Metasurface module and optical device

Abstract

A metasurface module and optical device are disclosed. The metasurface module includes a DBR layer and a metasurface layer disposed on the DBR layer. The metasurface layer includes multiple nanostructures arranged on the DBR layer. The multiple nanostructures are arranged in a preset configuration and configured to change the light modulation of light emitted from a light source and separate the light spectrum into multiple specific wavelength bands.

Description

[Technical Field]

[0001] This invention relates to the field of optical technology, specifically to a metasurface module, optical device, AR / VR / MR glasses, sensing (such as time-of-flight) and its spectral applications. [Previous Technology]

[0002] Stereoscopic 3D imaging typically uses glasses with two different complementary color bands or different polarizations. These methods are inexpensive and compatible with full-color displays and projectors. However, these technologies, especially stereoscopic ones, result in unsatisfactory 3D image rendering due to inaccurate color reproduction (color distortion) and retinal competition, which can lead to eye strain. To alleviate retinal competition, each eye should receive more color information. For current stereoscopic images (e.g., red-cyan, green-magenta, yellow-blue), one eye receives one primary color, while the other eye receives two primary color bands (e.g., cyan is a combination of blue and green).

[0003] Furthermore, crosstalk (also known as ghosting) hinders the brain's ability to fully capture true-color 3D images from two slightly different images perceived by each eye. Therefore, crosstalk signals entering red and blue pixels typically originate from green pixels, which leak the red and blue pixel spectra into the green region. Similarly, green pixels receive crosstalk signals from two red pixels and two blue pixels. Thus, an imperfect bandpass color filter causes color to leak from one channel to another, causing discomfort to the user. A metasurface module is disclosed here as a metasurface-based color filter that can be carefully tuned for the wavelengths of each color to avoid overlap.

[0004] Furthermore, each eye can see colors opposite to those of the other eye, and the degree of polarization is also different. The proposed metasurface module can support monochromatic or multicolor modulation, offering great design freedom and allowing precise adjustment of the wavelength for each color. Moreover, this example can be easily integrated into existing AR / VR / MR glasses, such as waveguides, pancakes, birdboxes, and freeform-based optical elements. Furthermore, the implementation of the proposed metasurface module is not limited to the applications mentioned above; it also has the potential for other applications, such as spectroscopy, sensing, time-of-flight (ToF), optical angular momentum (OAM) generators and classifiers, and superlenses.

[0005] Knowledge Technology

[0006] 1. Previous studies have investigated color filters with opposite colors (see Figure 1A), cross-polarized filters (see Figure 1B), and active shutter-based filters (see Figure 1C), such as liquid crystal glasses (not shown), as shown in Figures 1A-1D. As shown in Figure 1B, cross-polarized glasses are the most common type of glasses in 3D cinemas. However, these glasses are not the most demanding on the market due to the following fundamental challenges and issues: Color reproduction is generally poor.

[0007] 2. Discomfort during prolonged viewing (depth continuity issue).

[0008] 3. Ghosting can be reduced by removing a small amount of the opposite color from the source image, but this will result in poor color reproduction.

[0009] 4. However, when crosstalk is present, the color space mapping algorithm used to reproduce true colors cannot function.

[0010] Therefore, it is necessary to seamlessly control crosstalk by creating perfect color filters and to re-examine stereoscopic images as an example of high-level 3D image rendering. In addition, each eye should see more color bands with different polarizations to ensure that the left eye only sees the content of the left eye and the right eye only sees the content of the right eye. [Summary of the Invention]

[0011] In view of the above, it is necessary to provide a metasurface module and an optical device to solve the above problems.

[0012] One embodiment of this application provides a metasurface module, including a DBR layer and a metasurface layer disposed on the DBR layer. The metasurface layer includes a plurality of nanostructures arranged on the DBR layer. The plurality of nanostructures are arranged in a preset configuration and configured to change the light modulation of light emitted from the light source and separate the light spectrum into a plurality of specific bands.

[0013] An embodiment of this application provides an optical device, including: at least one emitting light source; and at least one metasurface module as described above, wherein the at least one metasurface module is used to receive light from the at least one emitting light source, and the at least one metasurface module is configured to reflect light onto a target object.

[0014] In the aforementioned metasurface module, crosstalk is seamlessly controlled by creating a better color filter, and stereoscopic images are re-examined as an example of high-level 3D image rendering. In addition, more color bands are allowed to be seen by each of the user's eyes with different polarizations to ensure that the left eye only sees the content of the left eye and the right eye only sees the content of the right eye.

Implementation Method

[0016] Embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0017] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "level," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, it should be noted that "multiple" means two or more, unless otherwise explicitly specified.

[0018] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0019] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower level than the second feature.

[0020] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure of this application, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit this application. In addition, reference digits and / or reference letters may be repeated in different examples of this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0021] Human stereoscopic vision can be stimulated by displaying two precisely processed images to each eye. Stereoscopic vision begins to function when the images seen by both eyes are similar in all properties, but the object's position is slightly horizontally shifted. However, any additional differences in intensity, color, timing, focus, or object shape can cause an unconscious overload on the visual system. Depending on the degree of this difference, users may experience a lack of immersion in 3D, leading to discomfort and headaches, or even a complete loss of depth perception. In recent years, in addition to 3D cinema applications, stereoscopic imaging has also been widely used in smart glasses.

[0022] AR / VR / MR glasses are rapidly developing, providing users with superior image quality that is unavailable on existing TVs or smartphones. However, to create a well-generated 3D object, the GPU needs to undertake heavy processing tasks, which quickly depletes the battery. For complex objects, it may not be fast enough to meet the requirements of real-time applications. Furthermore, camera-based glasses that capture and display 3D images only function when there is sufficient ambient light; otherwise, errors in creating 3D images can cause eye discomfort. Additionally, cross-polarization, filter wheels, active color filters, dichroic filters, dual complementary channel switching, and complementary color stereoscopic glasses used to generate 3D images are prone to crosstalk and unrealistic color reproduction due to defects in polarizers or color filters, leading to eye fatigue. A multi-band metasurface module is disclosed here, and the inter-band crosstalk generated by the metasurface module can be sufficiently adjusted. Specifically, a multi-band metasurface module is disclosed, and the inter-band crosstalk generated by the metasurface module can be sufficiently adjusted. Furthermore, each eye can receive image content with different polarizations, further ensuring that each eye only sees the image it wants to see, thereby minimizing crosstalk.

[0023] Once crosstalk is mitigated, the color matching algorithm in the CIELAB (CIELUV) color space will match the perceived color features, especially the hue, rather than mitigating the sum of the distances between the perceived stereo image colors and stereo image pairs.

[0024] The metasurface module 60 of this application can be applied to different platforms that include different displays. In this article, the term "display" can refer to laser beam scanners (LBS), micro light-emitting diodes (uLED), micro organic light-emitting diodes (uOLED), liquid-crystal-on-silicon (LCOS), digital micromirror devices (DMD), digital light processors (DLP), micro and pico projectors; and various couplers, such as freeform half-mirrors, bird's-bowl mirrors, pancake lenses, spherical lenses, freeform prisms, holographic optical elements (HOE), cascaded mirrors, grating couplers, surface relief gratings (SRG), volume Bragg gratings (VBG), polarization volume gratings (PVG), and holographic polymer-dispersed liquid crystals. Dispersed liquid crystal (HPDLC), hybrid curved holographic reflector (HCHR), pin-mirror, partial reflector, half-tone reflector, meta-waveguide, metasurface, metalens, or other diffractive elements.

[0025] The metasurface module 60 can also be used in spectroscopy and ToF applications because it can separate the spectrum of incident light into the required number of bands with ultra-fine precision.

[0026] Embodiments of the present disclosure will now be described with reference to the accompanying drawings and by way of example only. This application is merely exemplary, and changes to details may be made within the scope of the principles of this disclosure. Therefore, it should be understood that modifications may be made to the embodiments within the scope of the requested items.

[0027] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The technical terms used herein are intended to provide a thorough understanding of the embodiments described herein, but should not be construed as limiting the scope of the embodiments.

