, whereas binary DOEs can only impart two different phase shift values ​​and are often limited to phase shifts of either 0 or 1π. Compared to multilevel DOEs, metasurface elements do not require variations in the height of the components along the optical axis, and only the in-plane shape of the metasurface element features varies. Summary of the Invention [Means for solving the problem]

[0004] In one aspect, the technology described herein relates to a polarized imaging device including a metasurface lenslet array including a plurality of metasurface lenslets configured to diffract image light with an intensity proportional to a first polarization in a first direction and with an intensity proportional to a second polarization in a second direction, and an image sensor positioned in an optical path of the first polarization and the second polarization, the image sensor including a plurality of image sensing units having a first image sensing unit positioned to sense the first polarization and a second image sensing unit positioned to sense the second polarization.

[0005] In one aspect, the multiple image sensing units are different pixels and / or areas of an image sensor.

[0006] In one aspect, the multiple image sensing units are different pixels and / or areas of multiple image sensors.

[0007] In one aspect, the plurality of metasurface lenslets further includes a plurality of second metasurface lenslets interspersed between the first metasurface lenslets and configured to diffract the image light with an intensity proportional to the third polarization in a third direction and an intensity proportional to the fourth polarization in a fourth direction, and the plurality of image sensing units further includes a third image sensing unit positioned to sense the third polarization and a fourth image sensing unit positioned to sense the fourth polarization.

[0008] In one aspect, the first polarization and the third polarization are the same polarization, and the second polarization and the fourth polarization are the same polarization.

[0009] In one aspect, the first metasurface lenslet is further configured to diffract the image light with an intensity proportional to the third polarization in a third direction and with an intensity proportional to the fourth polarization in a fourth direction, and the plurality of image sensing units further includes a third image sensing unit positioned to sense the third polarization and a fourth image sensing unit positioned to sense the fourth polarization.

[0010] In one aspect, the first metasurface lenslet is further configured to pass zero-order light in a third direction.

[0011] In one aspect, the third direction is different from the first direction and the second direction.

[0012] In an aspect, the plurality of image sensing units further includes a third image sensing unit configured to sense zero-order light.

[0013] In one aspect, the third direction is the same as the first direction.

[0014] In one aspect, the polarized imaging device further includes one or more refractive lenses, and the metasurface lenslet array is positioned between the refractive lenses and the image sensor.

[0015] In one aspect, the first polarization and the second polarization are different polarizations, and the first polarization and the second polarization are selected from the group consisting of linear polarization, oblique polarization, elliptical polarization, and circular polarization.

[0016] In one aspect, the polarized imaging device further includes a microlens array, and the metasurface lenslet array includes a polarizing metasurface.

[0017] In one aspect, the microlens array is configured to separate the image light into different pixels, and the polarizing metasurface is configured to diffract a first polarization in a first direction and a second polarization in a second direction.

[0018] In one aspect, the polarizing metasurface overlaps a microlens in a microlens array, and microlenses in the microlens array that do not overlap the polarizing metasurface pass the undiffracted light to an image sensor, and the image sensor is configured to sense the undiffracted light to measure the intensity of the undiffracted light.

[0019] In one aspect, the microlens array is a planar microlens array layer.

[0020] In one aspect, the microlens array and the polarizing metasurface are located on a single substrate.

[0021] In one aspect, the primary image plane is configured above a surface of a single substrate opposite the image sensor.

[0022] In one aspect, the primary image surface is constructed within a single substrate.

[0023] In one aspect, the microlens array includes metasurface elements.

[0024] In one aspect, the metasurface element is configured to receive a Chief Ray Angle (CRA) that varies across an imaging pupil of the polarized imaging device and collimate the light passing through each microlens.

[0025] In one aspect, the metasurface elements of the microlens array are configured to provide a refractive microlens effect.

[0026] In one aspect, the microlens array comprises a conventional refractive microlens array.

[0027] In one aspect, the microlens array includes a combination of at least one conventional refractive microlens and at least one metasurface element.

[0028] In one aspect, the polarized imaging device further includes a color filter positioned above or below the metasurface lenslet array.

[0029] In one aspect, the color filter is positioned above the metasurface lenslet array and filters light into different colors, each of the different colors corresponding to a different metasurface lenslet of the plurality of first metasurface lenslets, and the metasurface lenslets receive the color filtered light from the color filter.

[0030] In one aspect, a color filter is positioned below the metasurface lenslet array to filter the diffracted first and second polarizations.

[0031] In one aspect, the color filters include different areas that filter different wavelengths of light.

[0032] In one aspect, the plurality of first metasurface lenslets are spaced apart on the cover substrate.

[0033] In one aspect, the first spaced apart metasurface lenslets are configured to output light onto a range of color filters that output light of the same color.

[0034] In one aspect, the first spaced apart metasurface lenslet outputs light onto a region of the color filter that outputs green light and a gap between the regions of the color filter that outputs red or blue light.

[0035] In one aspect, the color filter includes different areas that output red, green, or blue light, and an area that outputs monochrome or near-infrared light, and the plurality of first metasurface lenslets are spaced apart on the cover substrate, the spaced apart first metasurface lenslets output light to the areas of the color filter that output monochrome or near-infrared light.

[0036] In one aspect, the polarized imaging device further includes a microlens array having a plurality of individual microlenses that output collimated light to the metasurface lenslet array.

[0037] In one aspect, the multiple separated microlenses are positioned between adjacent image sensing units such that light from the multiple separate microlenses is diffracted by the multiple first metasurface lenslets in opposite oblique directions to the adjacent image sensing units.

[0038] In one aspect, the plurality of repeating metasurface lenslets further includes a plurality of second metasurface lenslets configured to diffract the first polarization in a second direction and diffract the second polarization in the first direction, and the first image sensing unit is further positioned to sense the first polarization diffracted from the plurality of second metasurface lenslets.

[0039] In one aspect, each of the plurality of separated microlenses is centered with one of the plurality of first metasurface lenslets such that a first polarization is transmitted through one of the plurality of first metasurface lenslets onto a first image sensing unit and a second polarization is diffracted in a second direction onto a second image sensing unit.

[0040] In one aspect, the first polarization and the second polarization are orthogonal linear, circular, elliptical, or arbitrary polarizations.

[0041] In one aspect, the plurality of first metasurface lenslets are spaced apart with non-diffractive sections between adjacent first metasurface lenslets.

[0042] In one aspect, a plurality of metasurface lenslets, a plurality of image sensing units configured to sense a first polarization and a second polarization, are positioned between image sensing units of an image sensor configured to sense red light, green light, or blue light.

[0043] In one aspect, the plurality of first metasurface lenslets are configured to diffract light to a plurality of image sensing units configured to sense a first polarization and a second polarization, and to an image sensing unit configured to sense red light, green light, or blue light.

[0044] In one aspect, the plurality of image sensing units configured to sense the first polarized light and the second polarized light are further configured to sense monochromatic light or near infrared light.

[0045] In one aspect, the image sensor is a Complementary Metal-Oxide-Semiconductor (CMOS) image sensor, a charge-coupled device sensor, a silicon diode sensor, a cadmium sulfide sensor diode, an RGB sensor, an indirect time of flight (iToF) sensor, or a direct time of flight (dToF) sensor.

[0046] In one aspect, the technology described herein relates to a method of producing a polarization imaging device, the method including providing an image sensor wafer, depositing a spacer layer on the image sensor wafer, depositing a metasurface layer on the spacer layer, and patterning the metasurface layer to form individual metasurfaces in the spacer layer.

[0047] In one aspect, the method further includes depositing an encapsulation layer directly onto the individual metasurfaces.

[0048] In one aspect, the method further includes planarizing the encapsulation layer such that the encapsulation layer is in the same horizontal plane as the individual metasurfaces.

[0049] In certain aspects, the method further includes forming one or more top layers on the encapsulation layer and / or the individual metasurfaces.

[0050] In one aspect, the technology described herein relates to a method of producing a polarization imaging device, the method including providing an image sensor wafer, providing a metasurface substrate including individual metasurfaces, and depositing a spacer layer on the imaging sensor wafer and / or the individual metasurfaces of the metasurface substrate.

[0051] In one aspect, the method further includes bonding the metasurface substrate to an image sensor wafer.

[0052] In one aspect, the metaphase substrate comprises a transparent substrate.

[0053] In one aspect, the method further includes removing the metasurface substrate such that the individual metasurfaces remain attached to the image sensor wafer.

[0054] In one aspect, removing the metasurface substrate includes grinding, lapping, wet chemical etching, and / or dry chemical etching the metasurface substrate.

[0055] In one aspect, the method further includes singulating the metasurface substrate into separate metasurface dies, bonding at least one of the metasurface dies to an image sensor wafer, and singulating the image sensor wafer into image sensor dies each having a bonded metasurface die.

[0056] In one aspect, the technology described herein relates to a method of producing a polarization imaging device, the method including providing a CMOS Image Sensor (CIS) wafer, positioning a first plurality of spacers on the CIS wafer, providing a first carrier wafer, positioning a first adhesive layer on the first carrier wafer, contacting the first plurality of spacers with the first adhesive layer such that adhesive is applied on top of the first plurality of spacers, providing a nanopillar substrate having a plurality of nanopillars, positioning a second plurality of spacers on the nanopillar substrate, providing a second carrier wafer, positioning a second adhesive layer on the second carrier wafer, contacting the second plurality of spacers with the second adhesive layer such that adhesive is applied on top of the second plurality of spacers, simultaneously contacting the adhesive of the second plurality of spacers with the CIS wafer and contacting the adhesive of the first plurality of spacers with the nanopillar substrate, and adhering the CIS wafer and the nanopillar substrate together.

[0057] In one aspect, after the first plurality of spacers is contacted with the first adhesive layer such that the adhesive is applied to the tops of the first plurality of spacers, the adhesive is only on the tops of the first plurality of spacers and not in the areas between the first plurality of spacers.

[0058] In one aspect, after the second plurality of spacers is contacted with the second adhesive layer such that the adhesive is applied to the tops of the second plurality of spacers, the adhesive is only on the tops of the second plurality of spacers and not in the areas between the second plurality of spacers.

[0059] In one aspect, the first plurality of spacers includes pairs of spacers that form channels sized to accommodate spacers of the second plurality of spacers.

[0060] In one aspect, the first and second plurality of spacers interdigitate such that one of the second plurality of spacers is positioned in one of the channels formed by the pair of spacers.

[0061] In one aspect, the first plurality of spacers form a plurality of rectangular shapes on the CIS wafer.

[0062] In one aspect, the interior of the rectangular shape forms an imaging area.

[0063] In one aspect, the second plurality of spacers forms a grid pattern on the nanopillar substrate.

[0064] In one aspect, the first plurality of spacers and the second plurality of spacers form air gaps between the plurality of nanopillars and the CIS wafer.

[0065] In one aspect, the technology described herein relates to a method of producing a polarization imaging device, the method including providing a CMOS image sensor (CIS) wafer having bonding pads, depositing a first dielectric layer on the CIS wafer and the bonding pads, planarizing the first dielectric layer, providing a nanopillar substrate having a plurality of nanopillars, depositing a second dielectric layer on the plurality of nanopillars, planarizing the second dielectric layer, contacting the first dielectric layer and the second dielectric layer such that they bond together to form a combined dielectric layer, removing the nanopillar substrate to expose the plurality of nanopillars, partially etching the combined dielectric layer to expose the bonding pads, and forming a conductive layer electrically connected to the bonding pads through the combined dielectric layer.

[0066] In one aspect, the first dielectric layer and the second dielectric layer are silicon dioxide layers.

[0067] In one aspect, deposition of the first and second dielectric layers is performed with a tetraethylorthosilicate (TEOS) process.

[0068] In one aspect, the TEOS process is a Plasma Enhanced TEOS (PETEOS) process.

[0069] In one aspect, the planarization of the first and second dielectric layers is performed with a Chemical Mechanical Polishing (CMP) process.

[0070] In one aspect, the removal of the nanopillar substrate is accomplished by a grinding, etching, or chemical mechanical polishing (CMP) process.

[0071] In one aspect, partially etching the combined dielectric layers includes patterning the combined dielectric layers and etching the combined dielectric layers to expose the bond pads.

[0072] In one aspect, the method further includes growing a barrier seed layer on the bond pads, sidewalls of the associated dielectric layer, and the nanopillars.

[0073] In one aspect, the technology described herein relates to a polarized imaging device that includes a microlens array having at least two microlenses, a polarization filtering metasurface having two or more polarization filtering ranges, and an imaging sensor having at least two ranges, where imaging light including one or more polarization states is directed by the microlenses onto the polarization filtering metasurface, and the polarization filtering metasurface is configured to direct the one or more polarization states onto the one or more ranges of the imaging sensor.

[0074] In one aspect, the microlens array includes refractive microlenses.

[0075] In one aspect, the microlens array further includes a metasurface configured to provide a refractive microlens effect.

[0076] In one aspect, the microlens array includes a metasurface configured to provide a refractive microlens effect.

[0077] In one aspect, each of the at least two microlenses resides over a single area of ​​the one or more areas of the imaging sensor.

[0078] In one aspect, each of the at least two microlenses is over two or more sensor areas of the one or more areas of the imaging sensor.

[0079] In one aspect, each of the at least two microlenses overlies a single polarization range of one or more of the two or more polarization filtering ranges.

[0080] In one aspect, each of the at least two microlenses overlies two or more of the two or more polarizing filtering areas. [Brief description of the drawings]

[0081] The present specification will be more fully understood with reference to the following figures, which are presented as exemplary embodiments of the present invention and should not be construed as exhaustive of the scope of the present invention.

[0082] [Figure 1] FIG. 1 shows, by way of example, a schematic diagram of a conventional polarization imaging system.

[0083] [Diagram 2] FIG. 2 shows, by way of example, a schematic diagram of a polarization imaging system.

[0084] [Figure 3A] 3A and 3B show schematic diagrams of a Polarization Sorting Metasurface Microlens Array (PSOMMA) according to an embodiment of the present invention. [Figure 3B] 3A and 3B show schematic diagrams of a Polarization Sorting Metasurface Microlens Array (PSOMMA) according to an embodiment of the present invention.

[0085] [Figure 3C-1] FIG. 3C-1 conceptually illustrates the optical path of a single-layer metasurface utilizing a blazed grating approach in accordance with an embodiment of the present invention.

[0086] [Figure 3C-2] FIG. 3C-2 conceptually illustrates the optical path of a PSOMMA and a single-layer metasurface acting as a collimation lens in accordance with an embodiment of the present invention.

[0087] [Figure 3C-3] FIG. 3C-3 conceptually illustrates the optical path of a PSOMMA and a metasurface of two separate layers acting as a collimation lens in accordance with an embodiment of the present invention.

