Multifunctional metasurface planar optics

Abstract

Metamaterial optical systems are described that include multifunctional metasurfaces formed of a plurality of meta-atoms. The multifunctional metasurfaces can exhibit two or more different optical functions for two or more different states of light incident on the metasurface. The different states of light include different polarizations, different wavelengths, and different angles of incidence. The different optical functions include distance sensing, focusing, divergence, image formation, and patterned light formation. The multifunctional metasurfaces can selectively impart different phase profiles to incident light beams depending on the state of the light beams.

Description

[0001] Cross-referencing related applications

[0002] This application claims the benefit of priority under 35 U.S. SC §119(e) to U.S. Provisional Application No. 63 / 283,803, filed November 29, 2021, entitled “Multifunctional Metasurface Flat Optics,” which is incorporated herein by reference in its entirety.

[0003] Government support

[0004] This invention was made with government support under license number HR0011-1-72-0029 granted by the U.S. Defense Advanced Research Projects Agency (DARPA). The government owns certain rights to this invention. Background Technology

[0005] Meta-optics continue to be developed as alternative optical components and systems to more traditional lens, phase mask, and filter optics. A meta-optics device comprises a patterned array of microscale structures on at least one surface of a substrate through which light passes. The shape of the structures and their arrangement on the surface can be designed to provide a desired far-field pattern or wavefront of the light field incident on the meta-optics device. Meta-optics devices can be designed to compensate for optical aberrations (e.g., to achieve high-resolution, ultra-wide field-of-view imaging). The advantage of meta-optics over conventional optical systems is that high-quality optics can be fabricated on substrates with flat surfaces using conventional microfabrication techniques, rather than grinding and polishing curved surfaces on one or more lenses, to form compound lenses with at most similar optical performance. Summary of the Invention

[0006] This invention relates to optical devices and systems, including subwavelength optics, metasurfaces, metamaterials, multifunctional planar optical devices, architectures, and systems that offer improved performance, new functionalities, and greater structural simplicity compared to conventional bulk optical systems. Such optical devices and systems can be used in computational imaging, three-dimensional (3-D) sensing, imaging, and other applications. More generally, applications of multifunctional metasurface planar optics include, but are not limited to, imaging, sensing, and optical computation techniques, such as machine vision, image classification, compressed sensing, multispectral imaging, light field imaging, computation, and polarization determination.

[0007] In some implementations, a meta-optical device can exhibit two or more optical states or optical functionalities. Each meta-optical device's optical state can capture different information about the scene (e.g., using different spectral or polarization channels) or perform different optical functions for subsequent data fusion or reconstruction (e.g., one state for imaging and another for performing edge detection). Edge detection can be implemented using a 2-D Laplacian operator phase profile used to perform second-order spatial differentiation. In another example, one optical state can be used to capture spatial information, and another state can be used to capture spectral / polarization information, etc.

[0008] The meta-optical device of the present invention may comprise a substrate and a multiplexing metasurface located on one side of the substrate. The multiplexing metasurface is configured to operate in at least two modes, which affect incident light in different ways depending on the properties of the light (e.g., its polarization, wavelength, angle of incidence, etc.). As an example, to realize a polarization-dependent multifunctional meta-optical device, the multiplexing metasurface is designed to provide different optical responses to light with different polarization states or different wavelengths (e.g., a first optical response for x-polarized light and a second optical response for y-polarized light) to obtain, for example, different information about the imaging scene. By providing different optical responses, the meta-optical device can effectively act as a wavefront coding element with different functions. Switching polarizers, filters, or illumination sources to change the polarization state, wavelength, or angle of incidence of the incident light can select the desired optical response of the multiplexing meta-optical device. In some embodiments, more than two optical responses from the meta-optical device are possible. In addition to different optical responses for different polarization states, meta-optical devices can also be designed to exhibit other optical responses for other states of incident light (e.g., different wavelength states, different incident angle states, etc.) to provide multiplexing functionality for multiple tasks.

[0009] The present invention can be implemented as an optical device comprising a substrate and a metasurface disposed on a first side of the substrate. The metasurface can be configured to impart a depth-sensitive phase profile to incident light in a first state and a depth-insensitive phase profile to incident light in a second state different from the first state.

[0010] Other embodiments of the present invention include parfocal zoom lenses. A parfocal zoom lens of the present invention may include a first transparent substrate, a second transparent substrate spaced apart from the first transparent substrate, a first metasurface disposed on a surface of the first transparent substrate, and a second metasurface disposed on a surface of the second transparent substrate. Alternatively, the first and second metasurfaces may be disposed on the first and second surfaces of the same transparent substrate. In both cases, the first and second metasurfaces are configured to generate a first light intensity / field distribution from light in a first state, and a second light intensity / field distribution different from the first light intensity / field distribution from light in a second state different from the first state. For example, the first and second metasurfaces may focus polarized light horizontally and vertically onto the same focal plane at different magnifications.

[0011] All combinations of the foregoing concepts and the additional concepts discussed in more detail below (provided that these concepts do not contradict each other) are contemplated as part of the inventive subject matter disclosed herein. All combinations of the claimed subject matter appearing at the end of this disclosure are also contemplated as part of the inventive subject matter disclosed herein. Terms expressly used herein and also likely to appear in any disclosure incorporated by reference should be given the meaning most consistent with the concepts disclosed herein. Attached Figure Description

[0012] Those skilled in the art will understand that the accompanying drawings are primarily for illustrative purposes and are not intended to limit the scope of the subject matter of the invention described herein. The drawings are not necessarily drawn to scale; in some cases, various aspects of the inventive subject matter disclosed herein may be exaggerated or enlarged in the drawings to aid in understanding different features. In the drawings, similar reference numerals generally refer to similar features (e.g., elements with similar functions and / or structures).

[0013] Figure 1A A perspective view depicts a 3-D imaging / sensor optical device architecture with a front metasurface for computational imaging and a rear metasurface for wide field-of-view (FOV) imaging.

[0014] Figure 1B Depicting Figure 1A A front view of the 3-D imaging / sensor optical architecture.

[0015] Figure 1C Five 9×9 unit cell arrays of elementary atoms arranged to form different supercells for the metasurface are depicted.

[0016] Figure 2A A perspective view of silicon atoms on polarization-sensitive, amorphous silicon dioxide suitable for use in the metasurface of the present invention is depicted.

[0017] Figure 2B Plots were created for x-polarized and y-polarized light. Figure 2A The difference between simulated phase profiles of the elementary atoms.

[0018] Figure 2C A portion of a metasurface layout with an array of polarization-sensitive elementary atoms is depicted, each polarization-sensitive elementary atom being similar to... Figure 2A The atoms in the material have different x and y dimensions.

[0019] Figure 3 This is a flowchart of an improved direct search process for selecting and arranging metaatoms across a metasurface.

[0020] Figure 4A A model is shown for simulating the performance of a depth-sensitive elemental optics device, which generates a focal point that rotates according to the depth or distance from the elemental optics device.

[0021] Figure 4B for Figure 4A A plot of the focal orientation of the optical element relative to depth (phase profile shown in the illustration).

[0022] Figure 4C Draws positioning at and Figure 4A The simulated point spread function (PSF) of a point source object at different depths of a primary optical device.

[0023] Figure 5A The process of image reconstruction and depth estimation using the meta-optical device of the present invention is illustrated.