[0028] As shown in Figures 1A-1D, selected conventional techniques for 3D imaging are depicted, illustrating a display 10A and AR / VR / MR glasses 100. As shown in Figure 1A, Figure 1A illustrates a conventional technique for 3D imaging using color-filtered glasses 100 with arbitrary complementary color bands (e.g., red-cyan, green-violet, yellow-blue). Specifically, the complementary color bands used in the figure are shown. For example, Figure 1A could use cyan and red color bands. The display 10A projects an image with one complementary color band (e.g., cyan band) onto one eye and another image with another complementary color band (e.g., red band) onto the other eye, thus forming a 3D image for the user's brain.

[0029] As shown in Figure 1B, Figure 1B illustrates a conventional technique for 3D imaging using cross-polarized glasses (linear polarizers or circular polarizers). Taking 3D imaging using cross-polarized glasses with a circular polarizer (which can be integrated with display 10A) as an example, display 10A projects circular light to one eye and different circular light to the other eye to form a 3D image in the user's brain. It is understood that another embodiment using a linear polarizer can also be configured in a similar manner to the embodiment using a circular polarizer in Figure 1B.

[0030] As shown in Figure 1C, Figure 1C illustrates a conventional technique for 3D imaging using shutter glasses 100. The display 10A projects light with different polarizations to each eye, and the shutter glasses 100 switch between images at a rate faster than the human eye's detection rate (frames per second) to create the illusion of motion, thereby forming a 3D image in the user's brain.

[0031] As shown in Figure 1D, Figure 1D illustrates a preferred conventional technique in which a camera 13 captures surrounding objects (not shown), then reconstructs a 3D image based on the objects, and displays it to the user through the display 10B of the AR / VR / MR glasses 100. The display 10B can be integrated into the AR / VR / MR glasses 100.

[0032] As shown in Figures 2A-2C, one design includes two displays 10. However, another design is also possible, in which only one display 10 is located in the center, and the image can be sent to both eyes by means of a beam splitter (not shown in Figure 2A). As shown in Figure 2A, the portions marked "A1 and A2" can be used individually as metasurfaces, thereby enabling the separation of colors into specific bands with specified polarizations. The portions "B1 and B2" are couplers, which can employ SRG, VBG, PVG, HPDLC, HCHR, needle mirrors, partial reflectors, halftone reflectors, superwaveguides, metasurfaces, superlenses, and other diffractive or non-diffractive elements to guide the image to the user's eyes. In other embodiments, the portions marked "A1 and A2" can also be metasurface modules 60, as described below. PL1 and PL2 represent the polarization types of the light emitted from the left and right eyes, respectively, which can be linearly polarized light or circularly polarized light (or unpolarized light). The display 10 can be any of, but is not limited to, LSB, uLED, uOLED, LCOS, DMD, DLP, micro and micro projectors.

[0033] As shown in FIG2B, FIG2B illustrates the application of a metasurface module 60 according to another embodiment of the present application to a pancake-shaped glasses 100. PK numerically represents a pancake lens. Specifically, 2B1 and 2B2 in FIG2B illustrate the optical path of the eye in the embodiment of FIG2B. The display 10 (or light source) emits light to the metasurface module 60. The metasurface module 60 then reflects the light toward the pancake lens PK. Subsequently, the light passes through the pancake lens PK and enters the eye. The pancake-shaped glasses 100 can be VR glasses, in which the eye does not receive ambient light (see 2B1 in FIG2B). The pancake-shaped glasses 100 can also be AR glasses, in which the eye receives ambient light (see 2B2 in FIG2B).

[0034] As shown in FIG2C, FIG2C illustrates the application of a metasurface module 60 according to another embodiment of the present application to a freeform surface-based glasses 100. The freeform surface-based glasses 100 may use a freeform surface optical element FR. The freeform surface optical element FR may be a bird bath. Specifically, 2C1 and 2C2 in FIG2C illustrate the optical path of the eye in the embodiment of FIG2C. The display 10 (or light source) emits light to the metasurface module 60. The metasurface module 60 then reflects the light toward the freeform surface optical element FR. Subsequently, the light passing through the freeform surface optical element FR enters the eye. The freeform surface glasses 100 may be VR glasses, in which the eye does not receive ambient light (see 2C1 in FIG2C). The freeform surface glasses 100 may be AR glasses, in which the eye receives ambient light (see 2C2 in FIG2C).

[0035] Figure 3 shows a schematic diagram of VR / AR glasses (not shown) including a metasurface module 60. The figure shows a display 10, a lens group 20, a controller 50, and the metasurface module 60. The display 10 can be any of, but is not limited to, LSB, uLED, uOLED, LCOS, DMD, DLP, micro and micro-micro projectors. The display 10 projects an image, the lens group 20 collimates the light and directs it through an optional polarizer 11 (e.g., a linear polarizer or a circular polarizer, depending on the design of the nanostructure, whether they are polarizer-dependent or polarizer-independent), and then the light reaches the surface of the metasurface module 60 equipped with the controller 50. The controller 50 is configured to electrically or mechanically control the metasurface module 60. In some embodiments, the controller 50 is configured to electrically control the metasurface module 60 when an active metasurface module (e.g., the active metasurface module 60 shown in Figures 4E-4F) is used. In other embodiments, the controller 50 is configured to mechanically control the metasurface module 60 by rotating or moving it along the X, Y, or Z axis, or to align the displayed content for calibration. Once the beam is modulated by the metasurface module 60, it can be displayed to the user's eye through other optical elements such as light guides, disc lenses, aspherical lenses, bird's-eye optics, diffractive optics, etc.

[0036] Figures 4A-4H show examples of nanostructure 41, DBR layer 80U unit, and metasurface module 60 with passive and active types.

[0037] Figure 4A shows an example of a cylindrical nanostructure 41 with radius R and height H. The radius R can vary from 20 nm to 550 nm. If the desired spectrum is visible (or near-infrared or infrared), the value of H can be from 20 nm to 3000 nm.

[0038] It is worth mentioning that the operating range of metasurface modules (e.g., metasurface modules 60 shown in Figures 4C-4H, 9-11A, 13A-13D, and 18A-18F) or metasurface layers (e.g., metasurface layers 70 shown in Figures 4C-4H, 9-11A, 13A-13D, and 18A-18F) composed of multiple nanostructures 41 can be expanded. Furthermore, with proper design, metasurface modules (e.g., metasurface modules 60 shown in Figures 4C-4H, 9-11A, 13A-13D, and 18A-18F) composed of multiple nanostructures 41 can operate at different wavelengths. In one embodiment, the nanostructure 41 may have an isotropic or anisotropic shape, as shown in the examples in Figures 5A-5F. In some embodiments, the material of the nanostructure 41 is composed of dielectrics (TiO2, GaN, Si, Nb2O5, SiO2, SiC photoresist, metal oxide nanoparticles (ZrO2, TiO2) and sol-gel mixtures, etc.) or metals (such as gold, silver, aluminum, etc.) or other active materials (2D materials, VO2, GST, metal polymers) or metal polymers such as PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(-styrene sulfonate)) or any conductive polymer, but is not limited to these materials. Furthermore, multiple nanostructures 41 can be transformed into active and tunable focal length / deflection metasurface layers (see metasurface layer 70 shown in Figures 6A and 7) using any phase change material, such as GST (Ge2Sb2Te5), vanadium dioxide (VO2), and gallium (Ga), as well as other active materials, such as transparent electrooxides (e.g., ITO and AZO), thin two-dimensional materials (graphene, hBN, WS2), liquid crystals, metal polymers, etc. Therefore, programmable metasurface layers (see metasurface layer 70 shown in Figures 6A and 7) can completely or partially alter optical modulation. Furthermore, the nanostructure 41 can be fabricated using different methods, such as electron-beam lithography (EBL), deep ultraviolet (DUV) lithography, extreme ultraviolet lithography (EUV), nanoimprint lithography (NIL), and direct nanoimprinting using metal oxide nanoparticles and sol-gel mixtures.

[0039] Figure 4B shows an example of one cell of DBR layer 80U. Multiple cells of DBR layer 80U can produce DBR layer 80 of metasurface module 60 (as shown in Figures 6A and 7).

[0040] The cell spacing of the DBR layer 80U is defined as Px and Py along the x-axis and y-axis, respectively. The definition of spacing is further explained in the examples in Figures 6B and 6C. The substrate 42 shown in Figures 9, 10, and 11A can be any type of transparent / opaque substrate, such as fused silica (SiO2), sapphire (Al2O3), silicon carbide (SiC), and silicon and other materials if necessary.

