Tunable liquid crystal metasurface

Abstract

Tunable optical metasurfaces can include an optically reflective surface to reflect optical radiation, such as infrared laser light. An array of optical resonant antennas can extend from or otherwise be positioned on the reflective surface, for example, at sub-wavelength spacing, e.g., less than half a wavelength. Voltage-controlled liquid crystals can be positioned in the optical field region of each optical resonant antenna. A controller can apply a voltage differential bias pattern to the liquid crystals of the optical resonant antennas, which can be arranged in a tiled, staggered, or randomly arranged subset of optical resonant antennas to obtain one-dimensional beam control, two-dimensional beam control, and / or spatial beam shaping.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Patent Application No. 16 / 357,288, filed March 18, 2019, entitled “TUNABLE LIQUID CRYSTAL METASURFACES”, and U.S. Patent Application No. 16 / 505,687, filed July 8, 2019, both of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to optical resonators and antennas. More specifically, this disclosure relates to tunable metasurfaces. Attached Figure Description

[0004] Figure 1A An illustration of a tunable optical metasurface according to one embodiment is shown.

[0005] Figure 1B It shows the incident angle at which the light is incident on Figure 1A Light radiation on the metasurface.

[0006] Figure 1C The applied voltage difference bias mode is shown, which is used to steer the reflected light radiation at a first steering angle.

[0007] Figure 1D The light radiation is shown as reflected at a first turning angle with respect to the incident angle of less than 90 degrees.

[0008] Figure 2A An example of a solid-state LiDAR system according to one implementation is shown.

[0009] Figure 2B It shows a beam with one-dimensional steering. Figure 2A Transmitting and receiving metasurfaces for solid-state LiDAR systems.

[0010] Figure 2C A top view of an exemplary optical path of a solid-state LiDAR system is shown.

[0011] Figure 2D A side view of the optical path of a solid-state LiDAR system according to one embodiment is shown.

[0012] Figure 3 An example of an optical reflective surface according to one embodiment is shown, which has a liquid crystal-covered metal track extending therefrom.

[0013] Figure 4AAn optically reflective copper surface according to one embodiment is shown, the optically reflective copper surface being covered with an insulating layer and extending therefrom a metal track having liquid crystal therebetween.

[0014] Figure 4B An optically reflective copper surface according to yet another embodiment is shown, the optically reflective copper surface being covered with an insulating layer and extending therefrom a metal track in which a liquid crystal layer is applied.

[0015] Figure 4C The light field region associated with an adjacent metal track extending from the optically reflective copper surface is shown according to one embodiment.

[0016] Figure 5 The voltage-controlled refractive index and corresponding reflection phase of a liquid crystal according to one embodiment are shown.

[0017] Figure 6 A simulation of the redirection and reflection of a light beam radiating at a negative 10-degree reflection angle according to one embodiment is shown.

[0018] Figure 7A A first voltage mode according to one embodiment is shown, which is applied to a one-dimensional array of metal tracks to generate a reflected beam at a first steering angle.

[0019] Figure 7B A second voltage mode according to one embodiment is shown, which is applied to a one-dimensional array of metal tracks to generate a reflected beam at a second steering angle.

[0020] Figure 7C A third voltage mode according to one embodiment is shown, which is applied to a one-dimensional array of metal tracks to generate a reflected beam at a third steering angle.

[0021] Figure 7D A fourth voltage mode according to one embodiment is shown, which is applied to a one-dimensional array of metal tracks to generate a reflected beam at a fourth steering angle.

[0022] Figure 8 A block diagram of an array of optical resonant antenna tracks subdivided into track subsets according to one embodiment is shown, each track subset comprising X tracks having X corresponding voltage bonding pads.

[0023] Figure 9 An example of a packaged array of an optical resonant antenna that can be peripherally tuned via voltage contacts according to one embodiment is shown.