[0088] [Figure 4A] FIG. 4A shows a PSOMMA with two polarizations in each lenslet according to an embodiment of the present invention.

[0089] [Figure 4B] FIG. 4B shows a PSOMMA with two polarizations for each lenslet according to an embodiment of the present invention.

[0090] [Figure 5A-1] FIG. 5A-1 illustrates an optical system incorporating a PSOMMA according to an embodiment of the present invention.

[0091] [Figure 5A-2] 5A-2 and 5A-3 show examples of optical systems incorporating PSOMMAs according to various embodiments of the present invention. [Figure 5A-3] 5A-2 and 5A-3 show examples of optical systems incorporating PSOMMAs according to various embodiments of the present invention.

[0092] [Figure 5B] FIG. 5B illustrates an optical system incorporating a PSOMMA according to an embodiment of the present invention.

[0093] [Figure 5C-1] 5C-1, 5C-2, and 5C-3 show optical systems incorporating PSOMMAs according to various embodiments of the present invention. [Figure 5C-2]5C-1, 5C-2, and 5C-3 show optical systems incorporating PSOMMAs according to various embodiments of the present invention. [Figure 5C-3] 5C-1, 5C-2, and 5C-3 show optical systems incorporating PSOMMAs according to various embodiments of the present invention.

[0094] [Figure 6A] 6A and 6B show exemplary polarization distributions of an image sensor according to an embodiment of the present invention. [Figure 6B] 6A and 6B show exemplary polarization distributions of an image sensor according to an embodiment of the present invention.

[0095] [Figure 7] FIG. 7 illustrates a schematic of an example of the functionality of a polarization imaging system including an MLA integrated with a PSOMMA according to one embodiment of the present invention.

[0096] [Figure 8] 8A and 8B show various offset pixel architectures according to various embodiments of the present invention.

[0097] [Figure 9A] 9A and 9B show various high fidelity pixel architectures according to embodiments of the present invention. [Figure 9B] 9A and 9B show various high fidelity pixel architectures according to embodiments of the present invention.

[0098] [Figure 10A] 10A and 10B show various hybrid intensity / polarization architectures according to embodiments of the present invention. [Figure 10B] 10A and 10B show various hybrid intensity / polarization architectures according to embodiments of the present invention.

[0099] [Figure 11]11A-11C show various hybrid architectures including MLA and PSOMMA according to various embodiments of the present invention.

[0100] [Figure 12-1] 12A-12G illustrate various steps of a direct manufacturing method according to an embodiment of the present invention. [Figure 12-2] 12A-12G illustrate various steps of a direct manufacturing method according to an embodiment of the present invention.

[0101] [Figure 13] 13A-13D show various steps of a wafer bonding method according to an embodiment of the present invention.

[0102] [Figure 14A] FIG. 14A shows a plurality of second wafer dies bonded to an image sensor wafer according to an embodiment of the present invention.

[0103] [Figure 14B] FIG. 14B illustrates image sensor die 1404 after image sensor wafer 1302 has been singulated according to an embodiment of the invention.

[0104] [Figure 15] FIG. 15 illustrates, by way of example, a PSOMMA sensor 1500 fabricated in accordance with an embodiment of the present invention.

[0105] [Figure 16] 16A-16C illustrate, by way of example, a method for fabricating a CIS wafer 1502 according to an embodiment of the present invention.

[0106] [Figure 17] FIG. 17 shows a top view of a CIS wafer 1602 according to an embodiment of the present invention.

[0107] [Figure 18-1]18A-18C illustrate, by way of example, a method for fabricating a nanopillar wafer according to an embodiment of the present invention. [Figure 18-2] 18A-18C illustrate, by way of example, a method for fabricating a nanopillar wafer according to an embodiment of the present invention.

[0108] [Figure 19] FIG. 19 shows a plan view of a nanopillar substrate according to an embodiment of the present invention.

[0109] [Figure 20] 20A and 20B illustrate, by way of example, a method for fabricating a PSOMMA sensor according to an embodiment of the present invention.

[0110] [Figure 21] 21A and 21B show a process flow for manufacturing a CIS wafer according to an embodiment of the present invention.

[0111] [Figure 22] 22A and 22B show a process flow for fabricating a nanopillar wafer according to an embodiment of the invention.

[0112] [Figure 23-1] Figures 23A-23H show a manufacturing process for producing an imaging sensor using a CIS wafer manufactured using the process described in Figures 21A and 21B according to an embodiment of the present invention, and a nanopillar wafer manufactured using the process described in Figures 22A and 22B. [Figure 23-2] Figures 23A-23H show a manufacturing process for producing an imaging sensor using a CIS wafer manufactured using the process described in Figures 21A and 21B according to an embodiment of the present invention, and a nanopillar wafer manufactured using the process described in Figures 22A and 22B. [Figure 23-3]Figures 23A-23H show a manufacturing process for producing an imaging sensor using a CIS wafer manufactured using the process described in Figures 21A and 21B according to an embodiment of the present invention, and a nanopillar wafer manufactured using the process described in Figures 22A and 22B. [Figure 23-4] Figures 23A-23H show a manufacturing process for producing an imaging sensor using a CIS wafer manufactured using the process described in Figures 21A and 21B according to an embodiment of the present invention, and a nanopillar wafer manufactured using the process described in Figures 22A and 22B.

[0113] [Figure 24] Figures 24A-24C show a manufacturing process for producing an imaging sensor using a CIS wafer manufactured using the process described in Figures 21A and 21B according to an embodiment of the present invention, and a nanopillar wafer manufactured using the process described in Figures 22A and 22B.

[0114] [Figure 25-1] 25A to 25H show a manufacturing process for manufacturing an imaging sensor according to an embodiment of the present invention. [Figure 25-2] 25A to 25H show a manufacturing process for manufacturing an imaging sensor according to an embodiment of the present invention. [Figure 25-3] 25A to 25H show a manufacturing process for manufacturing an imaging sensor according to an embodiment of the present invention.

[0115] [Figure 26] FIG. 26 illustrates, by way of example, the operation of a metasurface microlens array (MLA) according to an embodiment of the present invention.

[0116] [Figure 27A] FIG. 27A shows an example pixel arrangement of a four-polarization pixel according to an embodiment of the present invention.

[0117] [Figure 27B]FIG. 27B shows an example pixel arrangement of a dual polarization pixel according to an embodiment of the present invention.

[0118] [Figure 27C] FIG. 27C shows an example pixel arrangement of a four-polarization pixel according to an embodiment of the present invention.

[0119] [Figure 28A] FIG. 28A is a cross-sectional view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0120] [Figure 28B] FIG. 28B is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0121] [Figure 28C] FIG. 28C is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0122] [Figure 29A] FIG. 29A is a cross-sectional view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0123] [Figure 29B] FIG. 29B is a top view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0124] [Figure 29C] FIG. 29C is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0125] [Figure 30A] FIG. 30A shows a cross-sectional view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0126] [Figure 30B] FIG. 30B shows a top view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0127] [Figure 30C] FIG. 30C is a top view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention.

[0128] [Figure 31A] FIG. 31A shows a cross-sectional view of an imaging device including polarization filtering capabilities according to an embodiment of the present invention.

[0129] [Figure 31B] FIG. 31B shows a top view of an imaging device including polarization filtering capabilities according to an embodiment of the present invention.

[0130] [Figure 32A] FIG. 32A shows a cross-sectional view of an imaging device including polarization filtering capabilities according to an embodiment of the present invention.

[0131] [Figure 32B] FIG. 32B shows a cross-sectional view of an imaging device including polarization sorting capabilities according to an embodiment of the present invention.

[0132] [Figure 32C] FIG. 32C shows a cross-sectional view of an imaging device including polarization sorting capabilities according to an embodiment of the present invention.

[0133] [Figure 33A] FIG. 33A illustrates, by way of example, a plan view of a polarization filtering nanograting according to an embodiment of the present invention.

[0134] [Figure 33B] FIG. 33B shows an exemplary plan view of a polarization sorting metasurface in accordance with an embodiment of the present invention.

[0135] [Figure 34A] FIG. 34A shows an example schematic plan view of a linear polarization sorting metasurface in accordance with an embodiment of the present invention.

[0136] [Figure 34B] FIG. 34B shows an exemplary schematic plan view of a circular polarization sorting metasurface in accordance with an embodiment of the present invention.

[0137] [Figure 34C] FIG. 34C shows a schematic top view of an arbitrary polarization sorting metasurface according to an embodiment of the present invention.

[0138] [Figure 35A] FIG. 35A shows a sparsely distributed PSOMMA sensor according to an embodiment of the present invention.

[0139] [Figure 35B] FIG. 35B shows a cross-sectional view of a sparsely distributed PSOMMA sensor according to an embodiment of the present invention.

[0140] [Figure 36A] FIG. 36A illustrates, by way of example, a PSOMMA sensor according to an embodiment of the present invention.

[0141] [Figure 36B] FIG. 36B illustrates, by way of example, a PSOMMA sensor according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0142] Disclosed herein is an optical device that includes individual lenslets that classify polarization so that the polarization information of the resulting scene can be reconstructed. Specifically, the invention described herein includes an optical device that includes a metasurface microlens array that includes lenslets, which can be coupled to an image sensor. The phase and polarization split at each lenslet can be uniquely specified. Each lenslet can split the incoming light into at least two polarizations that are directed to a specific pixel under the imaging sensor. Independent of the polarization control at each lenslet, the phase of each lenslet can also be uniquely specified. The phase response of each lenslet can be customized so that it corresponds to a certain angle of incidence on that lenslet. In some embodiments, the polarization sorting metasurface microlens array can be customized for a certain optical system and directly integrated into the image sensor. In some embodiments, the image sensor may include a complementary metal oxide semiconductor (CMOS) image sensor, a charge-coupled device sensor, a silicon diode, a cadmium sulfide sensor diode, an RGB sensor, an indirect time-of-flight (iToF) sensor, a direct time-of-flight (dToF) sensor, and / or various other types of sensors.

[0143] Polarization sorting metasurfaces can include repeating structures of supercells or superpixels and / or non-polar open spaces between them to create a sparsity effect.

[0144] Most conventional polarization imaging systems work by absorbing certain polarization states while allowing the unabsorbed states to pass through a photosensitive sensor. By knowing which polarization states are absorbed and which are passed, a polarization image of the scene can be constructed. However, such designs can be inefficient because the absorbed light is dissipated as heat rather than being transferred and sensed in a way that could provide useful polarization information. This design can have poor efficiency or signal-to-noise ratio. This configuration still preserves the polarization information, but because light is absorbed, efficiency is compromised. Furthermore, common techniques for performing this type of polarization measurement (e.g., wire grid polarizers) can only select linear polarization states, so elliptical polarization states may not be accessible.

[0145] FIG. 1 shows a schematic diagram of a conventional polarization imaging system as an example. As shown, the incident light 106 may include multiple polarizations, such as S-polarized light and P-polarized light. The incident light passes through a polarizer 102, which may pass only one polarization. If the incident light 106 includes S-polarized light and P-polarized light, the polarizer 102 may pass only S-polarized light 106a and absorb P-polarized light. The amount of S-polarized light 106a may be measured by a photosensitive sensor 104, which may provide data regarding the amount of S-polarized light 106a. Unfortunately, the P-polarized light is absorbed by the polarizer 102, which may be an unwanted by-product, such as heat or scattered light from reflection.

[0146] An embodiment of the present invention relates to a metasurface polarization imaging system, which, in contrast to conventional polarizers, spatially separates polarized light by sending each of the designed polarizations to a specific diffraction angle. Examples of metasurface optical elements, including shapes and orientations that deflect light in a direction that depends on the polarization of the light, are disclosed in U.S. Patent Application Publication No. 2021 / 0286188, filed February 22, 2019, entitled "ARBITRARY POLARIZATION-SWITCHING METASURFACES," which is incorporated herein by reference in its entirety for all purposes. Examples of gratings configured to perform parallel polarization analysis of multiple polarization orders of incident light of arbitrary polarization are also disclosed in International Patent Application Publication No. 2020214615, filed April 14, 2020, entitled "SYSTEMS AND METHODS FOR ANALYZING PARALLEL POLARIZED BEAM," which is incorporated herein by reference in its entirety for all purposes. Additionally, examples of polarizers including metasurface elements that provide different responses based on the polarization of the incident light are disclosed in U.S. Patent Application Publication No. 2021 / 0048569, entitled "Polarization State Generation with Metasurfaces," filed July 22, 2020, and incorporated by reference in its entirety for all purposes. All of the designs in these references may be incorporated into the present disclosure to split incident light into different polarizations that are directed in different directions.

[0147] In such systems, the efficiency can be as much as two times higher than conventional polarization gratings, since light of different polarizations is diffracted in different directions and detected by different image sensors, rather than being absorbed. However, for these systems, the metasurface element splits the aperture of the imaging system, resulting in the formation of images with specific polarizations in separate areas of the image sensor. For example, if the metasurface is designed to split the incident light into four polarization states, the metasurface imaging system can form four separate images of a single object, with each of the four images formed in a separate spatial domain (e.g., quadrant) of the image sensor, and a specific polarization state associated with each image. FIG. 2 shows, by way of example, a schematic diagram of a polarization imaging system. The polarization imaging system includes a metasurface element 202 that splits the incident light 206 into different polarizations. As shown, the incident light 206 can include a single mixed polarization state. The incident light 206 can be completely unpolarized, or it can be a single pure polarization state or some mixed state. The incident light 206 may contain four polarizations: Pol1, Pol2, Pol3, and Pol4. In more mathematical terms, the incident light is represented by a Stokes vector S. Each output diffraction direction is represented by a different Stokes vector M, which corresponds to a row of the Mueller matrix. i Each output direction is associated with the Mueller matrix U i When light is captured by an image sensor, the total intensity of the light can be measured. The Mueller matrix U multiplied by the incident Stokes vector S i is the output Stokes vector in each direction O i Give O i =U i *S. When light is captured by the image sensor, the Stokes vector O i The first entry of corresponds to the light intensity. There are four indices: 0, 1, 2, and 3, so this is O i [0]=(U i *S)[0], where [x] represents the x-th element of the vector, starting from 0. This corresponds to the Mueller matrix U i Take the first row of the Stokes vector S((U i*S)[0]=sum j (U {i,(0,j)} *S j )) is equivalent to calculating the dot product of this Mueller matrix U i The first line of also follows the same algebra as the Stokes vectors, so the Stokes vector M i The intensity in each output diffraction direction can be considered as M i and S. The diffraction orders may not necessarily be of the same polarization state that is selected.