[0041] Figure 4C illustrates one embodiment of a passive metasurface module 60. The metasurface module 60 may include a metasurface layer 70 and a DBR layer 80. In one embodiment, the metasurface layer 70 may have nanostructures 41, a residual resin mixture 41R, and a cladding layer 43. Each nanostructure 41 may have dimensions of radius R and height H, as shown in Figure 4A. In this embodiment, multiple direct nanoimprinted nanostructures 41 may be disposed above the DBR layer 80. The direct nanoimprinted nanostructures 41 may be made of high refractive index resin or metal oxide nanoparticles, or may be made of sol-gel mixtures such as TiO2, ZrO2, ITO, and sol-gel. After direct nanoimprinting, a residual resin mixture 41R is displayed between the direct nanoimprinted nanostructures 41 and the DBR layer 80. The cladding layer 43 is shown as an impedance matching layer, or part of a waveguide or any complementary optical element.

[0042] Figure 4D illustrates another embodiment of a passive metasurface module 60 without the covering layer 43. Figure 4D shows that the passive metasurface module 60 may include a metasurface layer 70 and a DBR layer 80. As shown in Figure 4D, the metasurface layer 70 may have nanostructures 41 without the covering layer 43 (as shown in Figure 4C). The nanostructures 41 may be made of materials as described in Figure 4A above. Multiple nanostructures 41 may be made of materials of different thicknesses (e.g., curable resins, photoresists, and dielectrics such as metal oxide nanoparticles and sol-gel mixtures), with the thickness of the nanopillars ranging from 150 nanometers to several thousand nanometers, thin depositions of metal oxides (TiO2, Al2O3, HfO2), or thicknesses of silver metals (such as gold, nano-, aluminum, etc.) ranging from 10 to 70 nanometers. However, the thickness of the nanopillars and the thin deposition of metal oxides or metals are not limited to the above ranges. In this embodiment, the nanostructures 41 may be disposed on top of a DBR layer 80. Specifically, the nanostructure 41 can be directly disposed on top of a DBR layer 80.

[0043] Figure 4E illustrates one embodiment of an active metasurface module 60. The active metasurface module 60 may include a metasurface layer 70, a DBR layer 80, and a glass layer 44. The metasurface layer 70 may have a nanostructure 41, two transparent electrodes 46, and a filler material 47. The nanostructure 41 is sandwiched between the glass layer 44 and the DBR layer 80. The glass layer 44 may be transparent or opaque. In one embodiment, a transparent electrode 46 may be deposited on one side of the glass layer 44. In addition, another transparent electrode 46 may be deposited on the DBR layer 80. The transparent electrode 46 may be, for example, indium tin oxide (ITO). The space between the two transparent electrodes 46 (not shown) is then filled with the filler material 47. In some embodiments, the filler material 47 may be an electrolyte or a gel electrolyte to make the active metasurface module 60 active. In some embodiments, the filler material 47 may be sandwiched between the two transparent electrodes 46 and surround the nanostructure 41.

[0044] Figure 4F illustrates another embodiment of an active metasurface module 60. The active metasurface module 60 may include a metasurface layer 70 and a DBR layer 80. The metasurface layer 70 may have a nanostructure 41 and a cladding layer 43. The only difference between Figure 4F and Figure 4C is that the nanostructure 41 in Figure 4F is made of active materials such as the aforementioned VO2 and 2D materials, and no residual resin mixture 41R is shown after direct nanoimprinting in Figure 4F. The cladding layer 43 is shown as an impedance matching layer, or part of a waveguide or any complementary optical element.

[0045] Figure 4G illustrates a further embodiment of the liquid crystal-based active metasurface module 60. The active metasurface module 60 may include a metasurface layer 70, a DBR layer 80, and a glass layer 44. The metasurface layer 70 may have a nanostructure 41, two transparent electrodes 46, and liquid crystal 49 filled in the space (not shown) between the two transparent electrodes 46. The nanostructure 41 is sandwiched between the glass layer 44 and the DBR layer 80, on which the transparent electrodes 46 are deposited. The glass layer 44 may be transparent or opaque. The transparent electrodes 46 are, for example, indium tin oxide (ITO). The alignment layer RL may be formed by mechanical friction (or by photo-orientation), typically formed by rubbing polyimide or other organic compounds (e.g., azo dye molecules) onto the transparent electrodes 46. The nanostructure 41 may be a dielectric or a metal (or any of the aforementioned materials). The space (not shown) between the two transparent electrodes 46 is filled with liquid crystal 49 of uniform or non-uniform thickness. The liquid crystal 49 can function in two ways. As shown in Figure 4G, one method is that the liquid crystal 49 can act as a material that modifies the ambient refractive index. The resonance of the nanostructure 41 is very sensitive to the ambient refractive index, so if the nanostructure 41 is carefully designed, the output light can be adjusted at will. As shown in Figure 4G, the second method is that if the top transparent electrode 46 (the electrode attached to the top glass layer 44) is photolithographically patterned, the liquid crystal 49 can act as a compensation and correction layer for the nanostructure 41. For example, it can form a lens like concentric rings or focus light like a strip.

[0046] Figure 4H illustrates another embodiment of the active metasurface module 60 based on phase change materials. The nanostructure 41 can be made of phase change materials, such as GST (Ge2Sb2Te5), vanadium dioxide (VO2), and gallium (Ga), but is not limited to these three materials that are primarily based on the action of the resistive heating film 41A. The cladding layer 43 is made of photoresist, resin, or any material whose refractive index matches that of the complementary optical element to be used. For example, if the proposed metasurface module 60 is required to be used in a waveguide, the cladding layer 43 should be a material with a refractive index compatible with the waveguide glass / plastic sheet.

[0047] As shown in Figures 5A-5F, each of the plurality of nanostructures 41 can be formed into different isotropic, anisotropic, or a combination of isotropic and anisotropic shapes. A metasurface module unit may contain one nanostructure (see Figures 5A-5C and 5E-5F), or a metasurface module unit may contain multiple nanostructures (see Figure 5D). Each of the plurality of nanostructures 41 in a metasurface module unit can be substantially rectangular (see Figure 5A), circular (see Figure 5B), H-shaped (see Figure 5C), L-shaped (see Figure 5E), and cross-shaped (see Figure 5F) respectively from a top view. Optionally, multiple nanostructures 41 can be formed individually in a metasurface module unit (see Figure 5D). It is understood that multiple metasurface module units can produce a single metasurface module.

[0048] Figure 6A illustrates an embodiment of a metasurface module 60, which includes multiple nanostructures 41, a coating layer 43, and a DBR layer 80. Figures 6B-6C illustrate two types of pitch definitions: center-to-center pitch (PCC) between two adjacent nanostructures 41 or edge-to-edge pitch (PEE) between two adjacent nanostructures 41. Figure 6A illustrates a metasurface module 60 comprising nanostructures 41, a DBR layer 80, and a coating layer 43. Figure 6B illustrates the center-to-center pitch (PCC) of two adjacent nanostructures 41 in every two adjacent units of the metasurface module 60U. Figure 6C illustrates the edge-to-edge pitch (PEE) of two adjacent nanostructures 41 applied in every two adjacent units of the metasurface module. The metasurface module 60 may be composed of multi-unit metasurface modules.

[0049] Figure 7 shows a schematic diagram of a DBR-based metasurface module 60 with multiple DBRs and a top view of a single arrangement 40 of nanostructures 41. The metasurface module 60 of Figure 7 includes nanostructures 41, DBR layers 80, and a coating layer 43, as shown in Figure 6A. The only difference is that a top view of a single arrangement 40 of nanostructures 41 can be seen in Figure 7. The metasurface module 60 and arrangement type 40 in a single configuration can be seen in Figures 8A-8F.

[0050] Figures 8A-8F show top views of the arrangement 40 of nanostructures 41, which have single square configurations (see Figure 8A), rectangular configurations (see Figure 8B), trapezoidal configurations (see Figure 8C), L-shaped configurations (see Figure 8D), non-overlapping configurations (see Figure 8C), L-shaped configurations (see Figure 8D), non-overlapping configurations (see Figure 8C), L-shaped configurations (see Figure 8D), square non-overlapping array configurations (see Figure 8E), and circular overlapping arrays (see Figure 8F). Therefore, the nanostructures 41 can be a single form or an array of regular or irregular configurations, and can be single-layered or multi-layered.