[0024] Figure 10 Exemplary one-dimensional scan images via a solid-state LiDAR system are shown according to various implementation schemes. Detailed Implementation

[0025] Tunable optical metasurfaces can be used for beam shaping, including three-dimensional beam shaping, two-dimensional beam steering, or one-dimensional beam steering. In various embodiments, the tunable optical metasurface may include an optical reflective surface. The optical reflective surface may be a metallic surface selected to reflect light radiation within a specific bandwidth. A large number of optical resonant antennas may be positioned on the reflective surface. The optical resonant antennas may have subwavelength characteristics and be arranged at subwavelength intervals. For example, individual optical resonant antennas and the spacing between them may be less than half the wavelength.

[0026] Liquid crystals can be positioned around an optical resonant antenna, as a layer on top of the antenna, and / or as part of the antenna. A digital or analog controller can selectively apply varying voltage differences across the liquid crystal within the optical field region of each optical resonant antenna. The voltage controller can apply a voltage difference bias mode, such as a blazed grating mode, to the metasurface to obtain a target beam steering angle.

[0027] One-dimensional voltage bias modes can be applied to liquid crystals within the optical field region of a one-dimensional optical resonant antenna array to achieve one-dimensional beam steering. Two-dimensional voltage bias modes can be applied to liquid crystals within the optical field region of a two-dimensional array of an optical resonant antenna to achieve two-dimensional beam steering and / or spatial beam shaping. One-dimensional beam steering, two-dimensional beam steering, and spatial beam shaping are generally referred to herein as "beam shaping."

[0028] Based on the reflective properties of optical reflective surfaces, unbiased optical resonant antennas, and unbiased liquid crystals, metasurfaces can possess default reflection angles or reflection modes. In various implementations, a biased liquid crystal alters the reflection phase of light radiation from adjacent associated optical resonant antennas. Each different voltage mode on the metasurface corresponds to a different reflection phase mode. For a one-dimensional array of optical resonant antennas, each different reflection phase mode corresponds to a different steering angle in a single dimension. For a two-dimensional array of optical resonant antennas, each different reflection phase mode can correspond to a different two-dimensional beam steering angle. Alternatively, each different reflection mode can be used to achieve a unique spatial beamform.

[0029] Various shapes, sizes, materials, and constructions can be utilized. For example, an optical resonant antenna can be formed as a metal track extending from an optical reflective surface. In some embodiments, a liquid crystal deposit can fill a portion of each channel between adjacent optical resonant antennas. In other embodiments, the liquid crystal can be formed as a layer on top of the optical resonant antenna filling the channels therebetween.

[0030] A voltage controller can apply a voltage pattern to a metal track to bias its associated liquid crystal to obtain a target reflection phase pattern. In embodiments where both the optical reflective surface and the optical resonant antenna are metal, a dielectric or other insulator can separate the metal surface and the optical resonant antenna. The voltage controller can be connected to the metal track via contacts around the metasurface or via insulating vias in the metal surface.

[0031] Copper is an example of a metal that is suitable and cost-effective for infrared bandwidth commonly used in optical detection and ranging or LiDAR (e.g., 905 nm LiDAR systems and 1550 nm LiDAR systems). Copper can also be used at a variety of other operating wavelengths, and alternative metals (e.g., gold, silver, aluminum, etc.) and various dielectrics and metal-coated dielectrics are known to have high reflectivity at a variety of wavelengths. It should be understood that, as is known in the art, some materials may be preferred for visible wavelengths, others may be more suitable for ultraviolet wavelengths, and still others may be more suitable for infrared wavelengths.

[0032] A concrete example of a tunable optical metasurface is a planar copper reflector coated with silicon dioxide. 10,000 to 100,000 copper tracks extend from the silicon dioxide-coated copper reflector. These copper tracks are subdivided into subsets. Each subset comprises 100 to 10,000 copper tracks. The tunable optical metasurface may include multiple electrical contacts equal to the number of copper tracks in each subset.