[0148] The metasurface element 202 may split the incident light 206 into diffracted light 206a, with each of the four polarizations being directed in a different direction. The diffracted light 206a in each direction has an intensity that is proportional to the projection of that particular light polarization state onto the incident state. The diffracted light 206a may enter a set of four different image sensors 204. In an embodiment, the diffracted light 206a may enter four different ranges of a single image sensor, two ranges of two image sensors, or other combinations of ranges and sensors. Although the image sensors 204 and the diffracted light 206a are shown in different horizontal positions, this is merely exemplary and the image sensor 204 may in fact be in different quadrants, with the diffracted light 206a sending each polarization into a different quadrant.

[0149] The incident light 206 can be of any polarization state. The metasurface element can split the incident light into diffracted light, with each of the four directions corresponding to a different target polarization state, and the intensity of that direction is determined by the overlap of the incident polarization state with the target polarization state.

[0150] The metasurface element 202 overcomes the absorption losses and / or complexity of conventional polarization imaging systems, including the polarizer 102 described in connection with FIG. 1, but in some embodiments may benefit from a specific field of view aperture or illumination source to prevent overlapping sub-images at the image sensor 204.

[0151] Various embodiments of the present invention utilize a polarization sorting metasurface microlens array (PSOMMA) to spatially mix polarization states across an image sensor. In some embodiments, the PSOMMA may be the last element before the image sensor, and each lenslet including the PSOMMA may direct a set of designed polarization states to an individual subpixel, or imaging portion, or sensor area. Furthermore, it may not be necessary to use the illumination source's field of view or additional apertures to prevent sub-images from overlapping at the image sensor. Finally, the image sensor and the PSOMMA may be incorporated into any existing optical imaging system that may include refractive optical elements as shown in and described in conjunction with FIGS. 5A-1 to 5-3.

[0152] 3A and 3B show schematic diagrams of PSOMMA according to an embodiment of the present invention. In FIG. 3A, PSOMMA includes individual metasurface lenslets 302. The number of individual lenslets depends on the optical system, but can be any number in general. Each lenslet can split the incident light into individual polarizations for each diffraction angle. Each lenslet can split the light into at least two polarizations, but can generally split into any number of polarizations. As shown, the first lenslet L1 can split the incident light into four different polarizations 304: pol1, pol2, pol3, and pol4. Additionally, the second lenslet L2 can split the incident light into four different polarizations 306: pol5, pol6, pol7, pol8. The light can be split in four different directions in each direction proportional to the selected polarization state for that direction. Similarly, the nth lenslet Ln can split the incident light into four different polarizations 308: poln, poln+1, poln+2, and poln+3. As shown here, a particular polarization state may be unique for each lenslet (denoted as pol1, pol2, poln), although the same two or more polarization states may be utilized in each lenslet. For example, a first lenslet L1 and a second lenslet L2 may split the incoming light into the same four different polarizations: pol1, pol2, pol3, pol4. Additionally, the phase function of each lenslet may be uniquely specified.

[0153] As shown in FIG. 3B, PSOMMA can be coupled to an image sensor 308 having any number of pixels (denoted p1, p2, p3, pn). Each pixel can be a number of image sensing units. In such a case, the job of PSOMMA can be to diffract each polarization state into a specific pixel. The full polarization state of the scene can be reconstructed on a pixel-by-pixel basis by designing the polarization state to which the pixel readout corresponds. Although the drawings here are shown in one dimension, it is understood that the same principles apply to two-dimensional lenslet and pixel arrays. Although the incident light shown has a chief ray angle (CRA) of 0 degrees, the CRA of the incident light can be any angle or even vary across the lens. Thus, the incident light can be collimated but can also be incident on the metasurface lenslet at other angles. In some embodiments, metasurfaces are used to provide microlens array functionality, and the metasurfaces can be designed such that the lenslets are optimized to accommodate different entrance angles (e.g., non-zero CRA) across the image sensor field, minimizing effects that would otherwise occur for lenses designed for zero CRA functionality. In some embodiments, physical microlens shifting can be provided, which is a technique for matching the CRA of the image sensor with the microlenses. In this technique, the periodicity of the microlens array is reduced across the sensor, allowing the CRA of the microlenses to be partially cancelled.

[0154] In some embodiments, the microlens array may provide a microlens function (e.g., focusing light at an image sensor) using metasurfaces in a manner that provides a microlens shift similar to a physical microlens shift. The metasurfaces may be locally designed in a way that they can match both the azimuth and elevation angles of the primary refractive lens, resulting in CRA matching across the sensor or at different incident imaging light angles. This is complicated for traditional physical microlenses, but can be achieved by leveraging metasurfaces with microlens functions. In some embodiments, the metasurfaces may be utilized to provide a collimation function that allows light received from the primary refractive lens or entrance pupil to be collimated and / or directed to the center of the sensor range.

[0155] 3C-1 conceptually illustrates the optical path for a single-layer metasurface utilizing a blazed grating approach in accordance with an embodiment of the present invention. Based on the generalized Snell's law, the relationship between the phase gradient, the transmission azimuth angle, and the elevation angle can be written as follows:

number

[0156] The phase function of the interface in the case of PSOMMA with CRA matching includes the blazed grating for CRA matching and the phase function of PSOMMA. As a result, equation (1) can be rewritten as follows:

number

[0157] To simplify the problem, when the CRA matching is perfectly satisfied and θt = φt = 0°, the phase of the blazed grating, without any PSOMMA function, can be defined as:

number

[0158] The actual phase function of the blazed grating in equation (3) can be calculated as follows:

number

[0159] If the metasurface locally satisfies equation (5), it can completely cancel the refractive lens CRA and direct it back to the target sensor pixel.

number

[0160] FIG. 3C-2 conceptually illustrates the optical path for a PSOMMA and a single-layer metasurface acting as a collimation lens according to an embodiment of the present invention. A representation of a 2D scenario is shown in which the metasurface is placed along the y-axis. Equation (6) shows the trigonometric functions that can be utilized to calculate the equivalent effective focal length (EFL) for the collimation function.

number

[0161] This can be simplified to calculate the collimation phase using the target EFL as follows:

number

number

[0162] y' センサ can be one-quarter of the physical dimension of the sensor. This is an approximation instead of optimizing the collimation phase over all CRAs received by the metasurface. Another estimate of the EFL can be:

number

[0163] FIG. 3C-3 conceptually illustrates the optical path of two separate layers of metasurfaces acting as PSOMMA and collimation lenses according to an embodiment of the present invention. One metasurface (MS) layer acts as a collimation lens and one MS layer acts as PSOMMA.

[0164] FIG. 4A illustrates a PSOMMA with two polarizations for each lenslet according to an embodiment of the present invention. The PSOMMA includes multiple lenslets 402 (L1, L2, LN, LN+1), each of which can split the incoming light into two polarizations (pol). As shown, an example includes L1, which can split the incoming light into pol1 in one direction and pol2 in another direction. L2 can also split the incoming light into pol3 and pol4. Each lenslet can be exactly over two pixels. For example, as shown, L1 can be over pixels p1 and p2, directing light for pol1 to p1 and light for pol2 to p2. In an embodiment, the polarizations for the two lenslet sets can be repeated across the image sensor 404. For example, L1 splits the light into pol1 and pol2, L2 splits the light into pol3 and pol4, and the pattern may be repeated over the entire image sensor 404, or over a portion or portions of the image sensor 404, such that LN splits the light into pol1 and pol2, and LN+1 splits the light into pol3 and pol4. In some embodiments, the polarization is split into only two states across the image sensor 404. For example, in the PSOMMA described in connection with FIG. 4A, pol1 is equivalent to pol3, and pol2 is equivalent to pol4. Thus, both L1 and L2 may split the light into the same polarization, pol1 and pol2. Finally, it is understood that the polarization state of each lenslet may be completely unique and independent, and is not limited to a linear polarization state. For example, pol1 may be right-handed circularly polarized and pol2 may be left-handed circularly polarized. Furthermore, pol1 may be S-polarized while pol2 may be P-polarized.

[0165] FIG. 4B illustrates a PSOMMA with two polarizations for each lenslet according to an embodiment of the present invention. This configuration is similar to that described in connection with FIG. 4A. However, in this configuration, the PSOMMA 406 includes a first lenslet L1 that directs a first polarization pol1 to a first imaging portion p1 of the image sensor 408 and a second polarization pol2 to a second imaging portion p2 of the image sensor 408. Similarly, the PSOMMA 406 includes a second lenslet L2 that directs a first polarization pol1 to a first imaging portion p1 and a second polarization pol2 to a second imaging portion p2. Thus, the same imaging portions p1, p2 may be shared by the first lenslet L1 and the second lenslet L2.

[0166] FIG. 5A-1 illustrates an optical system incorporating PSOMMA according to an embodiment of the present invention. As shown, PSOMMA 502 can be combined with one or more refractive lenses 504 in an optical system to provide a complete polarization imaging system. PSOMMA 502 can be the last element of the imaging system before the image sensor 506. In an embodiment, each lenslet of PSOMMA 502 can be customized for a certain polarization response. In an embodiment, each lenslet of PSOMMA 502 can be customized for a certain unique phase function. The unique phase function can be used to improve the performance of PSOMMA 502 to change the chief ray angle of the optical system. In an embodiment, each lenslet of PSOMMA 502 can be customized for both a certain unique phase function and a certain polarization response. There can be a distance offset between the image sensor 506 and PSOMMA 502. The material between the image sensor 506 and PSOMMA 502 at the offset distance can be air or a solid material such as glass, quartz, SiO2, Si3N4, or a polymer. Many optical imaging systems have a microlens array (MLA) in front of the image sensor to combine light into individual pixels. In such systems, the microlens array may not be able to distinguish polarizations and may not provide any unique phase function for each pixel. The PSOMMA 502, as previously mentioned, may diffract different polarizations in the incident light into different directions and provide a certain unique phase function for the different polarizations of the incident light.

[0167] In an embodiment, the PSOMMA 502 may be positioned to re-image an image plane from an optical system. The one or more refractive lenses 504 in FIG. 5A-1 are merely illustrative. FIGS. 5A-2 and 5A-3 show examples of optical systems incorporating PSOMMA according to various embodiments of the present invention. In FIG. 5A-2, the 0P trace is provided with several different fields of view, but with a central central ray diffracting through the PSOMMA 502 and into the image sensor 506. In FIG. 5A-3, the 0F trace is provided with a normal field of view, with several rays traced across the pupil, and several rays diffracting through the PSOMMA 502 and into the image sensor 506.

[0168] FIG. 5B illustrates an optical system incorporating a PSOMMA according to an embodiment of the present invention. As illustrated, a light source 508 may output optical light toward a PSOMMA 502a. Although the light from the light source 508 is shown as collimated, the light may have different angles of incidence and may not be perfectly collimated. The PSOMMA 502a may include all of the functions of the PSOMMA 502 described in connection with FIG. 5A. However, the PSOMMA 502 may also have at least some of the functions of the one or more refractive lenses 504 described in connection with FIG. 5A or may include microlens array functions. Although the one or more refractive lenses 504 are not illustrated as being present in FIG. 5B, a portion of the one or more refractive lenses 504 may be present to perform some of the functions of the one or more refractive lenses 504, while the PSOMMA 502a may be incorporated to perform the remaining functions. The PSOMMA 502a may be the last element of the imaging system before the image sensor 506.

[0169] The light source can be a fixed near-infrared light source, a Vertical-Cavity Surface Emitting Laser (VCSEL), an LED, an Edge-Emitting Laser (EEL), sunlight, and / or other ambient lighting. In some embodiments, the light source can be designed to have a specific fixed polarization across the illumination field, or a point-by-point polarization pattern across the illumination field. For example, the illumination pattern projected onto the scene can have a fixed circular polarization, e.g., left or right circular polarization. In some embodiments, it can be a fixed linearly polarized or elliptically polarized illumination. In some cases, two different fixed polarizations can be used simultaneously or sequentially. Figures 5C-1, 5C-2, and 5C-3 show optical systems incorporating PSOMMA according to various embodiments of the present invention. The optical system includes a primary lens 552 that refracts light toward the PSOMMA 554. The PSOMMA 554 distributes the refracted light from the primary lens 552 to an image sensor 556. In FIG. 5C-1, a primary lens image plane 558a of the primary lens 552 overlaps the PSOMMA 554 such that the primary lens 552 is focused on the PSOMMA 554.

[0170] In FIG. 5C-2, primary lens image plane 558b of primary lens 552 is behind PSOMMA 554 and image sensor 556, thereby focusing PSOMMA 554 at the image plane. In FIG. 5C-3, primary lens image plane 558c of primary lens 552 is between primary lens 552 and PSOMMA 554. Thus, in FIG. 5C-2, image plane 558b of primary lens 552 is behind image sensor 556, while in FIG. 5C-3, image plane 558c is in front of image sensor 556. The arrangement of FIG. 5C-3 provides increased flexibility in physical configuration.

[0171] In some embodiments, the primary lens 552 is a biconvex lens. In some embodiments, the primary lens 552 can be a plano-convex lens. In some embodiments, the primary lens 552 can be a multi-refractive lens configuration. In some embodiments, the PSOMMA 554 can be replaced with a combination of a polarization-dependent metasurface next to a microlens array. The microlens array can be a biconvex lens array or a plano-convex lens array. Any of the configurations disclosed in Figures 5C-1 to 5C-3 can be utilized and they can provide different benefits such as higher spatial resolution, larger viewing angle, better directional sampling accuracy, etc.

[0172] 6A and 6B show the polarization distribution of an exemplary image sensor according to an embodiment of the present invention. FIG. 6A is a top view of an exemplary polarization state at each pixel of the image sensor after the light passes through PSOMMA. As shown, each lenslet 604 may divide the intensity of the incident light proportionally to the polarization content of four distinct states: right elliptical 602a, vertical 602b, diagonal 602c, and left circular 602d. These four pixels with unique states form a superpixel of the imaging system and may be repeated N times across the image sensor. Although four repeating polarization states are shown, PSOMMA may be used to specify a unique polarization state at each of the pixels on the image sensor, which may be two, three, or more unique polarization states that repeat. Advantageously, the light is not filtered (e.g., absorbed) before reaching the image sensor, and PSOMMA is not limited to only linear polarization states. FIG. 6B shows a fully polarized superpixel, with the positions of the individual lenslets 604 shown in bold lines. Each lenslet 604 may separate the incoming light into four sub-pixels, each of which has a different polarization state.

[0173] The image sensor may be a CMOS sensor, a time-of-flight (ToF) sensor, an indirect time-of-flight (iToF) sensor, and / or an RGB sensor. The readout timing and method of the image sensor, and the frame rate, may include binning. For example, in a 2x2 pixel configuration, readout without polarization and then readout with polarization to provide efficient information capture. In other words, from a signal capture and processing perspective, polarized pixels are binned together. Different pixels may be sampled at different times or more or less frequently for imaging or energy purposes. For an iToF sensor, most pixels may be of CMOS type and some small percentage may be iToF pixels (e.g. 10% or 20%); iToF may be in 2D mode without polarization. Some configurations may also have a sparse idea in the sensor (such as 2D mode where only some pixels are in 3D mode), which may save energy.