[0024] Figure 5B The image shows a simulated 3D object (left side), using... Figure 5A The simulated reconstructed image (intermediate) of a 3-D object obtained by the meta-optical device and process of the present invention, and the double helix point spread function (DH-PSF) of the meta-optical device of the present invention.

[0025] Figure 5C The estimated depth of the 3-D object distance optics is plotted based on the DH-PSF image relative to the actual depth of the 3-D object distance optics.

[0026] Figure 6 This is a schematic diagram of a parfocal zoom lens with two multiplexed metasurfaces (MS-1 and MS-2), where solid and dashed lines indicate light with different properties (e.g., different polarization states).

[0027] Figure 7A The design and optical simulation results of a 10X parfocal zoom lens with two multiplexed metasurfaces are shown. The 10X parfocal zoom lens operates with near-diffraction-limited imaging performance at a FOV of 40 degrees in a first state (e.g., polarization 1).

[0028] Figure 7B It shows Figure 7A The 10X parfocal zoom lens operates with near-diffraction-limited imaging performance at a FOV of 4 degrees in the second state (e.g., polarization 2).

[0029] Figure 8 Examples of optical systems that include multifunctional optical components are described. Detailed Implementation

[0030] I. Computational optical components for 3D imaging

[0031] The 3-D imaging / sensing architecture based on computational metasurface planar optics offers significantly enhanced performance and an ultra-compact planar shape factor. This approach combines ultra-wide field of view (FOV) and computational imaging capabilities in a few-to-one optical system, although in some cases two or more optics can be used. The compact, multifunctional meta-optical device features: (1) a multifunctional, multiplexed planar optics design; (2) an ultra-wide FOV (e.g., from 100° to nearly 180°) with high-resolution imaging; (3) extended depth of field (EDOF); and (4) a few-to-one, ultra-compact, lightweight optical architecture. Multiplexed meta-optics and wide FOV characteristics can be decoupled for various implementations to provide different FOVs, such as 1°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, or any subrange from 1° to 180°. Advantageously, meta-optics with one or more metasurfaces can simultaneously achieve wide FOV and multiplexed optical functions without any changes to the meta-optics during use.

[0032] The optical structures and metasurface designs used in such multifunctional meta-optical devices are compatible with casting manufacturing, thus allowing for low-cost fabrication and integration with commercial image sensors and light emitters within ultra-compact sensor modules. For example, meta-optical sensor modules can have a form factor between 0.1 cubic centimeters (cc) and 10 cc in some cases, or between 0.1 cc and 1 cc in others.

[0033] Existing 3D sensors typically rely on active illumination and / or triangulation techniques to sense depth, as can be done, for example, in structured light (SL), time-of-flight (TOF), and passive / active stereo imaging methods. Alternatively, depth-of-defocus (DFD) methods can be used to extract depth information, analyzing axially correlated image aberrations caused when the imaging system is defocused. While simplifying optical system configuration, such DFD methods either reduce depth accuracy or require dynamic image acquisition because the depth-resolving power of conventional lenses is essentially limited by their point spread function (PSF), which changes slowly with the depth of the object. The term "depth" is generally used in the art to refer to the distance of an object from an imaging lens or imaging system.

[0034] Alternative methods for determining depth have been developed by spatially engineering the PSF to enhance its depth-discriminating capabilities. Among different methods, the Double Helix PSF (DH-PSF) method has successfully demonstrated effectiveness in depth discrimination by generating a 3-D PSF that produces two lobes that rotate continuously with the object's distance from the imaging lens or imaging system. DH-PSF functionality can be achieved by using a spatial light modulator (SLM) that switches its phase profile between the DH-PSF and a depth-insensitive phase, or by using a dual-aperture metasurface configuration with a pair of laterally adjacent phase masks that produce side-by-side images captured by an image sensor. While both methods demonstrate improved performance in terms of depth accuracy and depth of field, the former involves a rather complex optical setup (involving an SLM, a 4f correlator, and an imaging lens), and the latter relies on a shared aperture that ultimately sacrifices efficiency and camera compactness, and is difficult to integrate with other optical features.

[0035] Figure 1A and Figure 1BA multifunctional, multiplexed metasurface planar optics device, also known as meta-optics 100, is demonstrated, exhibiting significantly enhanced optical performance and potentially very small optical system size. The meta-optics device comprises a single planar transparent substrate 105 having a first multiplexed metasurface 110 (for computational imaging) positioned on the front side (first surface) and a second metasurface 120 (for wide FOV imaging) positioned on the back side (second surface). The front multiplexed metasurface is configured to operate in at least two modes (e.g., providing at least two optical functions), which encode the front of the incident beam in different ways according to the properties of the incident light (e.g., its polarization, wavelength, angle of incidence, etc.). Regarding the angle of incidence, different optical functions can be induced for different angle of incidence values ​​(e.g., two different elevation angles) and / or for different angle of incidence directions (e.g., the same elevation angle at two different azimuth angles). Additionally, different optical functions can be induced for different orbital angular momentum. Encoding can be used to assist in image post-processing and / or to modulate light in different ways to achieve different optical functions.

[0036] In some cases, beams 160 with different angles of incidence (AOI) can be generated by the first metasurface 110 and subsequently transmitted to the back-side second metasurface 120 and focused onto a flat (i.e., smooth) image plane 140 where the image sensor is located. However, in some embodiments, the image plane can be curved in one dimension (cylindrical, parabolic, etc.) or two dimensions (spherical, parabolic, etc.). In some cases, the focal points can be spatially separated on the image plane 140, such that their corresponding electronic images (e.g., which can be captured by a CCD camera or CMOS imaging array) can be operated independently of each other. The separation of the beams can depend on the polarization, wavelength, or angle of incidence of the light incident on the first metasurface 110.

[0037] Now consider some exemplary multi-functional meta-optical devices. The first example is a multi-functional meta-optical device that can switch between at least two optical functions based on the polarization state or orbital angular momentum (OAM) state of the incident light. The polarization state can include conventional orthogonal states, such as vertical and horizontal (or sagittal and tangential), right circular and left circular polarization, and various ellipsoidal polarization states. For polarization-multiplexing metasurfaces, switching between polarization states can effectively select the specific functionality (e.g., converging or diverging lens) designed for the metasurface. Polarization switching can be accomplished by rotating a polarizer in the incident beam path of an unpolarized source, rotating a half-wave plate in the beam path of a polarized source, rotating the polarized source, etc. In some cases, controllable liquid crystal devices can be used to change the polarization state of the incident light or act as filters. In such embodiments, changing the polarization state effectively alters the phase profile presented by the metasurface. In other cases, filters or pixelated filter arrays with different filtering properties can be integrated onto an image sensor or sensor pixel array, such that images corresponding to different light properties (e.g., polarization state or wavelength) can be captured by different sensors or sensor pixels. OAM-selective metasurfaces can be constructed to capture images with different OAM modes. Such metasurfaces can be further stacked together to form multiplexed OAM metasurfaces to capture images with multiple OAM modes.