[0033] For example, each subset may include 1,000 orbitals, and the tunable optical metasurface may include 50 subsets of a total of 50,000 metallic orbitals. The tunable optical metasurface may include 1,000 electrical contacts. Each electrical contact may be connected to one orbital in each subset.

[0034] Liquid crystal deposited between metal tracks can be secured via an optically transparent cover (e.g., glass). Applying a voltage mode to 1,000 electrical contacts via a voltage controller results in a voltage differential bias mode applied to the liquid crystal, which alters its local reflection phase. A beam steering controller selects a voltage mode corresponding to the reflection phase mode of the target beam steering angle. By modifying the applied voltage, the incident light radiation can be steered in one direction. A similar implementation using pillars or struts instead of elongated metal tracks can be used to allow for two-dimensional beam steering or spatial beam shaping.

[0035] Various combinations of the above-described embodiments and features can be used to construct solid-state optical detection and ranging (LiDAR) transmitters, receivers, or transceiver systems. According to various embodiments, the transceiver system may include a first tunable optical reflective metasurface for transmitting light and a second tunable optical reflective metasurface for receiving light reflected from a distant object (reflected light). The distance to the distant object can be calculated by measuring the time of flight of the transmitted and reflected light. Each optical reflective metasurface includes an optical reflective surface (or reflective layered surface) with a subwavelength optical resonant antenna array (e.g., a two-dimensional or one-dimensional array). A voltage bias mode applied to the liquid crystal associated with the optical resonant antenna modifies its local reflection phase. A controller can selectively apply the voltage mode to obtain a target beam steering angle or beam profile.

[0036] LiDAR systems can utilize laser diode light sources for transmission, such as laser diodes that emit light radiation at standard wavelengths of 905 nm or 1550 nm. Various other wavelengths can be used with the systems and methods described herein, including visible, sub-infrared, and infrared wavelengths. LiDAR systems may include receivers to reflect reflected light radiation from a target steering angle or beam shape (e.g., corresponding to the transmission steering angle or beam shape) to a receiving sensor (e.g., an avalanche photodiode array).

[0037] It should be understood that the metasurface techniques described herein can be combined with or otherwise utilize prior advances in surface scattering antennas, such as those described in U.S. Patent Publication No. 2012 / 0194399, which is incorporated herein by reference in its entirety. Additional elements, applications, and features of surface scattering antennas characterized by a reference wave or feed wave are described in U.S. Patent Publications Nos. 2014 / 0266946, 2015 / 0318618, 2015 / 0318620, 2015 / 0380828, 2015 / 0162658, and 2015 / 0372389 (each of which is incorporated herein by reference in its entirety). Specific descriptions of optical resonant antenna configurations and characteristic dimensions are described in U.S. Patent Applications Nos. 15 / 900,676, 15,900,683, and 15 / 924,744 (each of which is incorporated herein by reference in its entirety).

[0038] In this disclosure, examples of transmission (or reception) implementation schemes are provided, and it is understood that mutual reception (or transmission) implementation schemes are also contemplated. Similarly, it should be understood that the system can operate as a transmitter only, as a receiver only, or as both a transmitter and a receiver, having a time-division multiplexed transmitter / receiver, and / or a first metasurface acting as a transmitter and a second metasurface acting as a receiver.

[0039] Many previous advances in surface-scattering antennas have focused on relatively low frequencies (e.g., microwave and radio frequency bands). The embodiments described here support optical bandwidth and are therefore suitable for LiDAR and other optical-based sensing systems. Specifically, the systems and methods described herein operate in the sub-infrared, mid-infrared, high-infrared, and / or visible frequency ranges (generally referred to herein as "optical"). Given the feature dimensions required for subwavelength optical resonant antennas and antenna spacing, the described metasurfaces can be fabricated using microlithography and / or nanolithography processes, such as those commonly used for fabricating complementary metal-oxide-semiconductor (CMOS) integrated circuits.