[0051] It is understood that the DBR layer 80 (as shown in Figures 4B-4H, 6A-7) can be either the DBR layer 801 shown in Figures 9-10 or the DBR layer 802 shown in Figure 11A. The difference between DBR layer 801 and DBR layer 802 is that, compared with DBR layer 801, DBR layer 802 also includes at least one spacer layer (Sp, as shown in Figure 11A) located between every two DBRs.

[0052] Figure 9 shows a schematic diagram of a metasurface module 60 with multiple DBRs, where there is no spacer layer (not shown, e.g., the spacer layer Sp shown in Figure 11A) between every two DBRs. The DBR-based metasurface module 60 includes at least a metasurface layer 70 and a DBR layer 801. The metasurface layer 70 includes a nanostructure 41 and a cladding layer 43. The cladding layer 43 can be considered as an impedance matching layer, or as part of other complementary optical elements such as a waveguide, or even as air. Preliminary results show that, as shown in Figure 18C, a wide reflection window (widebandpass filter) can be achieved from the DBR layer 80 with a small number of DBRs. The two alternating layers (i.e., a high-refractive-index material layer 4Hm and a low-refractive-index material layer 4Lm) have a quarter-wavelength thickness, satisfying the condition nLdLm = nHdHm = λcLHm / 4, where λcLHm (not shown) is the center wavelength. nL is the low refractive index of the low-refractive-index material layer 4Lm. nH is the refractive index of the high-refractive-index material layer 4Hm. dLm is the thickness of each low-refractive-index material layer 4Lm in the m-th DBR. dHm is the thickness of each high-refractive-index material layer 4Hm in the m-th DBR. As shown in Figure 9, the DBR layer 801 includes multiple DBRs, with a total of m DBRs. The m-th DBR consists of at least one pair of high-refractive-index material layer 4Hm and low-refractive-index material layer 4Lm. That is, each DBR consists of at least one pair of high-refractive-index material layer and low-refractive-index material layer. Nm represents the number of pairs in the m-th DBR. N1 = 6 indicates that the first DBR (DBR 1) has 6 repetitions of the pair of high-refractive-index material layer 4H1 and low-refractive-index material layer 4L1. N2 = 3 indicates that the second DBR (DBR 2) has 3 repetitions of the pair of high-refractive-index material layer 4H2 and low-refractive-index material layer 4L2. N3 = 2 indicates that the third DBR (DBR 3) has 2 repetitions of the pair of high-refractive-index material layer 4H3 and low-refractive-index material layer 4L3. Ndm represents the thickness of the m-th DBR. That is, Ndm = N1 * (dLm + dHm). For example, Nd1 = N1 * (dL1 + dH1), Nd2 = N2 * (dL2 + dH2), and Nd3 = N3 * (dL3 + dH3). For all DBRs, the low refractive index nL and the high refractive index nH can be the same or different. The low refractive index material layer 4Lm can be made of SiO2, ZnS, and Al2O3, etc., while the high refractive index material layer 4Hm can be made of Al2O3, HFO2, Ta2O5, amorphous silicon (a-Si), transparent conducting oxides (TCOs), InGaZnO4, ZnO, and ZnO:Al, etc., but is not limited to these materials. The greater the refractive index difference between a pair of high refractive index material layers 4Hm and low refractive index material layers 4Lm in the DBR, the wider the reflection window.Spacer layer 433 can be made of materials such as SiO2, SnO2, HF2, etc. The number of pairs of each DBR from N1 to Nm can be the same or different. Substrate 42 can be made of materials such as SiO2, silicon, etc. The typical pairing order is low refractive index material layer 4Lm, followed by high refractive index material layer 4Hm. However, in some embodiments, the order may be reversed or even irregular. DBR layer 801 includes all DBRs (DBR 1 to DBR m). Generally, metasurface module 60 further includes spacer layer 433 disposed under the plurality of nanostructures 41 and substrate 42 at the bottom. In one embodiment, spacer layer 433 and substrate 42 may be included in DBR layer 801 as shown in FIG. 9. In another embodiment, spacer layer 433 and substrate 42 may be excluded from DBR layer 801 (not shown). In this embodiment, spacer layer 433 is sandwiched between nanostructure 41 and all DBRs, and all DBRs are sandwiched between spacer layer 433 and substrate 42. Spacer layer 433 is used to control Fabry-Perot resonance.

[0053] Figure 10 shows a schematic diagram of a DBR-based metasurface module 60 having three DBRs, with no spacer layer (not shown, e.g., the spacer layer Sp shown in Figure 11A) between each pair of DBRs. The DBR-based metasurface module 60 includes at least a metasurface layer 70 and a DBR layer 801. The metasurface layer 70 includes a nanostructure 41 and a cladding layer 43. The cladding layer 43 can be considered as an impedance matching layer, as part of other complementary optical elements such as a waveguide, or even as air. The DBR layer 801 in Figure 10 includes three DBRs, each consisting of at least one of a high-refractive-index material layer and a low-refractive-index material layer. For the first DBR (DBR 1), N1 represents the logarithm of the first DBR. nLdL1 = nHdH1 = λcLH1 / 4, where λcLH1 (not shown) is the center wavelength. dL1 is the thickness of each low-refractive-index material layer 4L1 of the first DBR (DBR 1). dH1 is the thickness of each high-refractive-index material layer 4H1 of the first DBR (DBR 1). N1 represents the logarithm of the first DBR (N1 = 6 in DBR 1 shown in Figure 10). Nd1 represents the thickness of the first DBR (Nd1 = N1 * (dL1 + dH1)). nLdL2 = nHdH2 = λcLH2 / 4, where λcLH2 (not shown) is the center wavelength. dL2 is the thickness of each low-refractive-index material layer 4L2 of the second DBR (DBR 2). dH2 is the thickness of each high-refractive-index material layer 4H2 of the second DBR (DBR 2). N2 represents the logarithm of the second DBR (N2 = 3 for DBR 2 shown in Figure 10). Nd2 represents the thickness of the second DBR (Nd2 = N2 * (dL2 + dH2)). nLdL3 = nHdH3 = λcLH3 / 4, where λcLH3 (not shown) is the center wavelength. dL3 is the thickness of each low-refractive-index material layer 4L3 of the third DBR (DBR 3). dH3 is the thickness of each high-refractive-index material layer 4H3 of the third DBR (DBR 3). N3 represents the logarithm of the third DBR (for DBR 3 shown in Figure 10, N3 = 2). Nd3 represents the thickness of the third DBR (Nd3 = N3 * (dL3 + dH3)). The logarithms of each DBR from N1 to N3 can be the same or different. The low-refractive-index material layers can be made of SiO2, ZnS, Al2O3, etc. The high-refractive-index material layers can be made of, for example, HFO2, Ta2O5, Al2O3, amorphous silicon (a-Si), and transparent conductive oxides (TCO), InGaZnO4, ZnO, and ZnO:Al, but are not limited to these materials. The spacer layer 433 can be made of oxide materials such as SiO2, SnO2, and HF2. The substrate 42 can be made of materials such as SiO2 and silicon.Figure 10 shows all the DBRs (DBRs 1-3) beneath the nanostructure 41 in the DBR layer 801. The metasurface module 60 further includes a spacer layer 433 disposed beneath the plurality of nanostructures 41 and a substrate 42 at the bottom. In one embodiment, the spacer layer 433 and the substrate 42 may be included in the DBR layer 801 shown in Figure 10. In another embodiment, the spacer layer 433 and the substrate 42 may be excluded from the DBR layer 801 (not shown). The spacer layer 433 in Figure 10 is used for overall tuning resonance, such as controlling the Fabry-Perot resonance. The spacer layer 433 is sandwiched between the nanostructure 41 and all the DBRs, and all the DBRs are sandwiched between the spacer layer 433 and the substrate 42. The spacer layer 433 is configured to control the Fabry-Perot resonance.