[0174] In some embodiments, diffractive optical elements (DOEs) can be used on some of the splitting sides, for example, conventional DOEs can be applied instead of metasurfaces for some of the PSOMMA lenslets.

[0175] (Example of a polarized imaging system including a microlens array) In an embodiment, the polarization imaging system may include two separate components: a refractive microlens array (MLA) and a PSOMMA. The MLA may tile the projected image. FIG. 7 shows a schematic example of the functionality of a polarization imaging system including an MLA integrated with a PSOMMA according to an embodiment of the present invention. The polarization imaging system may include a separate refractive MLA 704 and a PSOMMA 702. The PSOMMA 702 may be a polarization metalattice. In an embodiment, the refractive MLA 704 may be implemented in the same layer as the PSOMMA 702. In an embodiment, the MLA 704 may be implemented as a separate planar layer from the PSOMMA 702, as shown. In an embodiment, the MLA 704 is a conventional refractive MLA, and thus the polarization imaging system may include a conventional refractive MLA and a PSOMMA 702. In an embodiment, the MLA 704 is integrated with the PSOMMA 702, whereby a metasurface may be used to produce both a layer including an MLA and a layer including a PSOMMA on a single substrate. The layer including the MLA 704 may include a metasurface element.

[0176] The MLA 704 may be adjusted relative to the image plane of the imaging system so that it reduces the incoming light by a factor of 2 or more so that when tiled, the separated images do not overlap. An example of tiling is shown in FIG. 6B. Although it may be desirable to have the PSOMMA 702 as close as possible to the MLA 704, an embodiment may include combining the MLA 704 and PSOMMA 702 in a single layer. The pixels are shown diagrammatically as adjacent boxes. The active area of ​​the pixel may be smaller than that shown diagrammatically here, and the magnification may be greater than 2 to illuminate only the active area.

[0177] The MLA 704 includes a focal length. A distance 708 from a primary image plane 707 may be greater than twice the focal length of the MLA 704. Imaging to pixels of a range 716 in the primary image plane 707 may overlap each microlens of the MLA 704. The PSOMMA 702 outputs light into an image sensor 710 that includes a pixel grid. A distance 712 from the PSOMMA 702 to the image sensor 710 may be less than the focal length of the MLA 704. A ray trace 714a including the chief ray (solid line) and marginal ray (dotted line) is shown generally at 0F. A ray trace 714b including the chief ray (solid line) and marginal ray (dotted line) is shown generally at 1F.

[0178] 8A and 8B show various offset pixel architectures according to various embodiments of the present invention. Instead of targeting the diffraction orders such that the diffraction is symmetric around the non-diffraction image, the non-diffraction image can be selected as one of the diffraction orders (e.g., the zeroth order). These architectures share many similarly numbered features with the architecture of FIG. 7, and the description is applicable in these architectures. The description will not be repeated in detail.

[0179] As shown in FIG. 8A, the center of each lenslet of the microlens array may be aligned directly over the zero-order light between the pol1 and pol2 lights. The zero-order light may have a detrimental effect on the fidelity of the reconstructed polarization. Therefore, it may be advantageous to have the zero-order light pass through the center of the photosensor between the pol1 and pol2 lights. The active area of ​​a pixel (the photosensitive area that generates electronic charge by the incident light) may be smaller than the value of the microlens pitch divided by the number of pixels it is divided into. The zero-order light from the PSOMMA may not even be incident on the active area of ​​a pixel because the active area of ​​the pixel array under the photosensor may be offset from where the zero-order light is incident. The zero-order light may occur simultaneously with the diffracted light. Because the zero-order light is "uncontrolled", it does not effectively analyze the incident polarization and does not carry a polarization signal. Therefore, the zero-order light may be considered noise. Therefore, by directing it to a non-photosensitive area, the noise can be reduced.

[0180] In an embodiment, the zero order light may be at least partially dispersed between the pol1 and pol2 lights. When the active area of ​​the image sensor overlaps with the zero order light, a portion of the zero order light may be shared as noise between the pixels of the image sensor.

[0181] In some cases, it may be difficult to align the zero-order light with the non-active areas of the pixel array of the image sensor. In this case, it may be better for the zero-order light to be diffracted in the same direction as one of the polarizations of the light. FIG. 8B shows an offset pixel architecture, where the zero-order light is diffracted in the same direction as the pol1 light, but beside the pol2 light. The target pixel may be offset with respect to the center of the lens. Only one of the pixels will experience noise from the zero-order, which may facilitate subsequent polarization recovery. The zero-order image is shown offset in the vertical axis. Mathematically, the lenslet in FIG. 8A may shorten all analyzer Stokes vectors on the Poincaré sphere, reducing the degree of polarization of the pol1 and pol2 lights. On the other hand, in the lenslet in FIG. 8B, only the vector containing the pol1 light and the zero-order light is shortened, and the pol2 light is not shortened.

[0182] 9A and 9B show various high fidelity pixel architectures according to embodiments of the present invention. These architectures share many similar features with the architectures of FIG. 7 and FIG. 8, and the description may be applied to these architectures. The description will not be repeated in detail. As shown in FIG. 9A, the zeroth order light is not diffracted and therefore may pass through the center of the microlens (such as a lenslet). The undiffracted zeroth order light may be imaged to a separate pixel of the image sensor where the diffraction orders are not directed. In this case, none of the Stokes vectors of the analyzer may be shortened and the degree of polarization may not be reduced. The zeroth order light may not affect the fidelity of the reconstructed polarization image. Furthermore, the zeroth order light may be an additional signal for the reconstructed intensity image, rather than noise for the reconstructed polarization. The zeroth order light may not have a preferred polarization and only provide intensity information. In this configuration, it is not necessary to minimize the amount of light that enters the zeroth order, and it can be optimized by design to increase the overall optical efficiency. This configuration is beneficial in applications where tradeoffs can be made between efficiency, signal-to-noise ratio (SNR), and angular resolution. 9B shows various top views of a sensor for an exemplary superpixel implementation with a separate zeroth order pixel combined with a pixel offset. The pixel offset refers to the spatial translation of the underlying pixel array with the microlens array. In one embodiment, pol3 is equal to pol1 and pol4 is equal to pol2. The illustrated combinations are not limiting and other combinations of subpixel positioning are possible.

[0183] 10A and 10B show various hybrid intensity / polarization architectures according to embodiments of the present invention. These architectures share many similar features with the architecture of FIG. 7, and the description may also be applied to these architectures. The description will not be repeated in detail. In these architectures, PSOMMA 706 may not be applied to all lenslets of MLA 704, such that some of the pixels may be imaged directly by the lenslets without PSOMMA 706, and another part of the pixels may be imaged by the lenslets of MLA 704 and PSOMMA 706. This may be achieved by patterning a transparent window 1002 in PSOMMA 706, selectively patterning the back surface of MLA 704 with PSOMMA 706, or other methods suitable for constructing various hybrid MLA polarization metalattices. The offset pixel and high fidelity architectures described above may be further applied to the part of the pixel that includes PSOMMA 706. This hybrid configuration may be beneficial for balancing the tradeoffs between resolution, optical efficiency, polarization fidelity, and size of the image sensor. This involves implementing an extrapolation between pixels receiving undiffracted light and pixels receiving diffracted light from PSOMMA 706.

[0184] FIG. 10A illustrates a hybrid intensity / polarization architecture, where poln (e.g., pol1, pol2, pol3, pol4) are the polarization states of the diffracted light from PSOMMA 706, and In (e.g., l1, l2, l3) are the light that does not pass through PSOMMA 706. The lenslets of MLA 704 are labeled M1, M2, ~Mn. As shown, Poln can be at least two different polarizations. The light that does not pass through PSOMMA 706 can be used to measure intensity, time of flight (ToF), range to target, depth, depth of focus, defocus, and / or color, and the polarization separated light diffracted by PSOMMA 706 can be used to measure various degrees of polarization. FIG. 10B illustrates various exemplary hybrid intensity / polarization subpixel configurations. The solid lines indicate pixels, and each square indicates a subpixel. Poln can include two or more different polarizations, 0 is the undiffracted zero order pixel exiting PSOMMA 706, and In is the light that does not pass through PSOMMA 706. Advantageously, capturing the light intensity can increase the image intensity resolution without increasing the size of the sensor. The captured intensity can also be used as a reference intensity in an interpolation scheme to read out the resolution for the intensity image and manage the noise coming from the zero order light. The resolution of the polarization image can be reduced if some sub-pixels are dedicated to capturing the image intensity.

[0185] 11A-11C show various hybrid architectures including an MLA and a PSOMMA according to various embodiments of the present invention. In FIG. 11A, a substrate 1102 includes a PSOMMA 1104 positioned above an MLA 1106. The MLA 1106 is positioned directly above an image sensor 1108 with an air gap. The PSOMMA 1104 may be embedded within the substrate 1102 in a layer directly above the MLA 1106. A primary image surface 1110 may be within the substrate 1102. In an embodiment, different microlenses of the MLA 1106 may have different sagitta (SAG) and different focal lengths or aspheric appearances. In an embodiment, the MLA 1106 may be implemented as a metasurface, and the metasurface may be used to customize various properties of the MLA 1106. In one embodiment, a metasurface lens can be used to customize an aspheric lens on top of the MLA 1106 or to reduce aberrations from the MLA 1106.

[0186] In some embodiments, the MLA 1106 may include a variable focus with different focal points across the image. The MLA 1106 may include a phase detection autofocus function where a portion of the pupil is obscured. The MLA 1106 may have a low-density format open window depth-of-defocus, or other autofocus that isolates different focal points for the autofocus calculation, for example using different MLA lenslets for each color.

[0187] In FIG. 11B, the MLA 1106 and PSOMMA 1104 are integrated with the substrate 1102, with the MLA 1106 positioned on the surface opposite the image sensor 1108. The primary image plane 1110 may be located above the substrate 1102. The MLA 1106 integrated with the image sensor 1108 functions by directing light from the primary image plane 1110 to the underlying image sensor 1108. The primary image plane 1110 may be formed by optical components such as an optical system lens. In one configuration, the MLA 1106 acquires the primary image plane 1110 and reduces it such that the primary object is imaged to the active area of ​​the pixel in the image sensor 1108. The primary image plane 1110 may be an image plane formed by the optical system. The primary image plane 1110 may be distinct from an image plane formed by the MLA 1106 in the image sensor.

[0188] The hybrid architecture of FIG. 11C is similar to FIG. 11B, but MLA 1106a may be a planar MLA layer that may play the same optical role as the MLA layer. This planar MLA layer may be an MLA that includes a metasurface. Further examples of polarization imaging systems that include an MLA are discussed in connection with FIGS. 28A-28C, 29A-29C, 30A-30C, 31A-31B, and 32A-32C.

[0189] (Example method of PSOMMA fabrication and integration with an image sensor) Various methods for the fabrication of PSOMMA integrated with an image sensor are considered with three specific methods described below.

[0190] The first method is direct fabrication of PSOMMA on top of the image sensor. Figures 12A-12G show various steps of a direct fabrication method according to an embodiment of the present invention. In Figure 12A, an image sensor wafer 1202 is provided having a planarized or mostly planarized surface. The image sensor wafer 1202 may include an image sensor. In Figure 12B, a spacer layer 1204 is deposited on the planarized surface of the image sensor wafer 1202. The thickness of the spacer layer 1204 may determine the distance between the PSOMMA and the image sensor. The spacer layer 1204 may include a dielectric material (e.g., SiO2, Si3N4), a polymer layer, or other suitable layer that preferably has a refractive index of less than 1.6 at the operating wavelength of the image sensor. In Figure 12C, one or more additional layers 1206 are deposited on top of the spacer layer 1204. In FIG. 12D, one or more additional layers 1206 are patterned and / or etched to form nanoscale pillars 1206a. Examples of nanoscale pillars are described in U.S. Patent Application Publication No. 2018 / 0341090, entitled "Atomic Layer Deposition Process for Fabricating Dielectric Metasurfaces for Wavelengths in the Visible Spectrum," filed May 22, 2018, and incorporated by reference in its entirety for all purposes. The patterning and / or etching may be performed using a photolithography process. The patterning and / or etching may include a wet etching process or a dry etching process. The nanoscale pillars 1206a may be metasurface pillars. In FIG. 12E, the nanoscale pillars 1206a may be encapsulated by an encapsulation layer 1208. In FIG. 12F, the encapsulation layer 1208 may be planarized to form a layer 1210 that is the same height as the nanoscale pillars 1206a. In FIG. 12G, one or more top layers 1212 can be deposited over the encapsulated nanoscale pillars 1206a.

[0191] A second method of PSOMMA fabrication and integration is to bond the PSOMMA metasurface to an image sensor by a wafer bonding method. Figures 13A-13D show various steps of a wafer bonding method according to an embodiment of the present invention. In Figure 13A, an image sensor wafer 1302 is provided having a planarized or mostly planarized surface. In Figure 13B, a spacer layer 1304 is deposited on the planarized surface of the image sensor wafer 1302. The thickness of the spacer layer 1304 may determine the distance between the PSOMMA and the image sensor. The spacer layer 1304 may include a dielectric material (e.g., SiO2, Si3N4), a polymer layer, or other suitable layer that desirably has a refractive index less than 1.6 at the operating wavelength of the image sensor. In Figure 13C, a second wafer 1306 is provided that includes nanoscale pillars 1308 with PSOMMA. The nanoscale pillars 1308 of the second wafer 1306 may be fabricated using methods such as photolithography and / or wet or dry etching. The illustrated second wafer 1306 including the nanoscale pillars 1308 is illustrative only and other configurations are contemplated. For example, a layer may be between the second wafer 1306 and the nanoscale pillars 1308. Examples of nanoscale pillars fabricated on a substrate are described in U.S. Patent Application Publication No. 2019 / 0064532, entitled "Integration of Transmissive Surface Lenses," filed August 31, 2018, and incorporated by reference in its entirety for all purposes. The disclosed fabrication methods and various configurations of nanoscale pillars of a substrate may be utilized to fabricate the nanoscale pillars 1308 of the second separate wafer 1306. The second wafer 1306 may include silicon, glass, polymer, and / or other suitable materials. The second wafer 1306 may also have a spacer layer disposed on the front surface instead of the spacers in the first wafer or in addition to the spacers in the image sensor wafer 1302.