[0040] Some infrastructures that can be used with the embodiments disclosed herein are already available, such as general-purpose computers, computer programming tools and techniques, digital storage media, and communication links. Many of the systems, subsystems, modules, components, etc., described herein can be implemented as hardware, firmware, and / or software. The various systems, subsystems, modules, and components are described according to the functions they perform, given the wide range of possible implementations. For example, it can be understood that many existing programming languages, hardware devices, frequency bands, circuits, software platforms, network infrastructure, and / or data storage can be used individually or in combination to implement specific control functions.

[0041] It should also be understood that two or more of the elements, devices, systems, subsystems, components, modules, etc., described herein can be combined into a single element, device, system, subsystem, module, or component. Furthermore, many elements, devices, systems, subsystems, components, and modules can be replicated or further divided into discrete elements, devices, systems, subsystems, components, or modules to perform the subtasks described herein. Any embodiment described herein can be combined with any combination of other embodiments described herein. Various permutations and combinations of embodiments are contemplated to the extent that they are not contradictory.

[0042] As used herein, computing devices, systems, subsystems, modules, or controllers may include processors, such as microprocessors, microcontrollers, logic circuits, etc. Processors may include one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), programmable array logic (PALs), programmable logic arrays (PLAs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), or other customizable and / or programmable devices. Computing devices may also include machine-readable storage devices, such as non-volatile memory, static RAM, dynamic RAM, ROM, CD-ROM, magnetic disks, magnetic tapes, magnetic, optical, flash memory, or other machine-readable storage media. Various aspects of certain embodiments may be implemented or enhanced using hardware, software, firmware, or a combination thereof.

[0043] Components of some disclosed embodiments are described and illustrated in the figures herein to provide specific examples. Many of these components can be arranged and designed in a variety of different configurations. Furthermore, features, structures, and operations associated with one embodiment can be applied to or combined with features, structures, or operations described in conjunction with another embodiment. In many instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of this disclosure. The right to add any described embodiment or feature to any figure and / or as a new figure is expressly reserved.

[0044] The embodiments of the systems and methods provided in this disclosure are not intended to limit the scope of this disclosure, but only represent possible embodiments. Furthermore, the steps of a method do not necessarily need to be performed in any particular order, or even sequentially, nor do they need to be performed only once. As previously stated, the descriptions and variations concerning the transmitter are equally applicable to the receiver, and vice versa.

[0045] Figure 1A A diagram of a tunable optical metasurface 100 according to one embodiment is shown. In the illustrated embodiment, the optical metasurface includes an optical resonant antenna 150 configured as elongated tracks arranged in a one-dimensional array. Block diagram 150' provides a conceptual diagram of the optical resonant antenna 150 as a resonator tuned to a specific optical frequency or range of optical frequencies. The elongated tracks can be connected to a programmable logic controller, CPU, microcontroller, or other controller to selectively apply tuning signals to modify the resonance of the optical resonant antenna 150. Each control pin 120 can allow the tuning signal to control the resonance of one or more optical resonant antennas, as described in detail according to the various embodiments herein.

[0046] Figure 1B It shows the incident angle at which the light is incident on Figure 1A The light radiation 125 is incident on the metasurface 100. The incident angle shown is approximately 45 degrees. The incident light radiation is shown as being incident on the conceptual block diagram 150', but it should be understood that the light radiation would actually be incident on the optical resonant antenna 150 of the metasurface 100. However, the tuning fork shown in the conceptual block diagram 150' provides a visualization of the functionality of the metasurface 100.

[0047] Figure 1C An applied voltage difference bias pattern 175 is shown, which is applied to the tuning fork of functional block diagram 150' to redirect the reflection of incident light radiation 125 at a first steering angle. As shown, different voltage differences 175 can be applied to different tuning forks in conceptual block diagram 150'. In various embodiments, each tuning fork can represent multiple adjacent or non-adjacent optical resonant antennas. As previously described, each unique voltage difference bias pattern 175 can correspond to a different radiation pattern (e.g., beam steering, beam shape, amplitude, phase delay, etc.).