[0038] Polarization switching (and efficient switching of the phase profile of the metasurface) allows the front multiplexing metasurface to capture different information about the scene, thereby enabling high-quality 3D scene reconstruction or information extraction via post-processing. For 3D sensing or passive ranging, for example, the front multiplexing metasurface can be designed to have at least two different phase profiles under light with different polarizations: (1) a depth-sensitive phase profile that produces two foci that rotate as the object shifts in depth; and (2) a depth-insensitive phase profile that produces a depth-insensitive response, as further described below. Assuming eight phase levels are used to cover a 2π phase range, the front multiplexing metasurface can contain a total of 8 2 = 64 different types of elementary atoms, each of which provides different combinations of two phase values ​​under different polarized light. If more phase profiles (i.e., optical functions) and / or phase levels are included, then to achieve an arbitrary phase profile with m discrete phase levels, a total of m can be used. n Individual atomic design.

[0039] Metasurfaces can be designed to be polarization-insensitive (e.g., symmetric atomic geometries for different polarizations) to maintain a wide light collection angle in all cases, or they can be designed to be polarization-sensitive to further multiplex the computational process. In addition to polarization, metasurfaces can also be designed to impart different phase profiles based on other properties of the incident light (e.g., wavelength, angle of incidence, etc.). These phase profiles can provide additional multiplexing functionality to accomplish multiple tasks, including additional optical processing / computational tasks assigned to each metasurface.

[0040] Depending on the properties of the incident light, the elementary atoms can also be configured to provide different functions / responses when used as individual elementary atoms or groups of elementary atoms (i.e., supercells). Figure 1C Examples of five different supercells 170-1, 170-2…170-5 are depicted, each composed of 81 unit cells 175 of free elementary atoms. Each unit cell 175 may contain a number of elementary atoms. Any number of unit cells 175 constituting the supercell 170 may exist. Such supercells of elementary atoms may be in-plane (e.g., elementary atoms are located on the same surface across the substrate), out-of-plane (e.g., elementary atoms are located on different surfaces or layers on the substrate above each other), or a combination of both. Multiple layers of elementary atoms may also be stacked to provide different optical functions or responses.

[0041] A metasurface may comprise a plurality of supercells 170 arranged in an array. The supercells 170 may be configured to provide different collective optical responses depending on the properties of the incident light. For example, the metasurface may be characterized as having at least two spacings and operating at at least two wavelengths. For example, individual atoms within a unit cell 175 and / or their spacing or pitch are configured to modulate light having a first wavelength (e.g., a smaller wavelength), while groups of multiple atoms (e.g., unit cell 175 or supercell 170) and / or their spacing or pitch are configured to modulate light having a second wavelength (e.g., a larger wavelength).

[0042] Different supercells 170 can provide different optical functions. For example, the unit cell 175 of supercell 170-2 can be rearranged to form different supercells 170-3, 170-4, and 170-5, thereby providing different optical functions, such as... Figure 1C As depicted in [the diagram]. The unit cell 175 and supercell 170 can be designed to operate at a first wavelength and a second wavelength, respectively. For Figure 1CThe four supercells 170-2, 170-3, 170-4, and 170-5 shown in the diagram, while the unit cell 175 can provide different phase profiles (transitions across the supercell) for a beam of light of a first wavelength incident on the supercell 170, a beam of light at a second wavelength can exhibit a uniform phase profile (no phase change across the supercell). With different arrangements of the unit cells, metasurfaces can be formed to provide multiplexing functionality at two or more wavelengths. For example, a first beam of light at a first wavelength incident on the supercell can undergo a first optical transformation (e.g., a collimated beam at the first wavelength can diverge through the supercell), while a second beam of light at a second wavelength incident on the same supercell can undergo a second optical transformation different from the first optical transformation (e.g., a collimated beam at the second wavelength can converge through the supercell).

[0043] Figure 2A , Figure 2B and Figure 2C An exemplary meta-atomic design and its performance at a wavelength of 670 nm are shown. Figure 2A An exemplary atomic atom 200 is depicted comprising rectangular blocks 210 of a high-refractive-index material (e.g., amorphous silicon) on a low-refractive-index substrate 205 (e.g., fused silicon dioxide). Changing the geometry of the blocks 210 in the atomic atom 200 array provides different polarization-dependent phase responses under x-polarized and y-polarized light, as shown in… Figure 2B The drawing is shown in the image. Figure 2B Each data point in the plot is designed for a single meta-atom in the same array of meta-atoms 200, where each meta-atom 200 has a length y and a width x as indicated by the axis on the plot. The phase difference imparted by the meta-atom 200 between x-polarized and y-polarized light incident on the array is plotted as a relative phase value in radians, indicated by gray shading. The entire plot contains meta-atoms with different lateral dimensions (length y and width x). The meta-atoms have a fixed height of 450 nm and a fixed spacing of 300 nm. In this example, the meta-atoms 200 are asymmetrical about the optical axis extending vertically through the center of the rectangular block 210, which gives the meta-atoms different responses to different polarizations. For symmetrical meta-atoms (e.g., cylinders), different wavelengths can be used to elicit different optical responses from the meta-atoms.

[0044] Figure 2C This image shows a portion of a polarization-sensitive metasurface 250 composed of meta-atoms 200 from a meta-atom library. The shape of blocks 210 of meta-atoms 200 can vary across metasurface 250. Arrays of meta-atoms can be arranged to form (e.g., supercells) unit cells or building blocks that constitute the entire polarization-sensitive metasurface of a meta-optics device. Polarization-sensitive metasurfaces can be generated using inverse design methods to extract information about a scene that will be imaged or otherwise sensed using meta-optics.

[0045] According to one embodiment, the entire polarization-sensitive metasurface is designed to impart a depth-sensitive phase profile (for one polarization) capable of generating two focal points from a single point source, wherein the two focal points rotate according to the depth / distance of the point source from the metasurface. As the distance between the point source and the metasurface changes, the two focal points rotate about the optical axis of the metasurface in the image plane according to the depth of the object. While the metasurface can be designed to provide optical transformations similar to a double-helix PSF (DH-PSF) (for one polarization) based on phase-only superposition of Laguerre-Gauss modes, the performance of the metasurface is typically limited by background noise, operates within a finite distance range between the metasurface and the point source, and provides limited depth accuracy. To overcome these limitations, the inventors utilize a gradient-based numerical optimization method to enhance and precisely engineer the metasurface, which can provide an improved DH-PSF intensity distribution in response to changes in the distance between the object and the metasurface. Using gradient-based numerical optimization methods, inventors can customize reverse design objectives to achieve improved depth detection accuracy and / or improved metasurface-to-object distance range, high-resolution imaging, improved optical efficiency and increased signal-to-noise ratio (SNR), and compliance with manufacturing tolerances.

[0046] To improve optical performance and allow for increased design complexity compared to existing methods, an end-to-end design framework is used to efficiently develop meta-optical systems that can provide multiple optical functions with a single optics element. For example, one of the optical functions could be a DH-PSF (Hydro-Optical-Focused Filter). Figure 3 An improved Direct Binary Search (DBS) process 300 (perturbation-based iterative method) is demonstrated for selecting and arranging meta-atoms to form at least one metasurface for a meta-optical device. In this process, meta-atoms are used as building blocks to construct at least one multiplexed, multifunctional metasurface to extract various information about a scene that will be imaged or otherwise sensed by the meta-optical device. The DBS process 300 begins with an initial metasurface design for a specific optical function (to impart an initial phase profile 310 to the incident beam). The process 300 then sequentially replaces each meta-atom across the metasurface with alternative designs from different meta-atom design libraries, employing the design that produces optimal performance. Typically, the size, geometry, symmetry, spacing, and distance between meta-atoms (i.e., meta-atom spacing) of the meta-atoms can be varied to produce the desired performance. In some cases, a specific weighted quality factor (FOM) is first defined and applied for performance evaluation (e.g., PSF intensity distribution, wavefront aberration function, light intensity distribution, efficiency, inter-state contrast, etc.). One or more meta-optical device parameters (e.g., meta-atomic design, meta-atomic spacing, meta-atomic size, meta-atomic material, optical response, meta-optical device size, meta-optical device shape, meta-optical device geometry, etc.).