[0192] After separately fabricating the image sensor wafer 1302 and the second wafer 1306, the two wafers can be bonded together using a wafer bonding method. Wafer bonding methods include adhesive bonding, direct oxide bonding, eutectic, thermal compression bonding, and the like. FIG. 13D shows the image sensor wafer 1302 and the second wafer 1306 after the wafer bonding method. The wafers 1302, 1306 can be aligned with each other such that the individual metasurface lenslets can be aligned with corresponding pixels of the image sensor of the image sensor wafer 1302. The alignment tolerance of the lenslets to the pixels can be a fraction of the pixel size (or equal to the pixel size). In an embodiment, the alignment tolerance of the lenslets to the pixels can be less than 10% of the pixel size. In an embodiment, the second wafer substrate 1306 can be transparent. In an embodiment, the second wafer substrate 1306 can be a transparent material such as glass. If the second wafer substrate 1306 is transparent, the second wafer substrate 1306 can be part of the final integrated device.

[0193] In an embodiment, the second wafer 1306 may be opaque. Examples of opaque second wafer substrates include silicon. The second wafer substrate 1306 may be removed using methods including grinding, lapping, wet chemical etching, and / or dry chemical etching. After removal of the second wafer substrate 1306, the nanoscale pillars 1308 are transferred from the second wafer 1306 to the image sensor wafer 1302.

[0194] A third method of PSOMMA fabrication and image sensor integration is the die attach method. The steps of the die attach method begin with the same steps as those described above with reference to the wafer bonding method described in connection with FIGS. 13A-13C. After fabrication of the image sensor wafer 1302 and second wafer 1306, the second wafer may be singulated into individual dies. The individual singulated dies may then be bonded to the image sensor wafer 1302 using a die-wafer bonding process. FIG. 14A shows a plurality of second wafer dies 1402 bonded to the image sensor wafer 1302 according to an embodiment of the invention. Each individual second wafer die 1402 may be aligned with an appropriate feature of the image sensor wafer 1302. The alignment tolerance of the lenslet to pixel may be a fraction of the pixel size or equivalent to one pixel size. In an embodiment, the alignment tolerance of the lenslet to pixel may be less than 10% of the pixel size. After bonding of the individual dies to the image sensor wafer 1302, the image sensor wafer 1302 may be singulated into individual image sensor dies, resulting in a fully integrated image sensor-PSOMMA sensor. FIG. 14B shows the image sensor dies 1404 after the image sensor wafer 1302 has been singulated in accordance with an embodiment of the present invention. In an embodiment, a second wafer die 1402 may be bonded to a previously formed individual image sensor die to form an integrated image sensor-PSOMMA sensor. These individual image sensor dies may be formed by singulating the larger image sensor wafer 1302 prior to bonding to the second wafer die 1402.

[0195] FIG. 15 illustrates an exemplary fabricated PSOMMA sensor 1500 according to an embodiment of the present invention. The PSOMMA sensor 1500 includes a CMOS image sensor (CIS) wafer 1502. The PSOMMA sensor 1500 further includes a transparent substrate 1504. The transparent substrate 1504 can be glass. The nanopillars 1506 are positioned on the transparent substrate 1504. The air gap 1508 is positioned between the nanopillars 1506 and the CIS wafer 1502 such that the nanopillars 1506 are between the air gap 1508 and the transparent substrate 1504. The air gap 1508 is between the CIS wafer 1502 and the transparent substrate 1504. The air gap 1508 can include a thickness of 6 μm to 7 μm. The air gap 1508 can include a thickness of 3 μm to 4 μm. The PSOMMA sensor 1500 may include die-to-die or wafer-to-wafer overlay accuracy of 0.3 μm, which is the alignment tolerance during integration. The metasurface lens directs the sorted polarized light to the target image sensor pixel. Therefore, the metasurface lens needs to match / align with the image sensor with sub-pixel level accuracy. An air gap 1508 may be used to maintain flatness between the two wafers separated by less than 6 μm over a distance of 12 inches.

[0196] In one example, a spacer layer may be fabricated on the CIS wafer (described below in FIGS. 16A-16C), and a spacer layer may be fabricated on the nanopillars 1506 (described below in FIGS. 18A-18C). FIGS. 20A and 20B show the alignment process between the CIS wafer 1602 and the nanopillars 1506.

[0197] 16A-16C illustrate an exemplary method of fabricating a CIS wafer 1502 according to an embodiment of the present invention. In FIG. 16A, a CIS wafer 1602 is provided with a spacer layer 1604. The CIS wafer 1602 may include a previously fabricated image sensor. A second wafer 1608 is provided with an adhesive layer 1610. In FIG. 16B, the second wafer 1608 is contacted to the CIS wafer 1602 such that the adhesive layer 1610 contacts the spacer layer 1604. In FIG. 16C, the second wafer 1608 is removed and the adhesive layer 1610 is transferred to the top of the spacer layer 1604 such that the adhesive 1610a is only on the top of the spacer layer 1604 and not in the areas between the spacer layers 1604. The thickness of the spacer layer 1604 may be 6 μm or more. The CIS wafer 1602 may be 12 inches in diameter. The second wafer 1608 can be 12 inches in diameter. Channels 1612 can be between adjacent portions of the spacer layer 1604. The CIS wafer 1602 can include nanopillars. An example of this adhesive transfer process is described in U.S. Pat. No. 6,669,803, filed Sep. 29, 2000, entitled "SIMULTANEOUS PROVISION OF HEIGHT CONTROLLED BONDING MATERIAL AND ASSOCIATED STRUCTURES AT WAFER LEVEL," which is incorporated herein by reference in its entirety for all purposes.

[0198] 17 shows a plan view of a CIS wafer 1602 according to an embodiment of the invention. The CIS wafer 1602 includes a spacer layer 1604. An inner portion of each of the units of the spacer layer 1604 includes an imaging area 1702.

[0199] 18A-18C illustrate an exemplary method of fabricating a nanopillar wafer according to an embodiment of the present invention. In FIG. 18A, a nanopillar substrate 1802 includes a plurality of nanopillars 1804. A spacer layer 1806 is provided below the plurality of nanopillars 1804, such that it is on the opposite side of the nanopillar substrate 1802. A secondary wafer 1808 is provided with an adhesive layer 1810 directly facing the spacer layer 1806. In FIG. 18B, the secondary wafer 1808 is in contact with the nanopillar substrate 1802, such that the adhesive layer 1810 is in contact with the spacer layer 1806. In FIG. 18C, the secondary wafer 1808 is removed and the adhesive layer 1810 is transferred to the top of the spacer layer 1806, such that the adhesive 1810a is only on the top of the spacer layer 1806 and not in the areas between the spacer layers 1806. The width of the spacer layer 1806 may be 6 μm. Nanopillar substrate 1802 can be 12 inches in diameter. Secondary wafer 1808 can be 12 inches in diameter. Nanopillar substrate 1802 is provided with a spacer layer 1806. Secondary wafer 1808 is provided with an adhesive layer 1810. An example of this adhesive transfer process is described in U.S. Pat. No. 6,669,803, filed Sep. 29, 2000, entitled "SIMULTANEOUS PROVISION OF HEIGHT CONTROLLED BONDING MATERIAL AND ASSOCIATED STRUCTURES AT WAFER LEVEL," which is incorporated by reference in its entirety for all purposes.

[0200] 19 shows a plan view of a nanopillared substrate 1802 according to an embodiment of the invention. The nanopillared substrate 1802 includes a spacer layer 1806 in a grid orientation.

[0201] 20A and 20B show an exemplary method of fabricating a PSOMMA sensor according to an embodiment of the present invention. The PSOMMA sensor includes combining a nanopillar substrate 1802 of FIG. 18C with a CIS wafer 1602 of FIG. 16C. In FIG. 20A, the nanopillar substrate 1802 of FIG. 18C and the CIS wafer 1602 of FIG. 16C are positioned in close proximity to each other. The spacer layer 1806 of the nanopillar substrate 1802 and the corresponding adhesive 1810a have a width 2002, and the channel 1612 is between adjacent portions of the spacer layer 1604. The channel 1612 has a width 2004 that is greater than the width 2002 of the spacer layer 1806. In one example, the width 2004 of the channel 1612 can be 0.6 μm greater than the width 2002 of the spacer layer 1806. In FIG. 20B, the two wafers 1602, 1802 are bonded together with precisely interlocking spacer layers 1604, 1806 to provide a precisely aligned bond.

[0202] 21A and 21B show a process flow for manufacturing a CIS wafer according to an embodiment of the present invention. In FIG. 21A, a CIS wafer 2102 including a bonding pad 2104 is provided. In FIG. 21B, a dielectric layer 2106 is deposited on the CIS wafer 2102 including the bonding pad 2104. The dielectric layer 2106 may be a SiO2 layer. The dielectric layer 2106 may be deposited using a Plasma Enhanced Tetraethylorthosilicate (PETEOS) process. The dielectric layer 2106 may have a thickness of 5.5 μm. A planarization process may be used on the dielectric layer 2106. The planarization process may be a Chemical-Mechanical Polishing (CMP) process.

[0203] 22A and 22B show a process flow for fabricating a nanopillar wafer according to an embodiment of the present invention. In FIG. 22A, a nanopillar substrate 2202 including nanopillars 2204 is provided. In FIG. 22B, a dielectric layer 2206 is deposited on the nanopillar substrate 2202 including nanopillars 2204. The dielectric layer 2206 may be a SiO2 layer. The dielectric layer 2206 may be deposited using a plasma-enhanced tetraethyl orthosilicate (PETEOS) process. The dielectric layer 2206 may have a thickness of 5.5 μm. A planarization process may be used on the dielectric layer 2206. The planarization process may be a Chemical-Mechanical Polishing (CMP) process.

[0204] 23A-23H are fabrication processes for fabricating an imaging sensor using a CIS wafer fabricated using the process described in FIG. 21A and FIG. 21B and a nanopillar wafer fabricated using the process described in FIG. 22A and FIG. 22B according to an embodiment of the present invention. In FIG. 23A, a nanopillar substrate 2202 is bonded to a CIS wafer 2102 such that the nanopillars 2204 are separated from the bonding pads 2104 by a combined dielectric layer 2302, which includes the dielectric layer 2106 of the CIS wafer 2102 and the dielectric layer 2206 of the nanopillar substrate 2202. Some wafer-to-wafer bonding machines can only handle wafers with a bow of 250 μm or less. The dielectric layer 2106 of the CIS wafer 2102 and the dielectric layer 2206 of the nanopillars 2204, deposited using a tetraethyl orthosilicate (TEOS) process, can cause the wafer to bend (which would not allow wafer bonding). Advantageously, the planarization process of the dielectric layer 2106 of the CIS wafer 2102 and the dielectric layer 2206 on the nanopillars 2204 provides the ability to wafer bond the dielectric layer 21, dielectric layer 2106 of the CIS wafer 2102 to the dielectric layer 2206 on the nanopillars 2204. The wafer bonding process can yield an alignment accuracy of 200 nm.

[0205] In FIG. 23B, the nanopillar substrate 2202 is removed, leaving the nanopillars 2204 on the combined dielectric layer 2302. The nanopillar substrate 2202 may be removed by grinding, etching, and / or planarization (e.g., CMP). In FIG. 23C, a photoresist layer 2304 is deposited on the nanopillars 2204. The photoresist layer may be spin-coated on the nanopillars 2204. In FIG. 23D, the photoresist layer 2304 is patterned and the combined dielectric layer 2302 is etched to expose the bond pads 2104. In FIG. 23E, the photoresist layer 2304 is removed and a barrier seed layer 2306 may be deposited on the bond pads 2104, the sidewalls of the combined dielectric layer 2302, and the nanopillars 2204. In some embodiments, the barrier seed layer 2306 may be omitted. In FIG. 23F, a conductive layer 2308 is deposited on the barrier seed layer 2306. The conductive layer 2308 can be a copper (Cu) layer. The conductive layer 2308 can be deposited using an electrochemical plating (ECP) process. In FIG. 23G, the conductive layer 2308 is planarized to the nanopillars 2204. This planarization process can be a CMP process. In FIG. 23H, a Chip On Board (COB) process is performed. The COB process can be the wire bonding of the sensor directly to a printed circuit, which can be a printed circuit board. The printed circuit board can be flexible.

[0206] 24A-24C are manufacturing processes for manufacturing an image sensor utilizing a CIS wafer manufactured using the process described in FIG. 21A and FIG. 21B and a nanopillar wafer manufactured using the process described in FIG. 22A and FIG. 22B according to an embodiment of the present invention. FIG. 24A and FIG. 24B correspond to the steps of FIG. 23A and FIG. 23B. The description of these steps in FIG. 23A and FIG. 23B is related to the steps of FIG. 24A and FIG. 24B. In FIG. 24C, a Through Silicon Via (TSV) process is performed. Instead of wire bonding to bond pads on the front surface of the chip, holes can be formed from the backside of the chip / wafer to reach the bond pads on the front side, and then metawires can be bonded directly from the holes using solder balls on the backside of the wafer to achieve chip-scale packaging. In this case, there may be no bond pads open on the front side.

[0207] 25A-25H are fabrication processes for fabricating an image sensor according to an embodiment of the present invention. In FIG. 25A, a P-type substrate 2502 is provided. The P-type substrate 2502 may be highly doped with a P-type dopant. In FIG. 25B, a nanopillar layer 2505 may be formed on the P-type substrate 2502. The nanopillar layer 2505 includes embedded nanopillars 2504. In FIG. 25C, a crystalline layer 2506 is grown on top of the nanopillar layer 2505. The crystalline layer 2506 may be a P-type layer including a P-type dopant. The crystalline layer 2506 may be grown using epitaxial growth.

[0208] In FIG. 25D, a P-type doping process is performed, which results in a highly P-type doped layer 2508 on the crystal layer 2506. The P-type doping process can be an implantation process (e.g., an ion implantation process). In FIG. 25E, another crystal layer 2510 is grown on top of the highly P-type doped layer 2508. The crystal layer 2510 can be grown using epitaxial growth. In FIG. 25F, a CMOS layer 2512 can be formed on the crystal layer 2510. The CMOS layer 2512 can be a front-side circuit made with a general CMOS process. The crystal layer 2510 can be an underlayer for the CMOS layer 2512. In FIG. 25G, the device is bonded (e.g., by wafer bonding) to a carrier wafer 2514, and the CMOS layer 2512 is in direct contact with the carrier wafer. In FIG. 25H, the P-type substrate 2502 is removed. The P-type substrate 2502 may be removed by grinding, lapping, wet chemical etching, and / or dry chemical etching.