[0054] Figure 11A shows a schematic diagram of a DBR-based metasurface module 60, which has multiple DBRs and at least one spacer layer Sp between every two DBRs. The DBR-based metasurface module 60 includes at least one metasurface layer 70 and a DBR layer 802, the metasurface layer 70 including nanostructures 41 and a cladding layer 43. It is understood that the difference between the DBR layer 802 shown in Figure 11A and the DBR layer 801 shown in Figures 9-10 is that the DBR layer 802 further includes at least one spacer layer Sp between every two DBRs. The cladding layer 43 can be considered as an impedance matching layer or as part of other complementary optical elements (such as waveguides), or even as air. Preliminary results show that a wide reflection window (widebandpass filter) can be achieved through the DBR layer with a small number of DBRs as shown in Figure 18C. Two alternating layers (i.e., a high-refractive-index material layer 4Hm and a low-refractive-index material layer 4Lm) have a quarter-wavelength thickness, satisfying the condition nLdLm = nHdHm = λcLHm / 4, where λcLHm (not shown) is the center wavelength, effectively reflecting electromagnetic waves. For example, as shown in Figure 11A, the DBR layer 802 contains multiple DBRs, with m DBRs in total. The m-th DBR consists of at least one pair of high-refractive-index material layer 4Hm and low-refractive-index material layer 4Lm. That is, each DBR consists of at least one pair of high-refractive-index material layer and low-refractive-index material layer. Nm represents the number of repetition pairs of the m-th DBR. N1 = 3 indicates that the first DBR (DBR 1) has 3 repetitions of the high-refractive-index material layer 4H1 and the low-refractive-index material layer 4L1. N2 = 3 indicates that the second DBR (DBR 2) has 3 repetitions of the high-refractive-index material layer 4H2 and the low-refractive-index material layer 4L2. N3 = 2 indicates that the third DBR (DBR 3) has two repeated pairs of high-refractive-index material layer 4H3 and low-refractive-index material layer 4L3. dLm is the thickness of each low-refractive-index material layer 4Lm in the m-th DBR. dHm is the thickness of each high-refractive-index material layer 4Hm in the m-th DBR. For all pairs of high-refractive-index and low-refractive-index material layers in each DBR, the low-refractive-index nL and high-refractive-index nH can be the same or different. The low-refractive-index material layer can be made of materials such as SiO2, ZnS, and Al2O3, while the high-refractive-index material can be made of materials such as HFO2, Ta2O5, Al2O3, amorphous silicon (a-Si), transparent conductive oxide (TCO), InGaZnO4, ZnO, and ZnO:Al, but is not limited to these materials. The greater the refractive index difference between a pair of high-refractive-index and low-refractive-index material layers in a DBR, the wider the reflection window. The spacer layer Sp between each two DBRs is used to adjust the resonance, and it can be made of a low refractive index material layer or a high refractive index material layer as described above (see Figure 11B).As the thickness of the spacer layer Sp (e.g., spacer layer S1 shown in Figure 11B) increases, the resonant peak shifts to longer wavelengths. Referring back to Figure 11A, spacer layer 433 can be made of materials such as SiO2, SnO2, HF2, etc. The logarithms in each DBR from N1 to Nm can be the same or different. Substrate 42 can be made of materials such as SiO2, silicon, etc. DBR layer 802 shows all the DBRs (DBR 1 to DBR m) beneath nanostructure 41. Typically, metasurface module 60 further includes spacer 433, all spacer layers Sp between every two DBRs, and substrate 42. In one embodiment, spacer layer 433, all spacer layers Sp between every two DBRs, and substrate 42 may be included in DBR layer 802 as shown in Figure 11A. In another embodiment, spacer layer 433, all spacer layers Sp between every two DBRs, and substrate 42 may be excluded from DBR layer 802 (not shown). Spacer layer 433 is used to control Fabry-Perot resonance. As the thickness of the spacer layer 433 increases, the characteristics of the resonance peak change, as shown in Figure 11C.

[0055] In some embodiments, the metasurface module 60 may include a metasurface layer 70 and a DBR layer 80. The metasurface layer 70 includes nanostructures 41 and a covering layer 43. The DBR layer 80 may be DBR layer 801 as shown in Figures 9-10 or DBR layer 802 as shown in Figure 11A. Embodiments of the metasurface module 60 having a DBR layer 801 further include a spacer layer 433, and the DBR layer 801 includes at least one DBR. The difference between embodiments with DBR layer 801 and embodiments with DBR layer 802 is that the metasurface module 60 with DBR layer 802 also includes a spacer layer Sp located between the two DBRs. Specifically, the metasurface module 60 has only one DBR layer 80, and the metasurface layer 70 has a first surface and a second surface opposite to the first surface. The first surface of the metasurface layer 70 faces the unique DBR layer 80, while the second surface of the metasurface layer 70 does not face the other DBR layer 80. In other words, the metasurface module 60 does not have two DBR layers 80, and the metasurface layer 70 is not sandwiched between two DBR layers 80. Instead, the metasurface module 60 has only one DBR layer 80, and the metasurface layer 70 has only one surface facing the DBR layer 80.

[0056] As shown in Figures 9-11A, two alternating layers (i.e., a low-refractive-index material layer and a high-refractive-index material layer) have a quarter-wavelength thickness, satisfying the condition nLdLm = nHdHm = λcLHm / 4, where λcLHm (not shown) is the center wavelength. Nm represents the number of the m-th DBR pair. dLm is the thickness of 4Lm of each low-refractive-index material layer in the m-th DBR. dHm is the thickness of 4Hm of each high-refractive-index material layer in the m-th DBR. For all DBRs, the low-refractive-index nL and high-refractive-index nH can be the same or different. That is, if the thicknesses of the low-refractive-index material layer and the high-refractive-index material layer of the DBR are changed (dLm = λcLHm / 4nL; dHm = λcLHm / 4nH), a new center wavelength will be obtained, thus enabling the fabrication of bandpass filters with different spectra. The thickness of the low-refractive-index and high-refractive-index material layers in the DBR can shift the bandwidth of the bandpass filter to a shorter or longer wavelength centered at λcLHm. Specifically, as the thickness of the low-refractive-index and high-refractive-index material layers in the DBR increases, a longer center wavelength λcLHm can be obtained due to the shift in the bandpass filter bandwidth, as illustrated in Figure 11D.

[0057] Referring to Figure 11D, Figure 11D illustrates two examples of metasurface modules 60 with low-refractive-index and high-refractive-index material layers of different thicknesses and their effect on longer center wavelengths. The bottom panel shows illustrative structures that can be applied to the metasurface modules 60 in the first and second examples of Figure 11D, respectively. The difference between the metasurface module 60 used in the first embodiment and the metasurface module 60 used in the second embodiment is that the high-refractive-index material layer 4H1 and the low-refractive-index material layer 4L1 of the metasurface module 60 used in the second embodiment are thicker. The results show that as the thickness of the high-refractive-index material layer 4H1 and the low-refractive-index material layer 4L1 of the DBR 1 increases, a longer center wavelength λcLHm can be obtained.

[0058] The term "DBR logarithm" refers to the number of repetitions of the high-refractive-index material layer and the low-refractive-index material layer in each DBR. The example shown in Figure 11E illustrates this, with metasurface module 60A showing a configuration of 3 DBRs where N is 2 (as shown in the DBR layer 80 of metasurface module 60A in Figure 11E, N1=2 for DBR 1, N2=2 for DBR 2, and N3=2 for DBR 3), and metasurface module 60B showing a configuration of 3 DBRs where the logarithm N is 3 (see the DBR layer 80 of metasurface module 60B in Figure 11E, where N1=3 for DBR 1, N2=3 for DBR 2, and N3=3 for DBR 3).

[0059] As shown in the example in Figure 11F, the metasurface module 60C, which only has a DBR layer 80 and no nanostructure 41, acts like a mirror and is used as a bandpass filter to create a specific bandwidth. The metasurface module 60D has a nanostructure 41 located on top of the DBR layer 80, and the nanostructure 41 is configured to create multiple bands within the bandwidth of the DBR layer 80 (which is closely related to the thickness of the high-refractive-index material layer and the low-refractive-index material layer).