[0047] Metasurface optimization begins with the initial phase profile 310 and / or amplitude distribution of the incident beam imparted by the metasurface for selected input light conditions (e.g., polarization, wavelength, bandwidth, OAM, and / or angle of incidence). In each iteration, the design parameters are perturbed randomly or in a specific sequence (Action 320). The FOM (Form of Optical Model) is continuously evaluated using an optical diffraction integral model (or other optical simulation or analysis model) to simulate the output light field from the metasurface. The output light field can be evaluated to determine (Action 335) whether the perturbation on the unit cell improves the output light field and the optical performance of the meta-optics. If the substitution does not improve the optical performance, the substitution is discarded (Action 350), and the meta-atom library is checked to determine (Action 345) whether all meta-atom designs from the library have been tried. If the substitution improves the performance, the new meta-atom is retained (Action 340), and the meta-atom library is checked to determine (Action 345) whether all meta-atom designs from the library have been tried. The meta-atom designs in the library can contain meta-atoms of different shapes, sizes, spacings, and / or materials. If all designs from the library have been tried for the i-th atom, process 300 can move to the next (i+1)-th atom in the array and repeat the steps that started with the sequential replacement of the atom (action 320). Process 300 continues until, according to process 300, all the atomes of the metasurface have been perturbed at least once.

[0048] In some cases, process 300 can be performed atom-by-atom on a per-atom basis for each atom in the metasurface (i.e., moving through each atom in the metasurface one at a time). In other cases, process 300 can be performed atom-by-atom on a per-unit cell basis, and the unit cell can be progressively tuned by rerunning process 300 for each unit cell. In some cases where identical unit cells are distributed on the metasurface, the same i-th atom in each identical unit cell and at the same position can be completely replaced in the same step (action 320) of replacing the atom during process 300 iterations. According to some embodiments, identical atoms (having the same shape and size) in the metasurface can be completely replaced in the same step (action 320) of replacing the atom during process 300 iterations to improve the optical performance of the meta-optics, regardless of whether the meta-optics contains a unit cell.

[0049] For a multiplexed, multifunctional metasurface in which individual atoms can exhibit different responses under different states (e.g., under different input light properties), multiple objectives are included in the FOM and can be improved simultaneously or sequentially using the DBS process 300. The process 300 may terminate when a predetermined (e.g., user-specified) FOM improvement threshold (decision 337) is achieved for at least one of the optical functions provided by the meta-optics, or when the maximum number of iterations is reached, or when the meta-atom library is exhausted for each meta-atom of the metasurface. The FOM can be one or more properties of the point spread function (e.g., intensity distribution, Strehl ratio, FWHM, etc.) and / or one or more properties of the modulation transfer function (e.g., contrast at a specific spatial frequency or a set of spatial frequencies). In some cases, one or more other metrics may be used additionally or alternatively for the FOM (e.g., background noise, phase error, etc.). Preferably, the predetermined FOM improvement is achieved before the maximum number of iterations is reached or the library of all meta-atoms is exhausted. Using this inverse optimization method, high-performance phase profiles can be designed and customized to extract different information about a scene (e.g., depth-sensitive, extended depth of focus, large field of view, or broadband metasurface phase profiles), which are significantly more general or computationally more efficient than traditional analysis or brute-force generation solutions, respectively.

[0050] Figure 4A , Figure 4B and Figure 4C The performance of an exemplary single-layer, depth-sensitive meta-optics device (without a wide FOV metasurface) with a 1 mm lens diameter and a target distance sensing range from 5 cm to 25 cm is shown. The meta-optics device reorients (rotates) the image based on the distance between the object being imaged and the metasurface of the meta-optics device. In this example, the object being imaged is a point source, and it is imaged as two separate point sources rotated according to the distance of the object to the metasurface. One way to form two separate images of a single point source with a single meta-optics device is to superimpose two meta-atomic patterns on the meta-optics device, where each pattern corresponds to a lens focused at a position different from the other meta-atomic pattern and its corresponding lens. For Figure 4A The elemental optics, for a distance change of 20cm, rotate the two imaging point sources by approximately 80 degrees. The elemental optics provide DH-PSF optical functionality, such as... Figure 4C This can be seen in a series of images.

[0051] exist Figure 4BIn the diagram, the solid line represents the target response of the meta-optics designed using the DBS process 300 described above. The plotted points represent simulation results using optical analysis based on optical diffraction integrals. The meta-optics imparts a phase profile that generates a DH-PSF to light in a first polarization state (e.g., horizontally polarized light). Simulation results show that the correlation between the rotation angles of the two focal points and depth accurately matches the target performance, covering angular and depth ranges of approximately 80° and 20 cm, respectively. These results demonstrate that object depth can be sensed over a wide depth range using meta-optics based on the DH-PSF rotation angle of the recorded image.

[0052] Figure 4A The meta-optical devices can further impart a cubic phase profile to light in a second polarization state (e.g., vertically polarized light), exhibiting a nearly invariant object-to-metasurface distance response. Thus, the lens provides both depth-sensitive and depth-insensitive phase profiles for polarization multiplexing. Furthermore, other optical computational functionalities can be incorporated into multiple states of the multifunctional metasurface design for additional data extraction; for example, the metasurface can encode the phase profile as a 2-D Laplacian operator to perform second-order spatial differentiation for edge detection and image differentiation.

[0053] Figure 5A A process 500 for image reconstruction and depth estimation based on light focused onto a focal plane imaging array or other detector array by a suitably designed multifunctional meta-optics is illustrated. Two original sub-images 510-1 and 510-2 under different polarizations are first captured by the depth-sensitive and depth-insensitive optical functionalities of the meta-optics (e.g., as described above regarding...). Figures 4A to 4C(As described). The distance-insensitive functionality is used as an extended depth-of-field (EDOF) lens for the first polarization. The distance-sensitive functionality is used as a DH-PSF lens. An initial lateral image 520 is generated by deconvolving the original depth-insensitive sub-image 510-1 using a randomly selected point spread function (PSF) 515 generated for the EDOF lens within its designed depth-of-field range. Additionally, a sub-image 510-2 captured by the DH-PSF functionality of the meta-optics is deconvolved using the selected DH-PSF to estimate the distance to at least one object in the image. The selected DH-PSF determines the estimated distance, and the object with the sharpest features (e.g., the least blurred edges) is located at the estimated distance. If all objects (or objects of interest) in the image are at the same distance, several iterations of selecting the DH-PSF and deconvolving the distance-sensitive sub-image 510-2 can be performed to obtain the estimated distance to the object. Once the estimated distances are obtained, the EDOF PSF used for deconvolution of the distance-insensitive sub-image 510-1 can be modified to improve the lateral image 520. An iterative loop of selecting the DH-PSF and modifying the EDOF PSF can be performed to improve the estimated distances to one or more objects in the lateral image 520 and improve the quality of the lateral image 520.