[0209] (Various exemplary PSOMMA configurations) FIG. 26 illustrates an example operation of an exemplary metasurface microlens array (MLA) according to an embodiment of the present invention. The design accounts for angular variation with the position of the MLA. Light entering from the metasurface MLA 2602 includes a chief ray angle (CRA) 2604 from the imaging optics or aperture, which may vary in the plane of the metasurface MLA 2602. This variation may be calculated or measured to give the CRA 2604 as a function of the angle and / or location of the MLA (e.g., as distance from the center of the MLA). A conventional refractive MLA may not account for this angular variation. A conventional refractive MLA may be designed to perform optically well or efficiently only for a CRA of 0 degrees. On the other hand, each metasurface lenslet of the metasurface MLA 2602 is optimized for a specific Area of ​​Illumination (AOI). In a conventional refractive MLA, each lenslet may include an aspheric term, or a more complex phase function. This approach for a conventional refractive MLA involves multiple refractive lenses / prisms that would add complexity. Therefore, the metasurface MLA enables solutions that include a variety of CRA2604s that may not be easily achievable using a conventional refractive MLA.

[0210] 27A shows an exemplary pixel arrangement for four polarizing pixels according to an embodiment of the present invention. The pixel arrangement includes multiple sets of polarizing pixels 2702 having a first pixel 2702a, a second pixel 2702b, a third pixel 2702c, and a fourth pixel 2702d with different polarizations. There are one or more normal pixels 2704 separating adjacent sets of polarizing pixels 2702. The normal pixels 2704 are non-polarized and / or non-split pixels, and are essentially blank or simply optically driven for focusing or filtering. In some embodiments, the number of normal pixels 2704 between adjacent sets of polarizing pixels 2702 may be more or less than those shown.

[0211] FIG. 27B illustrates an exemplary pixel arrangement for two polarizing pixels according to an embodiment of the present invention. The pixel arrangement includes multiple sets of polarizing pixels 2706 having a first pixel 2706a and a second pixel 2706b with different polarizations. The first pixel 2706a and the second pixel 2706b may include orthogonal polarizations. The sets of polarizing pixels 2706 may not be the same pair. For example, one pair of the sets of polarizing pixels 2706 may probe S1 polarization, one pair may probe S2 polarization, and one pair may probe S3 polarization. In an embodiment, depending on the transmission polarization, such as static polarized illumination or a known polarized illumination source, the probe polarization may be consistent with such one or more transmission polarization sources. There are one or more normal pixels 2708 separating adjacent sets of polarizing pixels 2706. In an embodiment, the number of normal pixels 2708 between adjacent sets of polarizing pixels 2706 may be more or less than those illustrated.

[0212] There may be a microlens array (MLA) that includes different microlenses associated with each of the pixels. The microlenses of the normal pixels 2704, 2708 and the microlenses for the polarizing pixels in the set of polarizing pixels 2702, 2706 may have the same primary image plane. The apertures of the polarizing pixels in the set of polarizing pixels 2702, 2706 may be different between the four polarizing pixel arrangement of FIG. 27A and the two polarizing pixel arrangement of FIG. 27B, so the F-number may be different for the different microlens arrays for the four polarizing pixel arrangement of FIG. 27A and the two polarizing pixel arrangement of FIG. 27B. In an embodiment, the MLA may be a metasurface or a refractive lens array. The MLA function may be implemented differently for the polarizing pixels than for the regular pixels. An open non-polarized simply driven or filtered optical element may overlay the regular pixels. The MLA may include multiple different focal length lenslets for depth by focus.

[0213] 27C shows an exemplary pixel arrangement for four polarizing pixels according to an embodiment of the present invention. The pixel arrangement includes multiple sets of polarizing pixels 2710 having a first pixel 2710a, a second pixel 2710b, a third pixel 2710c, and a fourth pixel 2710d with different polarizations. There are one or more normal pixels 2712 separating the first pixel 2710a, the second pixel 2710b, the third pixel 2710c, and the fourth pixel 2710d. In an embodiment, the number of normal pixels 2712 between adjacent sets of polarizing pixels 2702 may be more or less than those shown. The sets of polarizing pixels 2710 may be separated by one or more normal pixels 2712.

[0214] The designs described in relation to FIGS. 27A-27C may be utilized in implementing classification or filtering aspects, as described below.

[0215] FIG. 28A is a cross-sectional view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. As shown, the imaging device includes a microlens 2802 that directs light 2803 to a polarization splitting metasurface 2804. The microlens 2802 may be a portion of a microlens array. The polarization splitting metasurface 2804 splits the light 2803 into a first polarization 2806a and a second polarization 2806b. The first polarization 2806a and the second polarization 2806b may have orthogonal polarizations. An image sensor having a first range 2808a and a second range 2808b is positioned below the polarization splitting metasurface 2804. The first polarization 2806a is directed into the first range 2808a and the second polarization 2806b is directed into the second range 2808b. The microlens 2802 is offset from the first range 2808a and the second range 2808b such that the center of the microlens 2802 is between the first range 2808a and the second range 2808b.

[0216] Each microlens 2802 may cover at least half of the first range 2808a and the second range 2808b, with the overlapping metasurface lenslets 2804 diffracting light of a first polarization 2806a in a first direction into the first range and light of a second polarization 2806b in a second direction into the second range. The first polarization 2806a may be orthogonal to the second polarization 2806b.

[0217] FIG. 28B is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The imaging device includes a microlens and a polarization splitting metasurface as described in connection with FIG. 28A. The polarization splitting metasurface splits the light into a first polarization 2810a, a second polarization 2810b, a third polarization 2810c, and a fourth polarization 2810d. The imaging device includes an image sensor having a first range 2812a, a second range 2812b, a third range 2812c, and a fourth range 2812d. The first polarization 2810a is directed into the first range 2812a, the second polarization 2810b is directed into the second range 2812b, the third polarization 2810c is directed into the third range 2812c, and the fourth polarization 2810d is directed into the fourth range 2812d.

[0218] FIG. 28C is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The imaging device includes a first polarization splitter 2814a, a second polarization splitter 2814b, and a third polarization splitter 2814c structured similarly to the imaging device described in connection with FIG. 28A. As shown, each of the first polarization splitter 2814a, the second polarization splitter 2814b, and the third polarization splitter 2814c splits the light such that different polarizations are split in different directions. Each of the first polarization splitter 2814a, the second polarization splitter 2814b, and the third polarization splitter 2814c may operate on different polarizations. For example, the first polarization splitter 2814a may split the light into a first polarization and a second polarization, and the second polarization splitter 2814b may split the light into a third polarization and a fourth polarization.

[0219] FIG. 29A is a cross-sectional view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. As shown, the imaging device includes an array of microlenses 2902a, 2902b that direct light 2903 to a polarization splitting metasurface 2904. The polarization splitting metasurface 2904 splits the light 2903 into a first polarization 2906a and a second polarization 2906b. The first polarization 2906a and the second polarization 2906b may be orthogonal polarizations. An image sensor including a first range 2908a and a second range 2908b is positioned below the polarization splitting metasurface 2904. The first polarization 2906a is directed into the first range 2908a and the second polarization 2906b is directed into the second range 2908b. Light from the multiple metalenses 2902a, 2902b may be split into different portions of the polarization splitting metasurface 2904 such that a first polarization 2906a is directed into a first range 2908a and a second polarization 2906b is directed into a second range 2908b. As shown, in some portions of the polarization splitting metasurface 2904, the first polarization 2906a may be zero order light passing through the polarization splitting metasurface 2904 and the second polarization 2906b may be diffracted light redirected in a different direction. In other portions of the polarization splitting metasurface 2904, the second polarization 2906b may be zero order light passing through the polarization splitting metasurface 2904 and the first polarization 2906a may be diffracted light redirected in a different direction. One microlens 2902a is centered with the first range 2908a. One microlens 2902b is centered with a second area 2908b.

[0220] FIG. 29B is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The imaging device includes a microlens and a polarization splitting metasurface as described in connection with FIG. 29A. However, the polarization splitting metasurface splits the light into a first polarization 2910a, a second polarization 2910b, a third polarization 2910c, and a fourth polarization 2910d (vertically). As shown, the polarization splitting metasurface splits each polarization into a different direction, and the fourth polarization 2910d is the zeroth order light passing through the polarization splitting metasurface 2904. The imaging device includes an image sensor having a first range 2912a, a second range 2912b, a third range 2912c, and a fourth range 2912d. The different portions of the polarization splitting metasurface split the light so that all of the first polarization 2910a falls within a first range 2912a, all of the second polarization 2910b falls within a second range 2912b, all of the third polarization 2910c falls within a third range 2912c, and all of the fourth polarization 2910d falls within a fourth range 2912d.

[0221] FIG. 29C is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The imaging device includes a first polarization splitter 2914a, a second polarization splitter 2914b, and a third polarization splitter 2914c structured similarly to the imaging device described in connection with FIG. 29A. As shown, in each of the first polarization splitter 2914a, the second polarization splitter 2914b, and the third polarization splitter 2914c, the light is split such that different polarizations are split into different directions. Each of the first polarization splitter 2914a, the second polarization splitter 2914b, and the third polarization splitter 2914c may operate on different polarizations. For example, the first polarization splitter 2914a may split the light into a first polarization and a second polarization, and the second polarization splitter 2914b may split into a third polarization and a fourth polarization.

[0222] FIG. 30A shows a cross-sectional view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The device functions similarly to the device described in connection with FIG. 28A. As shown, the imaging device includes an array of microlenses 3002a, 3002b, 3002c that direct light 3003 to a polarization splitting metasurface 3004. The polarization splitting metasurface 3004 splits the light 3003 into a first polarization 3006a and a second polarization 3006b. The first polarization 3006a and the second polarization 3006b may be orthogonal polarizations. An image sensor including a first range 3008a, a second range 3008b, a third range 3008c, and a fourth range 3008d is positioned below the polarization splitting metasurface 3004. The first polarization 3006a is directed into a first range 3008a, and the second polarization 3006b is directed into a second range 3008b. Adjacent portions of the polarization splitting metasurface 3004 have opposite splitting capabilities, whereby the second polarization 3006b from adjacent portions of the polarization splitting metasurface 3004 is directed into the second range 3008b. The polarization splitting metasurface 3004 continues to repeat, such that the first polarization 3006a is directed into a third range 3008c, and the second polarization 3006b is directed into a fourth range 3008d. One microlens 3002a is offset from the first range 3008a and the second range 3008b such that its center is between the first range 3008a and the second range 3008b. One microlens 3002b is offset from the second range 3008b and the third range 3008c such that its center is between the second range 3008b and the third range 3008c, and one microlens 3002c is offset from the third range 3008c and the fourth range 3008d such that its center is between the third range 3008c and the fourth range 3008d.

[0223] FIG. 30B shows a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The imaging device includes the microlenses and polarization splitting metasurface described in relation to FIG. 30A. However, the polarization splitting metasurface splits the light into a first polarization 3010a, a second polarization 3010b, a third polarization 3010c, and a fourth polarization 3010d. The imaging device includes an image sensor having a first range 3012a, a second range 3012b, a third range 3012c, and a fourth range 3012d. The first polarization 3010a is directed into the first range 3012a, the second polarization 3010b is directed into the second range 3012b, the third polarization 3010c is directed into the third range 3012c, and the fourth polarization 3010d is directed into the fourth range 3012d.

[0224] FIG. 30C is a plan view of an imaging device including polarization splitting capabilities according to an embodiment of the present invention. The imaging device includes a first polarization splitting section 3014a, a second polarization splitting section 3014b, and a third polarization splitting section 3014c structured similarly to the imaging device described in connection with FIG. 30A. As shown, each of the first polarization splitting section 3014a, the second polarization splitting section 3014b, and the third polarization splitting section 3014c splits the light such that different polarizations are split in different directions. Each of the first polarization splitting section 3014a, the second polarization splitting section 3014b, and the third polarization splitting section 3014c may operate on different polarizations. For example, the first polarization splitting section 3014a may split the light into a first polarization and a second polarization, and the second polarization splitting section 3014b may split the light into a third polarization and a fourth polarization.

[0225] FIG. 31A illustrates a cross-sectional view of an imaging device including polarization filtering capabilities according to an embodiment of the present invention. As illustrated, the imaging device includes an array of microlenses 3102a, 3102b that direct light 3103 to a polarization filtering metasurface 3104. A portion of the polarization filtering metasurface 3104 is configured to transmit a first polarization 3106a. A portion of the polarization filtering metasurface 3104 is configured to transmit a second polarization 3106b. An image sensor including a first range 3108a and a second range 3108b is positioned below the polarization splitting metasurface 3104. The first polarization 3106a is directed into the first range 3108a and the second polarization 3106b is directed into the second range 3108b. One microlens 3102a is aligned with the first range 3108a and one microlens 3102b is aligned with the second range 3108b.

[0226] FIG. 31B shows a plan view of an imaging device including polarization filtering capabilities according to an embodiment of the present invention. The imaging device includes the microlenses and polarization filtering metasurface described in connection with FIG. 30A. However, different portions of the polarization filtering metasurface split the light into a first polarization 3110a, a second polarization 3110b, a third polarization 3110c, and a fourth polarization 3110d. The imaging device includes an image sensor having a first range 3112a, a second range 3112b, a third range 3112c, and a fourth range 3112d. The first polarization 3110a is directed into the first range 3112a, the second polarization 3110b is directed into the second range 3112b, the third polarization 3110c is directed into the third range 3112c, and the fourth polarization 3110d is directed into the fourth range 3112d.

[0227] FIG. 32A shows a cross-sectional view of an imaging device including polarization filtering capabilities according to an embodiment of the present invention. The imaging device shares many features with the imaging device described in connection with FIG. 31A. The imaging device includes an array of microlenses 3202a, 3202b that direct light 3203 to a polarization filtering metasurface. The polarization filtering metasurface includes a first area 3204a that transmits a first polarization of light and a second area 3204b that transmits a second polarization of light. The first area 3204a filters all of the polarizations from the light 3203 except the first polarization of light, and the second area 3204b filters all of the polarizations from the light 3203 except the second polarization of light. An image sensor including a first pixel 3206a and a second pixel 3206b is below the polarization filtering metasurface. The first range 3204a corresponds to the first pixel 3206a such that a first polarization of light is detected by the first pixel 3206a, and the second range 3204b corresponds to the second pixel 3206b such that a second polarization of light is detected by the second pixel 3206b.

[0228] FIG. 32B shows a cross-sectional view of an imaging device including polarization sorting capabilities according to an embodiment of the present invention. The imaging device shares many features with the imaging device described in connection with FIG. 28A. The imaging device includes an array of microlenses 3208 that direct light to a polarization sorting metasurface 3210. The polarization sorting metasurface 3210 sorts the light into a first polarization and a second polarization. The polarization sorting metasurface is separated from the light sensor by a back focal length 3214. The back focal length may be 10 μm. The light sensor includes a first pixel 3212a configured to detect the first polarization and a second pixel 3212b configured to detect the second polarization.