[0060] Figures 12A-12C illustrate the embodiments of Figure 10, showing five bands when the DBR pair number is 10 (see Figure 12A), three bands when the DBR pair number is 6 (see Figure 12B), and two bands when the DBR pair number is 3 (see Figure 12C). The pair number of the DBR refers to the number of times the low-refractive-index material layer and the high-refractive-index material layer are repeated in a DBR. Specifically, a DBR composed of at least one pair of two materials with different refractive indices typically requires dozens of stacked structures to achieve high reflectivity. It is worth noting that the number of DBR pairs affects the bandwidth (reflection window). Specifically, as the DBR pair number increases, the bandwidth decreases (see Figures 12A-12C). The nanostructure 41 on top of the DBR is used to divide the light into multiple color bands and / or to divide the light into different cross-polarizations. As the logarithm of the DBR increases, the number of reflections from each layer also increases. Therefore, their interaction with the nanostructure 41 on top of the DBR will affect the number of peaks and valleys within the reflection window (bandpass filter bandwidth) created by the DBR. In other words, the number of wavelengths of light reflected by the metasurface module 60 can be determined by the logarithm of the DBR. Specifically, as the logarithm N of each DBR increases, the number of bands also increases.

[0061] Figure 13A illustrates an embodiment of a single-band metasurface module 90. The single-band metasurface module 90 of Figure 13A includes a metasurface layer 70 and a reflective layer 82. The metasurface layer 70 includes a nanostructure 41 and a cladding layer 43. The cladding layer 43 can be considered as an impedance matching layer, or as part of other complementary optical elements (such as waveguides), or even as air. The reflective layer 82 shows all the portions beneath the nanostructure 41. That is, the reflective layer 82 includes a spacer layer 433 for controlling the Fabry-Perot resonance, a thick reflective film 44, and a substrate 42. The thick reflective film 44 can be a mirror, made of a thick metallic material such as aluminum, silver, or gold. The substrate 42 can be made of materials such as SiO2 or silicon. It is understood that the single-band metasurface module 90 of Figure 13A does not include a DBR.

[0062] Figure 13B illustrates another embodiment of a single-band metasurface module 90. The difference between Figure 13B and Figure 13A is that the single-band metasurface module 90 in Figure 13B does not include the cladding layer 43 shown in Figure 13A. The single-band metasurface module 90 in Figure 13B includes a metasurface layer 70 and a reflective layer 82. The metasurface layer 70 includes nanostructures 41 but without the cladding layer 43, as shown in Figure 13A. The reflective layer 82 shows all the portions beneath the nanostructures 41. That is, the reflective layer 82 includes a spacer layer 433, a thick reflective film 44, and a substrate 42. The thick reflective film 44 can be considered as a mirror made of a thick metallic material such as aluminum, silver, or gold. The substrate 42 can be made of materials such as SiO2 or silicon. It is understood that the single-band metasurface module 90 in Figure 13B does not include a DBR.

[0063] Figure 13C illustrates a further embodiment of the single-band metasurface module 90. The difference between Figure 13C and Figure 13A is that the single-band metasurface module 90 in Figure 13C also includes a non-uniform spacer layer 433NU. The single-band metasurface module 90 in Figure 13C includes a metasurface layer 70 and a reflective layer 82. The metasurface layer 70 includes a nanostructure 41 and a cladding layer 43. The cladding layer 43 can be considered as an impedance matching layer, or as part of other complementary optical elements such as a waveguide, or even as air. The reflective layer 82 shows all the portions beneath the nanostructure 41. That is, the reflective layer 82 includes the cladding layer 43, the spacer layer 433NU controlling the Fabry-Perot resonance, a thick reflective film 44, and a substrate 42. The thick reflective film 44 can be a mirror made of a thick metallic material such as aluminum, silver, or gold. The substrate 42 can be made of materials such as SiO2 or silicon. It is understandable that the single-band metasurface module 90 in Figure 13C does not include the DBR.

[0064] Figure 13D illustrates an embodiment of a single-band metasurface module 90. The difference between Figure 13D and Figure 13C is that the single-band metasurface module 90 of Figure 13D does not include the cladding layer 43 shown in Figure 13C. The single-band metasurface module 90 includes a metasurface layer 70 and a reflective layer 82. The metasurface layer 70 includes a nanostructure 41. The reflective layer 82 shows all the portions below the nanostructure 41. That is, the reflective layer 82 includes a spacer layer 433NU for controlling the Fabry-Perot resonance, a thick reflective film 44, and a substrate 42. The thick reflective film 44 can be a mirror made of a thick metallic material such as aluminum, silver, or gold. The substrate 42 can be made of materials such as SiO2 or silicon. It is understood that the single-band metasurface module 90 of Figure 13D does not include a DBR.

[0065] It is understood that the spacer layer 433 and the non-uniform spacer layer 433NU are configured to generate resonance to modulate the phase (amplitude) of the incident light. It is understood that the difference between the reflective layer 82 (as shown in Figures 13A-13D) and the DBR layer 80 is that the reflective layer 82 does not include the DBR.

[0066] Figure 14 shows an example of a single-band metasurface module 90 (e.g., the single-band metasurface module 90 shown in Figures 13A-13D, one for the cyan band (approximately 450 nm) and another for the red band (approximately 650 nm), with at least one overlapping band). Unlike Figures 9, 10, and 11A, these figures can use an array of nanostructures 41 of only one type with only one shape (e.g., a rectangular nanostructure, as shown in Figure 17A) to generate multiple bands. When there is no DBR under the nanostructure 41 (as in the designs in Figures 13A-13D), the single-band metasurface module 90 will be able to excite and modulate only one peak in the reflection window (unlike Figures 12A-12C), whose bandwidth and amplitude characteristics are very difficult to control. Furthermore, to create the cyan and red bands, the designs in Figures 13A-13D require the use of at least two different types of nanostructures 41 with different sizes, and there is no DBR beneath the nanostructures 41. These single-band metasurface modules 90 are designed to exhibit minimal crosstalk. However, due to their wide bandwidth and lower resonance quality, the presence of crosstalk after fabrication is unavoidable.

[0067] Figure 15 shows that the thickness of each layer provided in the examples in Figures 9, 10, 11A, and 13A-13D can be completely uniform (t1=t2=t3=t4) or non-uniform (t1≠t2≠t3≠t4), or it can be uniform in some aspects and non-uniform in others. For example, the thickness of the substrate 42, spacer layer 433, cladding layer 43, DBR in Figures 9-11A and the spacer layer Sp in Figure 11A can be non-uniform, and the thickness of the substrate 42, thick reflective film 44, spacer layer 433, cladding layer 43, and non-spacer layer 433NU in Figures 13A-13D can be non-uniform.

[0068] Figures 16A-16B show the half maximum (FWHM) and amplitude engineering for single-band (see Figure 16A) and multi-band (see Figure 16B). By adjusting the geometric parameters (e.g., thickness, height, length, width, material) of each layer in Figures 13A-13D and Figures 9, 10, and 11A, bandwidth, FWHM, quality factor, amplitude, and shifting the peak to the desired wavelength (e.g., λA, λB, and λC) can be achieved, as shown in Figures 9, 10, and 11A.

[0069] Figures 17A-17E show five examples of nanostructure arrangements 40, whose shapes can vary from isotropic to anisotropic or a combination of isotropic and anisotropic nanostructures 41.

[0070] Figure 17A illustrates an embodiment of the Pancharatnam-Berry (PB) phase arrangement 40, wherein nanostructures 41 with identical anisotropic shapes are disposed in the proposed metasurface module (not shown). The proposed metasurface module operates by having a nanostructure 41, which undergoes a phase transition by replicating and simultaneously rotating the nanostructure 41 in a certain direction, thereby forming a supercell and achieving a phase transition of 2π or higher. If the desired spectrum is visible light (or near-infrared or infrared), the length and width of the rectangular nanostructure 41 can vary from 20 nm to 550 nm, and the height of the nanostructure 41 can have values ​​from 20 nm to 3000 nm. It is worth noting that the operating range of the proposed metasurface module is scalable. Furthermore, if the nanostructure 41 is designed properly, the metasurface module with the nanostructure 41 can operate at different wavelengths.