[0054] As an example, scenario I can be performed by solving the Tikhonov regularized least squares problem. S Image reconstruction:

[0055]

[0056] in Let y be the unknown variable, which is the image formed by integrating over sensor pixels with added noise (I, obtained using a diffraction integral model), S be the pixel integration and sampling operator, and p be the PSF of a certain information channel (e.g., depth, field of view, wavelength, polarization, etc.). This is an estimate of the scene image, and γ is the regularization parameter. This problem can be solved in closed-form using Wiener filtering with assumed circular boundary conditions:

[0057]

[0058] in It is the optical transfer function of p.

[0059] When the reconstruction process involves co-optimization using bilateral variables and multifunctional meta-optical devices, a differentiable loss function L (e.g., the mean square error relative to the true image) can be defined on the reconstructed image:

[0060]

[0061] Because the reconstruction is parameterized via PSF, the multiplexed meta-optical system optimization and post-processing stages are directly connected end-to-end, allowing for a joint optimization process for computational image reconstruction. Other deconvolution / reconstruction methods, such as machine learning-based approaches, can also be utilized.

[0062] Figure 5B and Figure 5C Preliminary results were presented, and their indications can be used Figure 5A The process achieves high-accuracy depth estimation and high-quality image reconstruction over a wide depth range. Compared to conventional lenses without wavefront encoding, multifunctional meta-optics with multiplexed PSFs (e.g., EDOF PSF and DH-PSF) can provide improved distance sensing, extended depth of field, and broadband operation. Multifunctional metasurfaces (computational planar optics layers) can be easily fabricated on the front surface or aperture of wide FOV metalens architectures to achieve wide-angle, high-resolution, extended depth of field 3D imaging.

[0063] An optical sensing / imaging system may include a multifunctional meta-optical device, a switchable filter (e.g., a switchable polarization or wavelength filter), and at least one image sensor (e.g., a CMOS or CCD imaging array) located at the image plane of the meta-optical device. Depending on the properties of the light incident on the system, the meta-optical device can provide different optical functions for manipulating the incident light to achieve different light intensity / field distributions on the image sensor. The switchable filter can be switched to selectively transmit light with different properties (e.g., polarization state or wavelength) to the image sensor. A liquid crystal device is an example of a switchable filter, which can be used to select the polarization state of the light transmitted to the system or image sensor or act as a wavelength filter. The switchable filter can be used to further improve the selectivity of light properties and reduce crosstalk between light with different properties in the optical system. In some cases, the switchable filter can further produce optical outputs at two locations. For example, light with a first property is transmitted by the filter to form a first image at a first location, and light with a second property is reflected to form a second image at a second location. Switchable filters are examples of active filters because they can be physically reconfigured under external control (e.g., rotated from a first orientation to a second orientation) to perform two different optical functions. The sensing / imaging system may further include a light emitter for actively illuminating the scene to be imaged by the system. For example, an image sensor may include a light emitter that illuminates the scene with light of different polarizations by switching between different light emitters or switching polarization filters between different polarization states. In another example, the sensing system may include a light emitter that illuminates the scene with light of different wavelengths by switching between different light emitters or switching between spectral filters that allow different emission wavelengths from a common light emitter to pass through. The light emitter may also be configured to emit structured light patterns to illuminate the scene.

[0064] Parfocal zoom lens

[0065] Figure 6 A parfocal zoom lens 600 is shown, which has a multiplexed metasurface architecture (a parfocal zoom lens is a zoom lens that maintains focus when its magnification / focal length changes). The parfocal zoom lens 600 may include: a first (incident) metasurface MS-1 having elementary atoms 200 formed on a first surface of a first substrate 610; and a second (outcryogenic) metasurface MS-2 having elementary atoms 200 formed on a second surface of the same substrate or on a second substrate 620, such as... Figure 6 As shown in the diagram. If the metasurface is on a separate substrate, the substrate can be separated by an air gap 630 or another substrate. Alternatively, the metasurface can be on the outer surface and / or inner (facing) surface of the substrate.

[0066] At least one of the metasurfaces of the parfocal zoom lens contains elementary atoms 200 that operate in at least two modes, each affecting the incident light in different ways depending on the properties of the incident light (e.g., polarization, wavelength, angle of incidence, etc.). The optical functions of the first and second metasurfaces can be accessed independently by switching, stepping, or sweeping the polarization, wavelength, angle of incidence, or other properties of the incident light. For example, the first metasurface MS-1 can act as a converging lens for vertically polarized light and a diverging lens for horizontally polarized light, while the second metasurface MS-2 can act as a converging lens for both horizontally and vertically polarized light. Independently controllable changes to the focusing characteristics of the two metasurfaces can provide optical zoom at a fixed track length of the optical system. (Either one or both metasurfaces can be sensitive to changes in the polarization or wavelength of the incident light.) Therefore, changes in optical magnification can be achieved without moving one substrate 610 relative to the other substrate 620 or without moving one metasurface MS-1 relative to the other metasurface MS-2. Next, a parfocal zoom lens can be implemented in a highly compact package (e.g., having a shape factor of less than 10 cubic centimeters or less than 1 cubic centimeter).

[0067] Active or passive beamsplitters or filters can be used in conjunction with multifunctional metasurfaces. In one embodiment, a beamsplitter (e.g., a polarizing beamsplitter or a dichroic mirror) can be added to split and direct light with different properties (e.g., different polarization states or wavelengths) to different detector arrays. Thus, different images generated by the multifunctional metasurface can be captured simultaneously or sequentially by different detector arrays based on the properties of the light. Simultaneous image capture can be achieved by using light with 45-degree, elliptical, or circular polarization, where the beamsplitter or filter divides the horizontal and vertical polarization components onto two different optical paths. In some cases, the metasurface or multifunctional metasurface can divide the horizontal and vertical polarization components onto two different optical paths. In some embodiments, a pixelated filter array with different filtering properties can be integrated onto the image sensor pixel array. Thus, different images generated by the multifunctional lens can be captured by different detector pixels based on the different properties of the light (e.g., polarization state, wavelength, etc.).

[0068] The parfocal zoom lens 600 may be included in an optical system that includes an optical device 660 located at the image plane of the zoom lens 600. When the zoom lens 600 is used to image a scene, the optical device may be an image sensor (e.g., a CMOS or CCD imaging array). In other embodiments further described below, when the zoom lens 600 is used to project an image, the optical device 660 may be a transmitter array or a microdisplay.

[0069] In addition to passive imaging / sensing, the parfocal zoom lens 600 of the present invention can be further operated in an active illumination mode by including a light emitter 650. For example, the parfocal zoom lens 600 can be used in conjunction with a light emitter 650, which illuminates a scene with light of different polarizations by switching between different light emitters or polarization filters. A liquid crystal device can also be used to tune the polarization state of light or act as a wavelength filter. In another example, the parfocal zoom lens 600 can be used in conjunction with a light emitter 650, which illuminates a scene with light of different wavelengths by switching between different light emitters or spectral filters. Structured light patterns can also be used to illuminate the scene.