[0229] FIG. 32C shows a cross-sectional view of an imaging device including polarization sorting capabilities according to an embodiment of the present invention. The imaging device shares many features with the imaging device described in connection with FIG. 30A. The imaging device includes an array of microlenses 3216a, 3216b that directs light to a polarization sorting metasurface. The polarization sorting metasurface has a first extent 3218a configured to sort into a first polarization in a first direction and a second polarization in a second direction, and a second extent 3218b configured to sort into a second polarization in the first direction and the first polarization in the second direction. An image sensor is configured to receive light from the polarization sorting metasurface. The image sensor includes a first pixel 3220a configured to receive a first polarization from a first range 3218a, a second pixel 3220b configured to receive a second polarization from the first range 3218a and the second range 3218b, and a third pixel 3220c configured to receive a first polarization from the second range 3218b. There may be more microlenses as shown in FIG. 30A and a range of polarization sorting metasurfaces adjacent to those shown in FIG. 32C. There may be one microlens per pixel of the image sensor. The back focal length 3222 may be shorter than the back focal length 3214 of the image sensor in FIG. 32B. For example, the back focal length 3222 may be 5 μm compared to the back focal length 3214 of 10 μm.

[0230] FIG. 33A shows a plan view of an exemplary polarization filtering nanograting according to an embodiment of the present invention. In an embodiment, the polarization filtering nanograting may be interspersed with the polarization filtering metasurfaces described in connection with FIGS. 31A-31B and 32A. The polarization filtering nanograting includes different areas 3302a, 3302b, 3302c, 3302d corresponding to different pixels of the image sensor. Nanogratings may have several advantages, such as being easy to produce and being angle insensitive, which may favor an imaging device that includes both PSOMMA and nanogratings on the imaging sensor. In an embodiment, the microlens array function of the polarization pixels may be implemented as one or more metagratings, and the microlens array function may be implemented as one or more refractive lenses for the normal pixels.

[0231] FIG. 33B shows a plan view of an exemplary polarization sorting metasurface according to an embodiment of the present invention, which may be utilized as the polarization sorting metasurfaces described in connection with FIGs. 28A-C, 29A-C, 30A-C, 32B, and 32C. The polarization filtering metasurface includes different areas 3304a, 3304b, 3304c, 3304d corresponding to different pixels of the image sensor.

[0232] FIG. 34A shows a schematic plan view of an exemplary linear polarization sorted metasurface according to an embodiment of the present invention. This linear polarization sorted metasurface may be utilized in the polarization sorted metasurfaces described in connection with FIGS. 28A-C, 29A-C, 30A-C, 32B, and 32C. The polarization sorted metasurface diffracts different linear polarizations in different directions. In some embodiments, the different linear polarizations may be different orthogonal linear polarizations. As shown, the linear polarization sorted metasurface includes various metasurface elements 3402. The metasurface elements 3402 may have different dimensions (e.g., height and / or width). The metasurface elements 3402 may have the same orientation. The metasurface elements may be tilted at the same angle.

[0233] FIG. 34B shows a schematic plan view of an exemplary circular polarization sorting metasurface according to an embodiment of the present invention. This circular polarization sorting metasurface can be utilized in the polarization sorting metasurfaces described in connection with FIGS. 28A-C, 29A-C, 30A-C, 32B, and 32C. The circular polarization sorting metasurface diffracts different circular polarizations into different directions. In some embodiments, the different circular polarizations can be different opposite circular polarizations. In some embodiments, the polarization sorting metasurface can sort different elliptically polarized light into different directions. The circular polarization sorting metasurface includes various metasurface elements 3404. The metasurface elements 3404 can have the same dimensions (e.g., height and / or width). The metasurface elements can have different tilt angles with respect to the horizontal and / or vertical axes.

[0234] FIG. 34C shows a schematic plan view of an arbitrary polarization sorting metasurface according to an embodiment of the present invention. This arbitrary polarization sorting metasurface can be utilized in the polarization sorting metasurfaces described in connection with FIGS. 28A-C, 29A-C, 30A-C, 32B, and 32C. The arbitrary polarization sorting metasurface diffracts different arbitrary polarizations in different directions. In some embodiments, the different polarizations can be different orthogonal polarizations, or opposite polarizations. The arbitrary polarizations can be elliptical, circular, or linear. The linear polarizations can be vertical linear and horizontal linear. The linear or elliptical polarizations can be tilted. The circular polarizations can be right-handed and left-handed. The elliptical polarizations can be right-handed and left-handed. The arbitrary polarization sorting metasurface includes various metasurface elements 3406. The metasurface elements 3406 can have the same dimensions (e.g., height and / or width). The metasurface elements 3406 may have different tilt angles relative to the horizontal and / or vertical axes.

[0235] FIG. 35A shows a sparsely distributed PSOMMA sensor according to an embodiment of the present invention. A polarization splitting metasurface 3504 is sparsely distributed on a wafer 3502. The remaining area of ​​the wafer 3502 can be unpatterned or patterned with MLAs without polarization sorting or only metasurface MLAs. The wafer 3502 can be transparent glass. In an embodiment, the remaining area of ​​the wafer 3502 can be patterned with metasurface MLAs that do not split polarization. Such metasurface MLAs can have the same lenslets repeating throughout or can include lenslets with different focal lengths that can be used for autofocus or distance and depth measurements and / or calculations. One or more different filters can be applied to some or all of the lenslets. The sparse configuration can be asymmetric, irregular, or vary across the sensor space. In particular, for example, a less dense configuration in the center or a denser central configuration may be used in places to better capture facial features, or perhaps to better capture an image of the eyes. Different polar profiles may also be used in different areas (e.g., perhaps linear polarization at the edges and circular polarization in the center).

[0236] FIG. 35B shows a cross-sectional view of a sparsely distributed PSOMMA sensor according to an embodiment of the invention. A PSOMMA wafer 3502 containing a polarization splitting metasurface 3504 is integrated over an image sensor 3506. The image sensor 3506 is positioned below the polarization splitting metasurface 3504. The image sensor 3506 may include an R, G, B image sensor with corresponding R, G, B filters for corresponding color sensors. The image sensor 3506 has some areas where the RGB filters are removed making the area monochrome, and the PSOMMA wafer 3502 splits the light into pixels for the monochrome areas.

[0237] The image sensor 3506 may include a color filter, which may be blank, monochrome, or may pass near-infrared light to the portion that receives polarized light from the polarization splitting metasurface 3504. In an embodiment, the color from a low density PSOMMA pixel may be interpolated from nearby pixels. In this figure, some of the pixels have a Bayer pattern and some of the pixels are polarized (PSOMMA) pixels. When reconstructing the pixels, for pixels apparently below the PSOMMA pixel, the image may be reconstructed in full color by using the nearby RGB pixels as the color value at the PSOMMA pixel, even if the PSOMMA pixel does not directly capture the color.

[0238] In a low density format, the unused windows or pixels may simply be for intensity measurements and / or depth-from-defocus. Alternatively, the low density metasurface 3504 may have a metasurface for each pixel, but only some are polarization-based pixels and others have other properties such as focusing and deflection. A variety of different focal power lenslets can be used (e.g., long focal length lenslets) along with identifying spot sizes to identify distance, whereby image points are compared to find the most in-focus spot to determine distance or other characteristics known as Phase Detection AutoFocus (PDAF).

[0239] 36A shows an exemplary PSOMMA sensor according to an embodiment of the present invention. PSOMMA 3602 is positioned below color filter 3604. Each PSOMMA lenslet of PSOMMA 3602 has a range of color filter 3604 on top. The PSOMMA lenslet is optimized for the colors of the corresponding range of color filter 3604. As described above, PSOMMA 3602 directs light to different areas of image sensor 3606. Different image sides can be distinguished for different pixels of image sensor 3606.

[0240] FIG. 36B illustrates an exemplary PSOMMA sensor according to an embodiment of the present invention. The PSOMMA 3654 is positioned over the cover glass 3652. The PSOMMA 3654 may be positioned such that certain areas of the cover glass 3652 have PSOMMA lenslets and most areas allow light to pass through the exposed cover glass. The PSOMMA 3654 directs light to a particular color of the image sensor 3658. For example, the PSOMMA 3654 may direct light to green pixels of the image sensor 3658. The operation of the PSOMMA 3654 is described throughout the disclosure above. The image sensor 3658 may include RGB sensor pixels that may have built-in filters or may have separate color filters 3656 added. The image sensor 3658 may be a basic RGB sensor that utilizes RGB sensor colors. Portions of the cover glass 3652 that do not include the PSOMMA 3654 simply pass light to be captured as is normal in the image sensor 3658.

[0241] Although only a few embodiments of the present invention have been described in detail, it should be understood that the present invention may be embodied in many other forms without departing from the spirit or intent of the present invention. For example, the following embodiments are contemplated:

[0242] Clause 1. A polarized imaging device, comprising: a metasurface lenslet array comprising a plurality of metasurface lenslets, the plurality of metasurface lenslets comprising a plurality of first metasurface lenslets configured to diffract image light with an intensity proportional to a first polarization in a first direction and an intensity proportional to the second polarization in a second direction; and an image sensor positioned in an optical path of the first polarization and the second polarization, the image sensor comprising a plurality of image sensing units having a first image sensing unit positioned to sense the first polarization and a second image sensing unit positioned to sense the second polarization.

[0243] Clause 2. The polarization imaging device of clause 1, wherein the multiple image sensing units are different pixels and / or areas of an image sensor.

[0244] Clause 3. The polarization imaging device of clause 1, wherein the multiple image sensing units are different pixels and / or areas of multiple image sensors.

[0245] Clause 4. The polarized imaging device described in Clause 1, wherein the plurality of metasurface lenslets further comprises a plurality of second metasurface lenslets interspersed between the first metasurface lenslets and configured to diffract the image light with an intensity proportional to the third polarization in a third direction and an intensity proportional to the fourth polarization in a fourth direction, and the plurality of image sensing units further comprises a third image sensing unit positioned to sense the third polarization and a fourth image sensing unit positioned to sense the fourth polarization.

[0246] Clause 5. The polarized imaging device of clause 4, wherein the first polarization and the third polarization are the same polarization, and the second polarization and the fourth polarization are the same polarization.

[0247] Clause 6. The polarized imaging device described in Clause 1, wherein the first metasurface lenslet is further configured to diffract the image light with an intensity proportional to the third polarization in a third direction and with an intensity proportional to the fourth polarization in a fourth direction, and the plurality of image sensing units further comprises a third image sensing unit positioned to sense the third polarization and a fourth image sensing unit positioned to sense the fourth polarization.

[0248] Clause 7. The polarized imaging device of clause 1, wherein the first metasurface lenslet is further configured to pass zero-order light in a third direction.

[0249] Clause 8. The polarized imaging device of clause 7, wherein the third direction is different from the first direction and the second direction.

[0250] Clause 9. The polarization imaging device of clause 8, wherein the plurality of image sensing units further comprises a third image sensing unit configured to sense zero-order light.

[0251] Clause 10. A polarized imaging device as described in clause 7, wherein the third direction is the same as the first direction.

[0252] Clause 11. The polarized imaging device described in clause 1, further comprising one or more refractive lenses, the metasurface lenslet array being positioned between the refractive lenses and the image sensor.

[0253] Clause 12. The polarized imaging device described in clause 1, wherein the first polarization and the second polarization are different polarizations, and the first polarization and the second polarization are selected from the group consisting of linear polarization, oblique polarization, elliptical polarization, and circular polarization.

[0254] Clause 13. The polarized imaging device of clause 1, further comprising a microlens array, the metasurface lenslet array comprising a polarizing metasurface.

[0255] Clause 14. The polarized imaging device of clause 13, wherein the microlens array is configured to separate the image light into different pixels and the polarizing metasurface is configured to diffract a first polarization in a first direction and the second polarization in a second direction.

[0256] Clause 15. A polarized imaging device as described in Clause 14, wherein the polarizing metasurface overlaps with microlenses in the microlens array, and microlenses in the microlens array that do not overlap with the polarizing metasurface pass non-diffracted light to an image sensor, and the image sensor is configured to sense the non-diffracted light to measure the intensity of the non-diffracted light.

[0257] Clause 16. A polarized imaging device according to clause 13, wherein the microlens array is a planar microlens array layer.

[0258] Clause 17. The polarized imaging device of clause 13, wherein the microlens array and the polarized metasurface are positioned on a single substrate.

[0259] Clause 18. The polarized imaging device of clause 17, wherein the primary image plane is configured above a surface of the single substrate opposite the image sensor.

[0260] Clause 19. A polarized imaging device as described in clause 17, wherein the primary image surface is constructed within a single substrate.

[0261] Clause 20. A polarized imaging device as described in clause 13, wherein the microlens array comprises a metasurface element.

[0262] Clause 21. A polarized imaging device as described in clause 20, wherein the metasurface element is configured to receive a chief ray angle that varies across an imaging pupil of the polarized imaging device and to collimate the light passing through each microlens.

[0263] Clause 22. A polarized imaging device as described in clause 20, wherein the metasurface elements of the microlens array are configured to provide a refractive microlens effect.

[0264] Clause 23. A polarized imaging device as described in clause 13, wherein the microlens array comprises a conventional refractive microlens array.

[0265] Clause 24. A polarized imaging device as described in clause 13, wherein the microlens array comprises a combination of at least one conventional refractive microlens and at least one metasurface element.

[0266] Clause 25. The polarized imaging device of clause 1, further comprising a color filter positioned above or below the metasurface lenslet array.

[0267] Clause 26. A polarized imaging device as described in Clause 25, wherein color filters are positioned above the metasurface lenslet array and each filter light into a different color corresponding to a different metasurface lenslet of the plurality of first metasurface lenslets, and the metasurface lenslets receive color filtered light from the color filters.

[0268] Clause 27. The polarized imaging device of clause 25, wherein a color filter is positioned below the metasurface lenslet array to filter the diffracted first and second polarizations.

[0269] Clause 28. A polarized imaging device as described in clause 27, wherein the color filters include different ranges for filtering different wavelengths of light.

[0270] Clause 29. A polarized imaging device as described in clause 28, wherein the plurality of first metasurface lenslets are spaced apart on the cover substrate.

[0271] Clause 30. A polarized imaging device as described in Clause 29, wherein the spaced first metasurface lenslets are configured to output light onto a range of color filters that output light of the same color.

[0272] Clause 31. A polarized imaging device as described in Clause 30, wherein the spaced first metasurface lenslet outputs light to a range of color filters that outputs green light and a gap between the range of color filters that outputs green light, and the gap outputs red light or blue light.

[0273] Clause 32. A polarized imaging device as described in Clause 27, wherein the color filter includes different areas that output red, green, or blue light, and areas that output monochromatic or near-infrared light, and the plurality of first metasurface lenslets are spaced apart by the cover substrate, and the spaced apart first metasurface lenslets output light onto the areas of the color filter that output monochromatic or near-infrared light.

[0274] Clause 33. The polarized imaging device of clause 1, further comprising a microlens array including a plurality of individual microlenses that output collimated light to the metasurface lenslet array.