[0048] Figure ID shows light radiation 125, which is reflected at an acute angle as “reflected light radiation” 126 (i.e., the turning angle is shown as less than 90 degrees relative to the angle of incidence). Modifying the voltage 175 applied to the optical resonant antenna 150 changes the voltage difference affecting the associated liquid crystal. Each different voltage difference modifies the refractive index of the liquid crystal and corresponds to a different reflection phase. In the one-dimensional array of the elongated orbital optical resonant antenna 150, as shown, each different mode of reflection phase results in a different beam turning angle.

[0049] Figure 2A An example of a solid-state LiDAR system 200 according to one embodiment is shown. The housing 205 shown is merely an example, and any number of alternative shapes, sizes, styles, etc., are possible. At least one window portion 250 of the housing 205 may be optically transparent at the operating wavelength. In some embodiments, the window portion 250 may be uncovered to allow all light radiation to enter the housing 205. In other embodiments, the window portion 250 may include a filter to filter some or all electromagnetic radiation (and optionally, its harmonics) that is not within the operating bandwidth.

[0050] Figure 2B It shows a beam with one-dimensional steering. Figure 2A The solid-state LiDAR system 200 comprises a transmissive metasurface 210 and a receiving metasurface 215. A laser diode 206 (e.g., a 905 nm laser diode or a 1550 nm laser diode) illuminates the transmissive metasurface 210 via a collimating / focusing optics 204 having optical radiation (not shown for clarity). The optical radiation incident on the transmissive metasurface is reflected from the transmissive metasurface as transmitted optical radiation 226. A control circuit (e.g., a microchip 235) tunes the optical resonant antenna of the transmissive metasurface 210 by applying a voltage difference bias mode to the liquid crystal associated therewith to select a reflection phase mode corresponding to the target beam steering angle of the reflected optical radiation 226.

[0051] The control circuit 235 also tunes the optical resonant antenna of the receiving metasurface 215 by applying a corresponding voltage difference bias mode to select a reflection phase mode corresponding to the same target beam steering angle. Transmitted light radiation 226 bounces off a distant object and is received by the receiving metasurface 215 as bounced light radiation 227. The light radiation 227 received by the receiving metasurface 215 is reflected by the metasurface at the target beam steering angle to the receiving sensor 207. The receiving metasurface 215 can reflect the light radiation to the receiving sensor 207 via a spherical lens (not shown). The receiving sensor 207 can be a photodiode array, such as an array of avalanche photodiodes (APDs) or a single-photon avalanche diode (SPAD).

[0052] Figure 2C It shows Figure 2A and 2B A top view of an exemplary optical path of a solid-state LiDAR system 200. One or more light sources (e.g., an array of diodes 206 as shown) transmit light radiation through a collimating optics 204 to a transmissive metasurface 210. Specifically, light radiation from the array of diodes 206 is collimated by the collimating optics 204 to a transmission aperture region 211 on the transmissive metasurface 210.

[0053] Transmitted light radiation bounces off one or more distant objects and is received by the receiving metasurface 215 as the bounced light radiation. The light radiation is reflected by the receiving aperture region 216 of the receiving metasurface 215 and passes through the spherical lens 217 to be received by the receiving sensor 207. Figure 2C It also includes a graphical representation of the field of the transmitted beam relative to the entire field of view (FOV) provided by the optical path shown, as shown in Figure 201.