[0070] In some implementations, the metasurface MS-1 of the parfocal zoom lens or other lens can be configured to selectively allow or prevent regions of the metasurface (e.g., Figure 6 The metasurface MS-1 in the image transmits incident light in a specific state (e.g., polarization state, wavelength, AOI, incident position, etc.) in region 1 to achieve a variable aperture. For example, light enters one or more selected regions (e.g., regions 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 ... Figure 6 The horizontally polarized light (from the outer region 2 of MS-1 in the middle) Figure 6 The light (indicated by the solid line in the diagram) can be deflected and trapped within the first substrate via total internal reflection as shown, while vertically polarized light (indicated by the dashed line) propagates through the same region and is reshaped. Some regions of metasurface MS-1 or any metasurface can also be designed to absorb, reflect, or otherwise block or attenuate incident light. In some cases, a region on the first metasurface of the meta-optics (e.g., region 2 on metasurface MS-1) can deflect light at a first wavelength, polarization, or angle of incidence to a region on a subsequent surface, in which the deflected light will be reflected, blocked, or otherwise prevented from participating in image formation, patterning, or optical sensing performed by the meta-optics or optical system, while light at a second wavelength, polarization, or angle of incidence may not be deflected by the first region and can participate in image formation, patterning, or optical sensing.

[0071] Figure 7A and Figure 7B An exemplary configuration of a parfocal zoom lens 600 is depicted, which can provide at least 10x optical zoom and can be used in a manner similar to... Figure 6The structure shown is implemented using the configuration described. In some cases, according to the described implementation, optical zoom from 5X to 50X can be achieved using a parfocal zoom lens utilizing atomic atoms on two metasurfaces. For the illustrated example operating at a wavelength of 670 nm, polarization-multiplexed metasurfaces MS-1 and MS-2 can be used, wherein the atomic atoms are formed of amorphous silicon and the substrate is formed of silicon dioxide. Imaging at other wavelengths is possible by selecting different materials and / or scaling the size and spacing of the atomic atoms. The space between multiple surfaces in the optical system (including optical component surfaces, window surfaces, and image sensor surfaces, etc.) can be filled with air or another medium (e.g., epoxy resin, glass / polymer spacers, etc.).

[0072] Figure 7A and Figure 7B The parfocal zoom lens 600 has an incident pupil diameter that can be controllably adjusted from 0.8 mm to 1.6 mm, but other values ​​are also possible. The fixed track length from the first metasurface to the image plane is approximately 4.82 mm. The back focal length is approximately 2.46 mm. The field of view can vary from 40° to 4° between two polarization states while achieving near-diffraction-limited imaging performance. Switching between horizontal and vertical polarization states changes the effective focal length of the parfocal zoom lens 600 by a factor of approximately 10X. The effective aperture of the parfocal zoom lens can be varied between two or more sizes by configuring two or more regions of the metasurface (e.g., MS-1) to have different responses to incident light with different properties (e.g., polarization, wavelength, incident angle properties). For example, a portion or region of the meta-atomic array (e.g., Figure 6 Zone 2) can be configured to internally reflect light with a first polarization and transmit light with a second polarization, thereby altering the zone's transmittance and the effective aperture size of the parfocal zoom lens. Figure 6 In the illustrated example, light with a first polarization is coupled into the first substrate at an angle less than the critical angle of the first substrate 610. In another example, a portion of the atomic array selectively redirects a portion of the incident beam in one direction relative to a phase assigned to a second polarization or wavelength, such that the effective aperture size of the optical system can vary between two values. More generally, the spectral, angular, and / or spatial response of a portion of the atomic array can be designed to selectively modulate, transmit, or block a portion of the beam incident on the atomic array, respectively, based on the wavelength, AOI, and incident position of the incident beam, to achieve multiple optical functions of the atomic optics (e.g., the parfocal zoom lens mentioned above). Selective modulation (e.g., beam redirection), transmission, or blocking can be switched between two or more states.

[0073] Zoom optical sensing / imaging systems can include zoom element optics (such as...) Figure 6 and Figure 7A The system comprises zoom element optics, switchable filters, and an image sensor. Depending on the properties of light, the element optics can provide different optical functions for manipulating incident light to achieve variable magnification or light intensity / field distribution on the image sensor located at the imaging plane of the optical system. Switchable filters can be switched to selectively transmit light with properties selected from different attributes (e.g., polarization states selected from different polarization states or wavelengths selected from different wavelengths) to the image sensor. Liquid crystal modulators can also be used to tune the polarization state of light or act as wavelength filters. The optical sensing / imaging system can further include a light emitter for active illumination. For example, the sensing / imaging system can include a light emitter that illuminates a scene with light of different polarizations by switching different light emitters or polarization filters (e.g., tunable liquid crystal waveplates or filters). In another example, the sensing / imaging system can include a light emitter that illuminates a scene with light of different wavelengths by switching different light emitters or spectral filters. Structured light patterns can also be utilized.

[0074] Figure 6 or Figure 7A When used in reverse with an image sensor replaced by a light emitter array (e.g., VCSEL, micro-LED, etc.) or a microdisplay, a parfocal zoom lens can easily achieve high-quality image / pattern projection with variable magnification or projection with varied patterned light intensity / field distribution. A reconfigurable optical projector system can include at least one zoom element optical lens, light emitter array, or microdisplay as described above, and optionally a switchable filter. Depending on the properties of the light, the element optics provide different optical functions to modulate the light to achieve variable magnification or light intensity / field distribution of the light emitted by the reconfigurable optical projector system. When needed, the switchable filter can be switched to selectively transmit light with different properties (e.g., polarization state or wavelength) emitted by the light emitter array. For example, the optical projector system can include a light emitter array or microdisplay that projects images with light of different polarizations by switching different light emitters or polarization filters. Liquid crystal devices can also be used to adjust or select the polarization state of light or act as wavelength filters. In another example, an optical projector system can include an array of light emitters or a microdisplay that projects images using light of different wavelengths by switching between different light emitters or spectral filters. Structured light patterns can also be projected.

[0075] In addition to the optical functionalities described above for optical devices, one, two, or more metasurfaces can be used to achieve additional optical functionalities. For example, an added metasurface can be used for beam steering in distance sensing element optics or parfocal zoom lenses, allowing for sweeping and imaging of a larger field of view compared to the absence of beam steering. In some implementations, different optical functions can be combined within a single metasurface. For instance, one half of the element atoms on the metasurface can be designed to provide a first optical function, and another half can be designed to provide a second optical function. The two halves of the element atoms can overlap and disperse across the metasurface, or be separated into different spatial regions or unit cells. According to one example, element atoms for imaging functionalities (e.g., distance sensing or parfocal zoom lenses) can be combined with element atoms for beam steering, each element atom having two or more selectable states based on different properties of the incident light. Other optical functions can be implemented besides zoom, beam steering, or computational imaging functions (e.g., distance sensing or pattern generation). Generally, depending on the properties of the incident light, meta-optical devices (comprising one, two, or more metasurfaces) can be configured to provide different optical functions to produce variable light intensity / field distributions. Therefore, reconfigurable optical sensing, imaging, and / or image projection based on light properties such as polarization, OAM, wavelength, and AOI can be realized.