[0275] Clause 34. A polarized imaging device as described in Clause 33, wherein the multiple separated microlenses are positioned between adjacent image sensing units such that light from the multiple separate microlenses is diffracted by the multiple first metasurface lenslets in opposite oblique directions and enters the adjacent image sensing unit.

[0276] Clause 35. The polarized imaging device described in Clause 34, wherein the plurality of repeating metasurface lenslets further comprise a plurality of second metasurface lenslets configured to diffract a first polarization in a second direction and a second polarization in the first direction, and the first image sensing unit is further positioned to sense the first polarization diffracted from the plurality of second metasurface lenslets.

[0277] Clause 36. A polarized imaging device as described in Clause 33, wherein each of the plurality of separated microlenses is centered with one of the plurality of first metasurface lenslets such that a first polarization is transmitted through one of the plurality of first metasurface lenslets onto a first image sensing unit, and a second polarization is diffracted in a second direction onto a second image sensing unit.

[0278] Clause 37. The polarized imaging device of clause 1, wherein the first and second polarizations are orthogonal linear, circular, elliptical, or any polarization.

[0279] Clause 38. A polarized imaging device as described in clause 1, wherein the plurality of first metasurface lenslets are spaced apart with non-diffractive sections between adjacent first metasurface lenslets.

[0280] Clause 39. The polarization imaging device of clause 38, wherein the plurality of metasurface lenslets, the plurality of image sensing units configured to sense a first polarization and a second polarization are positioned between image sensing units of an image sensor configured to sense red light, green light, or blue light.

[0281] Clause 40. A polarized imaging device as described in Clause 39, wherein a plurality of first metasurface lenslets are configured to diffract light into a plurality of image sensing units configured to sense a first polarization and a second polarization, and into image sensing units configured to sense red light, green light, or blue light.

[0282] Clause 41. The polarized imaging device of clause 39, wherein the plurality of image sensing units configured to sense the first polarized light and the second polarized light are further configured to sense monochrome or near infrared light.

[0283] Clause 42. The polarized imaging device of clause 1, wherein the image sensor is a complementary metal oxide semiconductor (CMOS) image sensor, a charge-coupled device sensor, a silicon diode sensor, a cadmium sulfide sensor diode, an RGB sensor, an indirect time-of-flight (iToF) sensor, or a direct time-of-flight (dToF) sensor.

[0284] Clause 43. A method for producing a polarization imaging device, the method including providing an image sensor wafer, depositing a spacer layer on the imaging sensor wafer, depositing a metasurface layer on the spacer layer, and patterning the metasurface layer to form individual metasurfaces on the spacer layer.

[0285] Clause 44. The method of clause 43, further comprising depositing an encapsulation layer directly on each metasurface.

[0286] Clause 45. The method of clause 44, further comprising planarizing the encapsulation layer such that the encapsulation layer is in the same horizontal plane as the individual metasurfaces.

[0287] Clause 46. The method of clause 44, further comprising forming one or more top layers on the encapsulation layer and / or the individual metasurfaces.

[0288] Clause 47. A method for producing a polarization imaging device, the method comprising providing an image sensor wafer, providing a metasurface substrate having individual metasurfaces, and depositing a spacer layer on the imaging sensor wafer and / or the individual metasurfaces of the metasurface substrate.

[0289] Clause 48. The method of clause 47, further comprising bonding the metasurface substrate to the image sensor wafer.

[0290] Clause 49. The method of clause 48, wherein the metasurface substrate comprises a transparent substrate.

[0291] Clause 50. The method of clause 48, further comprising removing the metasurface substrate such that the individual metasurfaces remain attached to the image sensor wafer.

[0292] Clause 51. The method of clause 50, wherein removing the metasurface substrate comprises grinding, lapping, wet chemical etching, and / or dry chemical etching the metasurface substrate.

[0293] Clause 52. The method of clause 47, further comprising singulating the metasurface substrate into separate metasurface dies, bonding at least one of the metasurface dies to an image sensor wafer, and singulating the image sensor wafer into image sensor dies each with a bonded metasurface die.

[0294] Clause 53. A method of producing a polarization imaging device, the method comprising: providing a CMOS image sensor (CIS) wafer; positioning a first plurality of spacers on the CIS wafer; providing a first carrier wafer; positioning a first adhesive layer on the first carrier wafer; contacting the first plurality of spacers with the first adhesive layer such that adhesive is applied on top of the first plurality of spacers; providing a nanopillar substrate having a plurality of nanopillars; positioning a second plurality of spacers on the nanopillar substrate; providing a second carrier wafer; positioning the second adhesive layer on the second carrier wafer; contacting the second plurality of spacers with the second adhesive layer such that adhesive is applied on top of the second plurality of spacers; contacting the adhesive of the first plurality of spacers with the nanopillar substrate simultaneously with contacting the adhesive of the second plurality of spacers with the CIS wafer, and bonding the CIS wafer and the nanopillar substrate together.

[0295] Clause 54. The method of clause 53, wherein after contacting the first plurality of spacers with the first adhesive layer such that adhesive is applied to the tops of the first plurality of spacers, the adhesive is only on the tops of the first plurality of spacers and not in areas between the first plurality of spacers.

[0296] Clause 55. The method of clause 53, wherein after contacting the second plurality of spacers with the second adhesive layer such that adhesive is applied to the tops of the second plurality of spacers, the adhesive is only on the tops of the second plurality of spacers and not in areas between the second plurality of spacers.

[0297] Clause 56. The method of clause 53, wherein the first plurality of spacers comprises a pair of spacers forming a channel sized to receive a spacer of the second plurality of spacers.

[0298] Clause 57. The method of clause 56, wherein the first plurality of spacers and the second plurality of spacers interdigitate with each other such that one of the second plurality of spacers is positioned within one of the channels formed by the pair of spacers.

[0299] Clause 58. The method of clause 53, wherein the first plurality of spacers form a plurality of rectangular shapes on the CIS wafer.

[0300] Clause 59. The method of clause 58, wherein an interior of the rectangular shape forms an imaging area.

[0301] Clause 60. The method of clause 53, wherein the second plurality of spacers form a grid pattern on the nanopillar substrate.

[0302] Clause 61. The method of clause 53, wherein the first plurality of spacers and the second plurality of spacers form air gaps between the plurality of nanopillars and the CIS wafer.

[0303] Clause 62. A method of producing a polarization imaging device, the method including: providing a CMOS image sensor (CIS) wafer having bonding pads; depositing a first dielectric layer on the CIS wafer and the bonding pads; planarizing the first dielectric layer; providing a nanopillar substrate having a plurality of nanopillars; depositing a second dielectric layer on the plurality of nanopillars; planarizing the second dielectric layer; contacting the first dielectric layer and the second dielectric layer such that they are bonded together to form a combined dielectric layer; removing the nanopillar substrate to expose the plurality of nanopillars; partially etching the combined dielectric layer to expose the bonding pads; and forming a conductive layer electrically connected to the bonding pads through the combined dielectric layer.

[0304] Clause 63. The method of clause 62, wherein the first dielectric layer and the second dielectric layer are silicon dioxide layers.

[0305] Clause 64. The method of clause 62, wherein depositing the first dielectric layer and the second dielectric layer is performed by a tetraethyl orthosilicate (TEOS) process.

[0306] Clause 65. The method of clause 64, wherein the TEOS process is a plasma enhanced TEOS (PETEOS) process.

[0307] Clause 66. The method of clause 62, wherein planarizing the first dielectric layer and the second dielectric layer is performed by a chemical mechanical polishing (CMP) process.

[0308] Clause 67. The method of clause 62, wherein removing the nanopillar substrate is performed by a grinding, etching, or chemical mechanical polishing (CMP) process.

[0309] Clause 68. The method of clause 62, wherein partially etching the combined dielectric layer includes patterning the combined dielectric layer and etching the combined dielectric layer to expose the bonding pad.

[0310] Clause 69. The method of clause 62, further comprising growing a barrier seed layer on the bond pads, sidewalls of the associated dielectric layer, and the nanopillars.

[0311] Clause 70. A polarized imaging device comprises a microlens array having at least two microlenses, a polarized filtering metasurface having two or more polarized filtering ranges, and an imaging sensor having at least two ranges, wherein imaging light including one or more polarization states is directed by the microlenses onto the polarized filtering metasurface, and the polarized filtering metasurface is configured to direct the one or more polarization states onto the one or more ranges of the imaging sensor.

[0312] Clause 71. The polarized imaging device of clause 70, wherein the microlens array comprises refractive microlenses.

[0313] Clause 72. The polarized imaging device of clause 71, wherein the microlens array further comprises a metasurface configured to provide a refractive microlens effect.

[0314] Clause 73. The polarized imaging device of clause 70, wherein the microlens array comprises a metasurface configured to provide a refractive microlens effect.

[0315] Clause 74. The polarized imaging device of clause 70, wherein each of the at least two microlenses overlies a single area of ​​the one or more areas of the imaging sensor.

[0316] Clause 75. The polarized imaging device of clause 70, wherein each of the at least two microlenses overlies two or more sensor ranges of the one or more ranges of the imaging sensor.

[0317] Clause 76. The polarized imaging device of clause 70, wherein each of the at least two microlenses is on a single polarization range that is on one or more of the two or more polarization filtering ranges.

[0318] Clause 77. The polarized imaging device of clause 70, wherein each of the at least two microlenses overlies two or more polarized filtering ranges of the two or more polarized filtering ranges.

[0319] Clause 78. A polarized imaging device comprising: a metalattice array comprising a plurality of metasurface lenslets, the plurality of metasurface lenslets comprising a plurality of first metalattice lenslets configured to filter image light into a first polarization in a first range and a second polarization in a second range; and an image sensor positioned in an optical path of the first polarization and the second polarization, the image sensor comprising a plurality of image sensing units having a first image sensing unit positioned to sense the first polarization and a second image sensing unit positioned to sense the second polarization.

[0320] Clause 79. The polarized imaging device of clause 34, wherein the first polarization is orthogonal to the second polarization.

[0321] Clause 80. The polarized imaging device of clause 34, wherein each microlens covers half of two image sensing units using overlapping metasurface lenslets to diffract a first polarization in a first direction into a first image sensing unit and a second polarization in a second direction into a second image sensing unit.

[0322] Clause 81. The polarized imaging device of clause 80, wherein the first polarization is orthogonal to the second polarization.

[0323] (The Doctrine of Equivalents) Although the above description includes many specific embodiments of the present invention, these should not be construed as limitations on the scope of the present invention, but rather as examples of its embodiments. It is therefore to be understood that the present invention can be practiced otherwise than as specifically described without departing from the scope and spirit of the present invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive. The scope of the present invention should therefore be determined not by the embodiments described, but by the appended claims and their equivalents.

Claims

1. 1. A polarization imaging device, comprising: a metasurface lenslet array comprising a plurality of metasurface lenslets, the plurality of metasurface lenslets comprising a plurality of first metasurface lenslets configured to diffract image light with an intensity proportional to a first polarization in a first direction and with an intensity proportional to a second polarization in a second direction; an image sensor positioned in the optical path of the first polarized light and the second polarized light; Equipped with A polarization imaging device, wherein the image sensor comprises a plurality of image sensing units having a first image sensing unit positioned to sense the first polarization and a second image sensing unit positioned to sense the second polarization.

2. The polarization imaging device of claim 1 , wherein the multiple image sensing units are different pixels and / or areas of the image sensor.

3. the plurality of metasurface lenslets further comprises a plurality of second metasurface lenslets interspersed among the first metasurface lenslets, the plurality of second metasurface lenslets configured to diffract the image light with an intensity proportional to a third polarization in a third direction and with an intensity proportional to a fourth polarization in a fourth direction; 2. The polarized imaging device of claim 1, wherein the plurality of image sensing units further comprises a third image sensing unit positioned to sense the third polarization and a fourth image sensing unit positioned to sense the fourth polarization.

4. The polarized imaging device of claim 3 , wherein the first polarization and the third polarization are the same polarization, and the second polarization and the fourth polarization are the same polarization.

5. the first metasurface lenslet is further configured to diffract the image light with an intensity proportional to a third polarization in a third direction and with an intensity proportional to a fourth polarization in a fourth direction; 2. The polarized imaging device of claim 1, wherein the plurality of image sensing units further comprises a third image sensing unit positioned to sense the third polarization and a fourth image sensing unit positioned to sense the fourth polarization.

6. 10. The polarized imaging device of claim 1 , wherein the first metasurface lenslet is further configured to pass zero-order light in a third direction.

7. The polarized imaging device of claim 6 , wherein the third direction is different from the first direction and the second direction.

8. The polarization imaging device of claim 7 , wherein the plurality of image sensing units further comprises a third image sensing unit configured to sense the zero-order light.

9. The polarized imaging device of claim 6 , wherein the third direction is the same as the first direction.

10. 10. The polarized imaging device of claim 1, further comprising a microlens array, the metasurface lenslet array comprising a polarizing metasurface.

11. 11. The polarized imaging device of claim 10, wherein the microlens array is configured to separate the image light into different pixels, and the polarizing metasurface is configured to diffract the first polarization in the first direction and diffract the second polarization in the second direction.

12. 12. The polarized imaging device of claim 11 , wherein the polarizing metasurface overlaps with microlenses in the microlens array, and microlenses in the microlens array that do not overlap with the polarizing metasurface pass non-diffracted light to the image sensor, and the image sensor is configured to sense the non-diffracted light to measure the intensity of the non-diffracted light.

13. The polarized imaging device of claim 10 , wherein the microlens array is a planar microlens array layer.

14. The polarized imaging device of claim 10 , wherein the microlens array and the polarizing metasurface are positioned on a single substrate.

15. The polarized imaging device of claim 10 , wherein the microlens array comprises a metasurface element.

16. 11. The polarized imaging device of claim 10, wherein the microlens array comprises a combination of at least one conventional refractive microlens and at least one metasurface element.

17. 10. The polarized imaging device of claim 1, further comprising a microlens array including a plurality of individual microlenses that output collimated light to the metasurface lenslet array.

18. 20. The polarized imaging device of claim 17, wherein the plurality of separated microlenses are positioned between adjacent image sensing units, such that the light from the plurality of separate microlenses is diffracted by the plurality of first metasurface lenslets in opposite oblique directions into the adjacent image sensing units.

19. 20. The polarized imaging device of claim 18, wherein the plurality of repeating metasurface lenslets further comprises a plurality of second metasurface lenslets configured to diffract the first polarization in the second direction and diffract the second polarization in the first direction, and the first image sensing unit is further positioned to sense the first polarization diffracted from the plurality of second metasurface lenslets.

20. 10. The polarized imaging device of claim 1 , wherein the plurality of first metasurface lenslets are spaced apart with non-diffractive sections between adjacent first metasurface lenslets.

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