[0054] Figure 2D A side view of the optical path of a solid-state LiDAR system 200 according to one embodiment is shown. As previously described, one or more diodes (e.g., laser diode 206) generate light radiation 230 as collimated light radiation 228 that passes through collimating optics 204. The collimated light radiation is reflected by a transmissive metasurface 210 as transmitted light radiation 226. The transmitted light radiation bounces off one or more distant objects and returns as reflected light radiation 227. The reflected light radiation 227 is reflected by a receiving metasurface 215 as reflected light radiation 229 and refracted by a spherical lens 217. The refracted light radiation 231 is received by a receiving sensor 207.

[0055] Figure 3 An example of an optical reflective metasurface 300 having a reflective surface 301 (e.g., a metallic reflector or a dielectric reflector) is shown. The reflective surface 301 has an insulating layer 305 to provide electrical insulation from the metallic orbital optical resonant antenna 375. Each optical resonant antenna 375 has an electrically insulating layer 380. The electrically insulating layer 380 may also cover the top of each metallic orbital optical resonant antenna 375.

[0056] Figure 4AA specific embodiment of a tunable optical resonant antenna 401 extending from an optical reflective surface 410 is shown. Copper antenna tracks 430 extend perpendicularly from the optical reflective surface 410 but are electrically insulated from it by a layer of oxide or other dielectric material 420. An insulating layer 440 (e.g., silicon nitride or another electrically insulating layer) covers each copper antenna track 430. Liquid crystal 450 is deposited within the gaps between adjacent copper antenna tracks 430. A voltage controller 460 applies a voltage to the copper antenna tracks 430. The reflection phase associated with the liquid crystal 450 can be tuned based on the voltage difference between the copper antenna tracks 430 generated by the voltage controller 460.

[0057] Figure 4B Another example of a tunable optical resonant antenna 403 with exemplary dimensions according to one embodiment is shown. A voltage controller 461 is electrically contacted with a copper antenna track 430 via an insulating via in the optical reflective surface 410 and an oxide layer 420. A liquid crystal layer 452 covers an insulator 440 on the copper antenna track 430 and fills the gaps therebetween. The insulator 440 may include, for example, silicon nitride, oxide, or another electrical insulator.

[0058] Figure 4C A light field region 480 according to one embodiment is shown, which is associated with an adjacent metal track 430 extending from an oxide layer 420 on an optical reflective surface 410. An electric field applied by a voltage controller 460 tunes the optical resonant antenna 404 by modifying the refractive index of the liquid crystal applied on, around, or between the resonant metal track 430.

[0059] Figure 5 A graph 500 showing the voltage-controlled refractive index and corresponding reflection phase 510 of a liquid crystal 520 according to one embodiment is illustrated. Graph 500 shows that the reflection phase can vary significantly based on the refractive index 520 of the dielectric. As shown, phase modulation of nearly 2π radians (refractive index modulation of only 0.25) is possible. The liquid crystal is a suitable material that provides a variable refractive index 520 and corresponding reflection phase 510 based on a variable control voltage difference.

[0060] Figure 6 A simulation 600 of a beam-directing metasurface according to one embodiment is shown, wherein the light radiation is incident at -70 degrees and reflected at -10 degrees, both of which are measured relative to the normal vector of the metasurface.

[0061] Figure 7AA first voltage mode 790 is shown applied to a one-dimensional array of metal orbitals 700. A laser 710 generates incident light radiation 711 to irradiate a tunable metasurface having a one-dimensional array of metal orbitals 700. The metasurface can be tuned by applying high and low voltage modes 790 to reflect the incident light radiation 711 as a reflected beam 725 at a first turning angle of approximately -50°.

[0062] Figure 7B A second voltage mode 791 is shown, which is applied to a one-dimensional array of metal orbitals 700 to generate a reflected beam 726 at a second turning angle of approximately -30°.

[0063] Figure 7C A third voltage mode 792 according to one embodiment is shown, which is applied to a one-dimensional array of metal rails 700 to generate a reflected beam 727 with a third steering angle of approximately 5°.