[0076] Figure 8 An example of an optical system 800 is depicted, comprising a multifunctional meta-optical element 100 and a switchable filter 810. The meta-optical element 100 may be arranged to examine a scene or object 802. The optical system 800 may be configured to form an image onto an image plane 820, which may be flat (as depicted) or curved. At least one optical device 660 may be located at the image plane to record an image (e.g., an image sensor) or project an image (e.g., an image projector). Some systems may include a light source 805 (e.g., an emitter array) to generate light having more than one optical property (e.g., different polarization states, different wavelengths, different OAM). The described system may further include at least one image sensor and / or projector. Generally, the reconfigurable multifunctional optical sensing, imaging, and / or projection system described herein may include at least one meta-optical element and a switchable filter (optional for optical illumination or projection). Depending on the properties of light, for example, meta-optics (which may contain one, two or more metasurfaces) can provide different optical functions to manipulate light incident on the meta-optics and realize variable light intensity / field distribution on image sensors or variable light intensity / field distribution emitted by light sources or microdisplays.

[0077] Multifunctional optical elements can be implemented and / or included in optical systems in various configurations. Exemplary configurations are listed below. Corresponding methods for using the optical elements and operating the optical system can also be implemented.

[0078] (1) An optical device comprising: a substrate; and a metasurface comprising a plurality of elementary atoms disposed on a first side of the substrate and configured to impart a depth-sensitive phase profile to a first incident light in a first state and to impart a depth-insensitive phase profile to a second incident light in a second state different from the first state.

[0079] (2) The optical device according to configuration 1, wherein the depth-sensitive phase profile is characterized by two focal points whose positions vary with depth, and the depth-insensitive phase profile includes a cubic phase profile.

[0080] (3) The optical device according to configuration 1 or 2, wherein the first state is a first polarization state and the second state is a second polarization state.

[0081] (4) The optical device according to configuration 1 or 2, wherein the first state is a first wavelength state and the second state is a second wavelength state.

[0082] (5) The optical device according to any one of configurations 1 to 4 further comprises:

[0083] A second metasurface is disposed on a second side of the substrate opposite to the first side of the substrate and configured to form an image on an image plane of a scene viewed by the optical device.

[0084] (6) The optical device according to configuration 5, wherein the image plane is flat.

[0085] (7) The optical device according to configuration 6, wherein the second metasurface is configured to guide the first incident light and the second incident light to the image plane.

[0086] (8) An optical sensing system comprising:

[0087] The optical device according to any one of configurations 1 to 7;

[0088] A filter that communicates optically with the optical device;

[0089] A first image sensor, which is in optical communication with the filter to receive the first incident light in the first state and not receive the second incident light in the second state; and

[0090] A second image sensor is optically in communication with the filter to receive the first incident light in the second state and not receive the first incident light in the first state.

[0091] (9) An optical sensing system comprising:

[0092] The optical device according to any one of configurations 1 to 7;

[0093] A switchable filter that optically communicates with the optical device; and

[0094] An image sensor that communicates optically with the optical device.

[0095] (10) The optical sensing system according to configuration 9, wherein the switchable filter transmits first light having a first polarization state and suppresses the transmission of second light having a second polarization state in the first configuration, and transmits second light having the second polarization state and suppresses the transmission of first light having the first polarization state in the second configuration.

[0096] (11) The optical sensing system according to configuration 9, wherein the switchable filter transmits first light with a first wavelength and suppresses the transmission of second light with a second wavelength in the first configuration, and transmits second light with the second wavelength and suppresses the transmission of first light with the first wavelength in the second configuration.

[0097] (12) The optical sensing system according to any one of configurations 1 to 11 further comprises:

[0098] A light emitter configured to illuminate a scene examined by the optical device with light of different polarizations.

[0099] (13) The optical sensing system according to any one of configurations 1 to 11 further comprises:

[0100] A light emitter configured to illuminate a scene examined by the optical device with light of different wavelengths.

[0101] (14) A multifunctional optical device comprising: a first transparent substrate; a second transparent substrate spaced apart from the first transparent substrate; a first metasurface including a first plurality of elementary atoms disposed on a first surface of the first transparent substrate; and a second metasurface including a second plurality of elementary atoms disposed on a second surface of the second transparent substrate, wherein the first metasurface and the second metasurface are configured to focus first incident light in a first state onto an image plane at a first magnification or to perform a first optical function, and to focus second incident light in a second state different from the first state onto the image plane at a second magnification different from the first magnification or to perform a second optical function different from the first optical function, and wherein the relative positions of the first transparent substrate, the second transparent substrate and the image plane remain unchanged when the first incident light in the first state and the second incident light in the second state are focused.

[0102] (15) According to the multifunctional optical device of configuration 14, wherein the first metasurface is configured to converge the first incident light in the first state and diverge the second incident light in the second state, and the second metasurface is configured to converge the first incident light in the first state and converge the second incident light in the second state, such that the multifunctional optical device acts as a parfocal zoom lens.

[0103] (16) The multifunctional optical device according to configuration 14, wherein the first metasurface defines: a first region configured to transmit the first incident light in the first state and the second incident light in the second state; and a second region configured to transmit the first incident light in the first state and block, absorb, reflect and / or deflect the second incident light in the second state.

[0104] (17) The multifunctional optical device according to configuration 14, wherein the first metasurface defines: a first region configured to transmit the first incident light in the first state and the second incident light in the second state; and a second region configured to transmit the first incident light in the first state and couple the second incident light in the second state to the first transparent substrate at an angle less than the critical angle of the first transparent substrate.

[0105] (18) A multifunctional optical device comprising: a transparent substrate; a first metasurface including a first plurality of elementary atoms disposed on a first surface of the transparent substrate; and a second metasurface including a second plurality of elementary atoms disposed on a second surface of the transparent substrate or disposed on a second surface of a second transparent substrate, wherein the first metasurface and the second metasurface are configured to perform a first optical function for first incident light in a first state and a second optical function for second incident light in a second state different from the first state, wherein the first optical function includes distance sensing, projecting an image, or projecting a pattern of the first incident light.

[0106] (19) According to the multifunctional optical device of configuration 18, wherein the first metasurface is configured to converge the first incident light in the first state and diverge the second incident light in the second state, and the second metasurface is configured to converge the first incident light in the first state and converge the second incident light in the second state, such that the multifunctional optical device acts as a parfocal zoom lens.

[0107] (20) The multifunctional optical device according to configuration 18, wherein the first metasurface defines: a first region configured to transmit the first incident light in the first state and the second incident light in the second state; and a second region configured to transmit the first incident light in the first state and block, absorb, reflect and / or deflect the second incident light in the second state.

[0108] (21) The multifunctional optical device according to configuration 18, wherein the first metasurface defines: a first region configured to transmit the first incident light in the first state and the second incident light in the second state; and a second region configured to transmit the first incident light in the first state and couple the second incident light in the second state to the region of the second metasurface, the region being configured to block, absorb, reflect and / or deflect the second incident light.

[0109] (22) An optical sensing / imaging system comprising: a multifunctional optical device according to any one of configurations 18 to 21; a switchable filter in optical communication with the multifunctional optical device; and an image sensor in optical communication with the multifunctional optical device, wherein the switchable filter transmits first incident light having a first polarization state, a first wavelength, or a first orbital angular momentum in a first configuration, and transmits second incident light having a second polarization state, a second wavelength, or a second orbital angular momentum in a second configuration.

[0110] (23) The optical sensing / imaging system according to any one of configurations 18 to 22 further includes a light emitter configured to illuminate the scene examined by the multifunctional optical device with light having different wavelengths, different polarization states or different orbital angular momentum.