[0071] Figure 17B illustrates another embodiment of the propagation stage arrangement 40, wherein an isotropic nanostructure 41 is disposed within the proposed metasurface module (not shown). The proposed metasurface module operates by generating the desired phase transition by varying the dimensions of the isotropic nanostructure. If the desired spectrum is visible light (or near-infrared or infrared), the radius of the nanopillars can vary from 10 nm to 400 nm, and the height of the nanostructure 41 can have values ​​from 20 nm to 3000 nm. Notably, the operating range of the proposed metasurface module is scalable. Furthermore, if the nanostructure is designed properly, the metasurface module with the nanostructure 41 can operate at different wavelengths.

[0072] Figure 17C illustrates another embodiment of a complex-shaped nanostructure arrangement 40 for a deflection metasurface module (not shown), wherein the desired phase transition is achieved through different anisotropic nanostructures 41 of varying shapes, with dimensions smaller than the spacing (PCC or PEE) described in Figures 6A-6C. The spacing value can range from 150 nm to 800 nm. If the desired spectrum is visible light (or near-infrared or infrared), the height of the nanostructures can range from 20 nm to 3000 nm. Notably, the proposed metasurface module has an scalable operating range. Furthermore, if the nanostructures 41 are designed appropriately, the metasurface module with the nanostructures 41 can operate at different wavelengths.

[0073] Figure 17D shows a static embodiment of a complex-shaped nanostructure arrangement 40 of a deflection metasurface module (not shown), including a PB phase and a propagation phase scheme, comprising isotropic and anisotropic nanostructures 41, such as those described in Figures 5A-5F. The desired phase transition is achieved through the aforementioned nanostructures 41, whose dimensions are smaller than the spacing (PCC or PEE) described in Figures 6A-6C. The spacing value can range from 150 nm to 800 nm. If the desired spectrum is visible light (or near-infrared or infrared), the height of the nanostructures 41 can have a value from 20 nm to 3000 nm. It is worth noting that the operating range of the proposed metasurface module is scalable. Furthermore, if the nanostructures 41 are designed properly, the metasurface module with the nanostructures 41 can operate at different wavelengths.

[0074] Figure 17E shows another embodiment of an arrangement 40 of a supergrating structure nanostructure 41 for a deflecting metasurface module (not shown) for deflecting light. The width of the supergrating structure nanostructure 41 should be smaller than the spacing (PCC or PEE) described in Figures 6A-6C. The spacing value can be from 150 nm to 800 nm. If the desired spectrum is visible light (or near-infrared or infrared), the height of the nanostructure 41 can have a value from 20 nm to 3000 nm. It is worth mentioning that the operating range of the proposed metasurface module is scalable. Furthermore, if the nanostructure 41 is designed properly, the metasurface module can operate at different wavelengths. It is noteworthy that the grating strips can be continuous or discrete, such as in a catenary configuration.

[0075] Figures 18A-18E show that the proposed metasurface module can be designed as a deflecting metasurface, a metalens, an orbital angular momentum generator or a classifier, depending on the application, and can be polarization-dependent or polarization-independent.

[0076] Figure 18A shows a schematic diagram of the working principle of the proposed metasurface module 60. Once broadband light is incident on the metasurface module 60 from a light source (not shown) or a display (not shown), the metasurface module 60 separates the broadband light into a specific number of wavelengths (depending on the design of the metasurface module 60) and reflects the light to a specified angle. Specifically, in the embodiments disclosed herein, the metasurface module 60 includes a metasurface layer 70 and a DBR layer 80. The metasurface layer 70 includes nanostructures 41 and a cladding layer 43. It is understood that in other embodiments, a metasurface module 60 without the cladding layer 43 can also be applied to the embodiment of Figure 18A.

[0077] Figure 18B shows a schematic diagram of the working principle of the 3D AR glasses 100, where each eye has a different color band compared to the other eye. Specifically, in the 3D AR glasses 100, each eye has a color band with opposite colors compared to the other eye. In Figure 18B, R, G, B, C, M, and Y represent the red, green, blue, cyan, magenta, and yellow color bands, respectively. Light can be cross-polarized from one eye to the other. For example, one eye receives right-handed circularly polarized (RCP) light while the other eye receives left-handed circularly polarized (LCP) light. However, the 3D AR glasses 100 can be designed to allow both eyes to support the same type of polarization. The 3D AR glasses 100 also supports linear and circular polarization, or can be designed to be polarization-independent. By carefully adjusting the DBR and metasurface geometry parameters, three color bands (e.g., red, green, and blue) can be created to cover the desired color band for the left eye, and one or three complementary color bands (e.g., cyan, magenta, and yellow) can be created for the right eye. Specifically, this application discloses an optical device for 3D imaging, wherein the optical device is, for example, the 3D AR glasses 100 shown in FIG. 18B. This optical device includes two different metasurface modules (not shown, e.g., metasurface module 60 shown in FIG. 18A). One of the two different metasurface modules is configured to create one or more color bands for the left eye, and the other of the two different metasurface modules is configured to create one or more different color bands for the right eye. In some embodiments, the two different metasurface modules of the optical device have different DBRs, thereby creating different color bands for the two eyes. In some embodiments, the two different metasurface modules of the optical device have different metasurface layers (or nanostructures 41) to create different color bands for the two eyes. In some embodiments, the two different metasurface modules of the optical device have different DBRs and / or different metasurfaces (or nanostructures 41) to create different color bands for the two eyes. In this binocular optical device, the different color bands generated by the two different metasurface modules can be any complementary color bands.

[0078] Figure 18C shows a schematic diagram of a band-tuned reflection window (similar to a bandpass filter) design for a distributed Bragg reflector (DBR) using repeating pairs of high-refractive-index and low-refractive-index material layers. The top panel shows the narrow reflection window when using only one DBR. The middle panel shows a wider reflection window when using two DBRs, where two overlapping narrow-band DBRs are merged to create a wider reflection window. The bottom panel shows the widest reflection window when using three DBRs, where three overlapping narrow-band DBRs are merged to create an ultra-wide reflection window. However, it is not limited to three DBRs.

[0079] When two DBRs made of the same material but with different center wavelengths (λcLH) and a certain offset are carefully combined, a wider reflection window appears due to the overlap of the DBR bands forming a wider band. This DBR has greater freedom compared to DBR technology that uses only a pair of high-refractive-index material layers and low-refractive-index material layers with higher contrast between the high and low refractive indices. For example, a DBR made of SiO2 / α-Si with high-refractive-index material layers and low-refractive-index material layers has a wider reflection band than materials with lower contrast (such as SiO2 / HfO2 or SiO2 / Ta2O5). The bandwidth (∆λ) of the reflection window is a function of the refractive index, i.e., Δλ=(4*λcLH / π) *arcsin((nH-nL) / (nH+nL)). Therefore, the reflection window widens when the refractive index difference between the high-refractive-index material layer and the low-refractive-index material layer increases (n2-n1). However, DBRs with high-contrast materials or even different materials can form ultra-wide reflection windows. Therefore, by adjusting the design parameters of the DBR and its materials, a wide reflection band can be obtained. Then, a nanostructure array is needed to form a multi-resonant (multi-band) scheme within the reflection window of the DBR.

[0080] Figure 18D shows simulation results for at least one DBR-based deflecting metasurface module (not shown). In the top panel, the DBR-based deflecting metasurface module transmits blue, green, and red bands. The bottom panel represents another DBR-based deflecting metasurface module that operates in the cyan and yellow bands. As shown, the overlap bands between the left and right eyes are minimized. Specifically, the visible light and complementary color bands are finite, therefore the number of bands in the visible spectrum is finite. Thus, one eye has 1 to 3 bands, and the other eye has 1 to 3 bands. Figure 18D shows that at least two metasurface modules (a combination of DBR and metasurface) can support 5 different bands, with 3 bands for the left eye and 2 bands for the right eye. Therefore, for the left eye, a DBR with a wider bandwidth is needed to support 3 bands. Furthermore, for the right eye, only two bands require different DBRs with narrower bandwidths. Specifically, "different DBRs" refers to different designs, different center wavelengths, and different thicknesses of high-refractive-index and low-refractive-index material layers. The number of peaks in the left eye (three peaks) and the right eye (two peaks) are also different, which means that the DBR logarithms are different. However, it can be considered that there are some differences in nanostructure 41 in the left and right eyes. In other embodiments, if only one or two color bands are used for one eye and one or two color bands are used for the other eye, then only one DBR from the two metasurface modules (one metasurface module for one eye and the other metasurface module for the other eye) can be used to limit the desired color bands, and then one DBR from the different surface metasurface modules of the two metasurface modules is used for the precise color, thereby creating different color bands for the two eyes.