[0064] Figure 7D A fourth voltage mode 793 according to one embodiment is shown, which is applied to a one-dimensional array of metal rails 700 to generate a reflected beam 728 at a fourth steering angle of approximately 40°.

[0065] In short, Figures 7A to 7D Various voltage modes are shown to obtain various target steering angles. It should be understood that in each illustrated embodiment, laser 710 can be replaced by a sensor array (e.g., APD or SPAD) to receive bounce radiation reflected from the receiving metasurface of metal track 700 at the target steering angle.

[0066] Figure 8 A block diagram 800 shows an array of optical resonant antenna tracks subdivided into X subsets 830 of tracks, each subset 830 having X corresponding voltage-bonded pads 805 on a chip. A routing bus 820 can route contacts 805 between the voltage-bonded pads and the array of metal track subsets 830. For example, 50,000 copper tracks can be subdivided into 50 subsets 830 of every 1,000 copper tracks. The tunable optical metasurface can include a number of electrical contacts 805 equal to the number of copper tracks in each subset 830. Each electrical contact can be connected to one track within each subset 830. Therefore, the reflection phase map of each copper track subset 830 can be the same as the reflection phase map of every other copper track subset 830.

[0067] The block diagram 800 of the tunable optical metasurface can be used for spatial beam shaping, two-dimensional beam steering, or one-dimensional beam steering, depending on the configuration of the orbits and the applied voltage mode. For example, a one-dimensional array of elongated orbits can be used for one-dimensional beam steering. A two-dimensional array of struts or multiple one-dimensional arrays of elongated orbits arranged in a two-dimensional array can be used for two-dimensional beam steering and / or spatial beam shaping.

[0068] As in previous implementations, subsets of optical tracks can extend from an optically reflective surface (such as copper). Liquid crystals can be positioned between the tracks, as a cover on each individual track, within the gaps between adjacent tracks, or as a layer covering the tracks and the gaps between them. Various shapes, sizes, materials, configurations, etc., can be utilized.

[0069] Figure 9 An example of a packaged chip 900 according to one embodiment is shown, which has an array of peripherally tunable optical resonant antennas via electrical contacts 932. Incident light radiation 925 from the laser diode is reflected as transmitted light radiation 926 at a target directional angle based on the voltage (e.g., voltage or current electrical contact) applied via the electrical contacts 932.

[0070] Figure 10 Exemplary one-dimensional scans via a solid-state LiDAR system 1000 according to various embodiments are shown. As illustrated, the solid-state LiDAR system 1000 can perform a one-dimensional scan along a horizontal field of view with a fixed vertical field of view. A transmissive metasurface transmits light radiation 1026 at a first horizontal angle (e.g., illustrated as 120°) and a fixed vertical viewing angle (e.g., illustrated as 25°). The transmitted light radiation 1026 bounces off a distant object represented by plane 1050, although it is recognized that the distant object may be at a different distance from the solid-state LiDAR system 1000 and not necessarily in the same plane.

[0071] Distant objects reflect light radiation as reflected light radiation 1027. A receiving metasurface receives the solid-state LiDAR system 1000 at corresponding horizontal and vertical field of view. In various embodiments, and as described herein, the solid-state LiDAR system can scan along the horizontal field of view at various scan angles by modifying the reflection phase modes of the transmitting and receiving metasurfaces during the scan time period.

[0072] In other embodiments, a LiDAR system may include a tunable transmissive metasurface for transmitting beam-shaped optical radiation according to any embodiment described herein. However, instead of using a tunable metasurface to receive reflected optical radiation, a LiDAR system may include a fixed-focus receiver, a receiver with limited tunability, and / or one or more omnidirectional receivers. In other embodiments, a LiDAR system may include a tunable receiving metasurface according to any embodiment described herein, but may include more conventional transmitters such as fixed-focus transmitters, limited-focus transmitters, or omnidirectional transmitters.