[0111] (24) An optical projection system comprising: a multifunctional optical device according to any one of configurations 18 to 21; a switchable filter in optical communication with the multifunctional optical device; and a light emitter array in optical communication with the multifunctional optical device, wherein the switchable filter is configured to selectively transmit a first incident light having a polarization state selected from different polarization states, a wavelength selected from different wavelengths, or an orbital angular momentum selected from different orbital angular momentum.

[0112] (25) The optical projection system according to configuration 24, wherein the light emitter array is a microdisplay.

[0113] Summarize

[0114] Although embodiments of the invention have been described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures for performing the functions described herein and / or obtaining these results and / or one or more of these advantages, and each of such variations and / or modifications is considered within the scope of the embodiments of the invention described herein. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on one or more specific applications in which the teachings of the invention are applied. Those skilled in the art will recognize or be able to determine many equivalents of the specific embodiments of the invention described herein using only conventional experimentation. Therefore, it should be understood that the foregoing embodiments are presented by way of example only, and that embodiments of the invention may be practiced in ways different from those specifically described and claimed within the scope of the appended claims and their equivalents. The inventive embodiments of this disclosure relate to each individual feature, system, article, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials, toolkits and / or methods that does not contradict each other is included within the scope of this invention disclosure.

[0115] Furthermore, various inventive concepts can be embodied in one or more methods, examples of which have been provided. Actions performed as part of said method can be ordered in any suitable manner. Therefore, embodiments can be constructed in which actions are performed in a different order than those shown, and these actions can include the simultaneous performance of several actions, even if the actions are shown as consecutive actions in the illustrative embodiments.

[0116] All definitions defined and used in this document should be understood as controls over dictionary definitions, definitions incorporated by reference in other documents, and / or the general meaning of the definition terms.

[0117] Unless otherwise expressly stated otherwise, the indefinite articles “a” and “an” as used herein in the specification and claims shall be understood to mean “at least one (type)”.

[0118] As used herein in the specification and claims, the phrase “and / or” should be understood to mean “any one or both” of the elements so combined, i.e., elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” should be understood in the same way, i.e., “one or more” of the elements so combined. Other elements may optionally be present, whether related to or unrelated to those specifically identified by the “and / or” clause. Thus, as a non-limiting example, in one embodiment, when used in conjunction with open-ended language such as “comprising,” a reference to “A and / or B” may refer only to A (optionally including elements other than B); in another embodiment, only to B (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); and so on.

[0119] As used herein in this specification and claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when items in a list are separated, “or” or “and / or” should be interpreted as inclusive, i.e., including a plurality of elements or at least one element in a list of elements, but also including more than one element and optionally other items not listed. Terms that clearly indicate the opposite, such as “only one of…” or “exact one of…” or, when used in claims, “consisting of…” will refer to including a plurality of elements or exactly one element in a list of elements. Generally, when preceded by an exclusive term such as “any one,” “one of…,” “only one of…,” or “exact one of…,” the term “or” as used herein should be interpreted only as indicating an exclusive alternative (i.e., “one or another, not two”). When used in claims, “consisting substantially of…” should have the ordinary meaning as used in the field of patent law.

[0120] As used herein in the specification and claims, the phrase "at least one" relating to a list having one or more elements should be understood to mean at least one element selected from any one or more elements in the element list, but not necessarily including at least one of every element specifically listed in the element list, and does not exclude any combination of elements in the element list. This definition also allows for the optional presence of elements other than those specifically identified in the element list referred to by the phrase "at least one," whether or not they are related to those specifically identified elements. Thus, as a non-limiting example, in one embodiment, "at least one of A and B" (or equivalently, "at least one of A or B," or equivalently, "at least one of A and / or B") may mean at least one element that optionally includes more than one A, has no B (and optionally includes elements other than B); in another embodiment, it may mean at least one element that optionally includes more than one B, has no A (and optionally includes elements other than A); in yet another embodiment, it may mean at least one element that optionally includes more than one A, and at least one element that optionally includes more than one B (and optionally includes other elements); and so on.

[0121] In the claims and the foregoing description, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “accommodating,” “constituting,” “made of,” etc., should be understood as open-ended, meaning that they include but are not limited to. As described in Section 2111.03 of the Patent Examination Manual of the United States Patent and Trademark Office, only the transitional phrases “composed of” and “substantially composed of” should be closed or semi-closed transitional phrases, respectively.

Claims

1. An optical imaging system, comprising: Substrate; A metasurface comprising a plurality of elementary atoms disposed on a first side of the substrate and configured to impart a depth-sensitive phase profile to a first incident light in a first state and a depth-insensitive phase profile to a second incident light in a second state different from the first state, wherein the plurality of elementary atoms comprise microfabricated structures that are separated from each other and disposed in a two-dimensional array on the first side of the substrate. Imaging sensor pixel array; as well as A pixelated filter array with different filtering properties is integrated on the imaging sensor pixel array, such that an image generated by the metasurface corresponding to the first incident light in the first state and the second incident light in the second state can be captured by different sensor pixels of the imaging sensor pixel array.

2. The optical imaging system of claim 1, wherein the depth-sensitive phase profile is characterized by two focal points whose positions vary with depth, and the depth-insensitive phase profile comprises a cubic phase profile.

3. The optical imaging system according to claim 1, wherein the first state is a first polarization state and the second state is a second polarization state.

4. The optical imaging system according to claim 1, wherein the first state is a first wavelength state and the second state is a second wavelength state.

5. The optical imaging system according to claim 1, further comprising: A second metasurface is disposed on a second side of the substrate opposite to the first side of the substrate and configured to form an image of the scene viewed by the optical imaging system on an image plane at one of the imaging sensor pixel arrays.

6. The optical imaging system of claim 5, wherein the image plane is flat.

7. The optical imaging system of claim 6, wherein the second metasurface is configured to guide the first incident light and the second incident light onto the image plane.

8. The optical imaging system according to claim 1, further comprising: A beam splitter that communicates optically with the metasurface, wherein: The first imaging sensor pixel array of the imaging sensor pixel array is optically in communication with the beam splitter to receive the first incident light in the first state and not receive the second incident light in the second state; and The second imaging sensor pixel array of the imaging sensor pixel array is optically communicated with the beam splitter to receive the second incident light in the second state and not receive the first incident light in the first state.

9. The optical imaging system according to claim 1, further comprising: A switchable filter that communicates optically with the metasurface.

10. The optical imaging system of claim 9, wherein the switchable filter transmits the first incident light having a first polarization state and suppresses the transmission of the second incident light having a second polarization state in a first configuration, and transmits the second incident light having the second polarization state and suppresses the transmission of the first incident light having the first polarization state in a second configuration.

11. The optical imaging system of claim 9, wherein the switchable filter transmits the first incident light having a first wavelength and suppresses the transmission of the second incident light having a second wavelength in a first configuration, and transmits the second incident light having the second wavelength and suppresses the transmission of the first incident light having the first wavelength in a second configuration.

12. The optical imaging system according to claim 9, further comprising: A light emitter configured to illuminate the scene being examined by the optical imaging system with light of different polarizations.

13. The optical imaging system according to claim 9, further comprising: A light emitter configured to illuminate the scene being examined by the optical imaging system with light of different wavelengths.

Images