[0073] In other embodiments, the system may function solely as a transmitter and include a tunable metasurface for emitting light radiation, but without a corresponding receiver. Similarly, the system may function solely as a receiver and include a tunable metasurface for receiving light radiation, but without a corresponding transmitter.

[0074] In any of the various embodiments, the optical resonant antenna can be formed as elongated metal tracks for one-dimensional beam steering, as shown and described. In other embodiments, the columns and rows of struts can be used for two-dimensional beam shaping and / or spatial beam shaping. In embodiments for one-dimensional beam steering, each optical resonant antenna may include a first elongated metal track extending from an insulator having a defined width W and length L to a height H. The proportions of the metal tracks can be selected for a specific resonance within the operating wavelength. The elongated metal tracks may extend between the edges of the underlying reflective surface and may be substantially parallel to each other.

[0075] Similarly, in any of the various implementations, the optical resonant antenna may include a high-Q tunable resonant waveguide, such as a high-Q tunable resonant plasma waveguide. This high sensitivity to the refractive index of the dielectric is achieved by the high Q value of the resonance (e.g., Q >= 10). Any of a variety of mathematical models for beam steering can be used, including, for example, the Gerchberg-Saxton algorithm.

[0076] This disclosure has been made with reference to various exemplary embodiments, including the best mode. However, those skilled in the art will recognize that changes and modifications can be made to the exemplary embodiments without departing from the scope of this disclosure. While the principles of this disclosure have been shown in various embodiments, numerous modifications to the structure, arrangement, proportions, elements, materials, and components may be adapted to specific environmental and / or operational requirements without departing from the principles and scope of this disclosure. These and other changes or modifications are intended to be included within the scope of this disclosure.

[0077] This disclosure should be considered illustrative rather than restrictive, and all such modifications are intended to be included within its scope. Similarly, benefits, other advantages, and solutions to problems have been described above with respect to various embodiments. However, benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more apparent should not be construed as critical, essential, or fundamental features or elements. Therefore, it should be determined that this disclosure covers at least the following claims.

Claims

1. A solid-state optical detection and ranging (LiDAR) transceiver system, comprising: A tunable first optical reflective metasurface that reflects emitted light radiation within its operating bandwidth. The first optical reflective metasurface includes a first array of optical resonant antennas arranged at subwavelength intervals on a first reflective surface of a subset of N optical resonant antennas, where N is an integer. The liquid crystal is positioned in the light field region of the optical resonant antenna in the first array; A light source that emits light radiation within the operating bandwidth onto the first optical reflective metasurface; A voltage controller selectively applies N differential bias voltage differential bias patterns to the liquid crystal of each subset of the N optical resonant antennas in the first array of the optical resonant antennas to tune the emitted light radiation energy toward the target location. A second optical reflective metasurface, which can be tuned by the voltage controller to receive light radiation reflected from the target location. The second optical reflective metasurface includes a second array of optical resonant antennas arranged at subwavelength intervals on the second reflective surface, and The liquid crystal is positioned in the optical field region of the optical resonant antenna in the second array; as well as The sensor receives light radiation from the second optical reflective metasurface.

2. The transceiver system of claim 1, wherein the light source comprises a diode laser.

3. The transceiver system of claim 1, wherein the sensor comprises an array of avalanche photodiodes (APDs).

4. The transceiver system of claim 1, wherein the sensor comprises an array of single-photon avalanche diodes (SPADs).

5. The transceiver system of claim 1, wherein the voltage controller can tune the emitted light radiation toward a target location by modifying the phase of the reflected light radiation associated with each of the optical resonant antennas of the first array.

6. The transceiver system of claim 1, wherein the optical resonant antenna of each of the first array and the second array comprises metal tracks extending from respective first and second reflective surfaces, wherein the metal tracks are spaced apart from each other to form a channel therebetween.

7. The transceiver system of claim 1, wherein the first reflective surface and the second reflective surface include portions of a single reflective layer located below the optical resonant antenna.

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