[0081] Figure 18E shows the phase coverage corresponding to the color bands presented in Figure 18D. All color bands support 2π (and above) phase gradients, thus allowing complete control over the light of different color bands, unlike the simple reflection designs shown in Figures 13A-13D, which typically support only one broadband phase gradient at a time.

[0082] According to one embodiment, the upper left panel of FIG18F shows three paired repetitions (N1 = 3) of the high-refractive-index material layer and the low-refractive-index material layer in the DBR. According to one embodiment, the top middle panel of FIG18F shows six paired repetitions (N1 = 6) of the high-refractive-index material layer and the low-refractive-index material layer in the DBR. According to one embodiment, the upper right panel of FIG18F shows nine paired repetitions (N1 = 9) of the high-refractive-index material layer and the low-refractive-index material layer in the DBR. The bottom panel of FIG18F shows the cutoff of the DBR window for the repeated high-refractive-index material layer and the low-refractive-index material layer in the DBR according to one embodiment. The drawing bottom panel of FIG18F shows the cutoff of the DBR window according to the embodiments of the upper left, upper middle, and upper right panels of FIG18F, wherein the high-refractive-index material layer and the low-refractive-index material layer in the DBR have different pairs of repetitions.

[0083] As shown in the example in Figure 18F, as the logarithm N1 of the DBR increases, the cutoff shape of the DBR window becomes more square, and the cutoff frequency becomes more accurate. Here, cutoff refers to the start or end position of the bandpass filter. Furthermore, when the logarithm N1 of the DBR is not large enough, the start and end points of the frequency band will be curved, resulting in insufficient efficiency of the DBR.

[0084] Figures 19A-19C illustrate schematic diagrams of the potential applications of at least one metasurface module of an optical device (not shown) in waveguides, disc or aspherical lenses, and bird's-eye or freeform surface optical elements. As shown in Figures 19A-19C, at least one metasurface module may include: a first metasurface module 60E configured to create one or more color bands (e.g., R, G, B) for the left eye; and a second metasurface module 60F configured to create one or more different color bands (e.g., Y, M, C) for the right eye. The different color bands formed by the first metasurface module 60E and the second metasurface module 60F of the binocular optical device can be any complementary color bands. In Figures 19A-19C, R, G, B, C, M, and Y represent red, green, blue, cyan, magenta, and yellow color bands, respectively. Figure 19A shows at least one metasurface module of an optical device (not shown) in a waveguide, with the angle of incidence relative to at least one metasurface module (i.e., first metasurface module 60E and second metasurface module 60F) to be well controlled. Tuning stage 61 can mechanically or electrically move or rotate at least one metasurface module. Figure 19B shows at least one metasurface module (i.e., first metasurface module 60E and second metasurface module 60F) of an optical device (not shown) with a disc lens or aspherical lens, wherein display 10 is located outside the center to ensure that at least one metasurface module (i.e., first metasurface module 60E and second metasurface module 60F) is designed with a metamirror working lens or a second metasurface module 60E and a second metasurface module. Tuning stage 61 can mechanically or electrically move or rotate at least one metasurface module. Figure 19C shows at least one metasurface module (i.e., first metasurface module 60E and second metasurface module 60F) of an optical device (not shown) with bird's-eye or freeform surface optical elements. At least one metasurface module (i.e., the first metasurface module 60E and the second metasurface module 60F) may be placed in the first reflective surface (as shown in the schematic diagram) or in the second reflective surface (if any). The tuning stage 61 may mechanically or electrically move or rotate at least one metasurface module.

[0085] Figures 20A-20D illustrate one application of the proposed metasurface module in an optical device. For example, the proposed metasurface module is designed to address color arrangement and crosstalk between the right and left eye glasses. Figure 20A shows a schematic diagram of a 3D glasses 100 with two displays to generate consistent parallax for the left and right eyes, and then employs a color mapping algorithm to ensure realistic color effects while considering depth continuity and active depth cutting. Furthermore, the 3D glasses 100 of Figure 20A can be applied to the schemes of Figures 19A to 19C. In addition, a field-sequential color system can be built on the proposed metasurface module to further reduce color separation and provide higher light output, spatial resolution, and a wide color gamut. For LBS displays, Lissajous scanning technology can be used to further adjust colors and improve image quality through software. Figure 20B shows the corresponding reflection spectrum of the diffractive optical element (DOE) (in this example, our proposed metasurface module) for each eye, with the top panel representing the left eye and the bottom panel representing the right eye. By carefully designing DBR-based metasurface modules (see Figure 20C), crosstalk can be minimized. Therefore, different scenarios as shown in Figure 20D can be applied, in the following order from top to bottom: cyan-red, green-magenta, blue-yellow, blue and green-blue and red, and amber-blue. However, these combinations are not the only possibilities. It is worth noting that each eye can have one or more metasurface modules.

[0086] Figure 21 illustrates another application of the proposed DBR-based metasurface module 60 in optical detection devices, such as optical angular momentum (OAM) generators or classifiers, superlenses, Raman spectroscopy and other spectral applications, and time-of-flight (ToF) sensing applications. The proposed metasurface module 60 can replace a conventional grating to separate spectral bands with higher resolution. In Figure 21, the proposed DBR-based metasurface module 60 can be applied to an optical device (not shown), which may include a light source (not shown, or a display), at least one concave lens (e.g., concave lenses 71 and 72), the proposed metasurface module 60, and a detector 73. Light emitted from the light source (not shown) or the display (not shown) is reflected by the concave lens 71, and then the metasurface module 60 reflects the reflected light towards the concave lens 72. The concave lens 72 then reflects the reflected light towards the detector 73. The metasurface module 60 is configured to separate light into multiple color bands and / or into light with different cross-polarizations, so that the detector 73 can receive light with multiple color bands and / or light with different cross-polarizations. Furthermore, as previously mentioned, the metasurface module 60 can be made of active materials or in combination with active materials, thus providing more flexible options for adjusting and calibrating the spectrum.

[0087] Spectroscopic measurements of irradiance variations within the wavelength domain can provide information corresponding to the chemical composition of materials. Therefore, based on the solubility of the diffuser, more data can be used to distinguish between two materials with slightly different chemical compositions. Existing reflective blazed gratings are typically fabricated on convex surfaces, which increases the risk of manufacturing defects. However, some blazed gratings fabricated on planar surfaces have lower optical performance. Furthermore, the calibration of conventional diffraction diffusers is challenging; reflections can change over time, their long-term stability is controversial, and if poorly manufactured, they can be susceptible to chromatic aberration and axial aberrations, radial field curvature, and other types of aberrations or distortions. Therefore, a metasurface module 60 based on hyperspectral DBR is introduced as a diffuser. The DBR-based metasurface module 60 requires simple fabrication, has high tolerance for manufacturing errors, allows for simple calibration in active mode, has ultra-fine resolution, and can be designed according to the resolution required for each system (e.g., the embodiments in Figures 12A-12C).

[0088] It should be noted that any step or technical feature of the above embodiments of this application can be freely and arbitrarily combined. The combined technical solution is also within the scope of this application.

[0089] It is understood that, in order to achieve the above-mentioned functions, the detection device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0090] In this embodiment, the detection device can be divided into functional modules according to the above method example. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or software. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0091] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all changes falling within the meaning and scope of equivalents of the claims are intended to be included within this application.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application. [Simplified Explanation of the Diagram]

[0015] Figure 1A shows a prior art 3D imaging glasses with color filter glasses, using cyan and red color bands as an example (i.e., the color bands can be any complementary color bands, such as red-cyan, green-violet, yellow-blue). Figure 1B shows another prior art 3D imaging glasses with cross-polarized glasses, which can be linear polarizers or circular polarizers. Figure 1C shows a prior art 3D imaging glasses with shutter glasses, which flips between images faster than the human eye's detection rate (frames per second), thus creating the illusion of motion. Figure 1D shows a prior art 3D imaging glasses that captures surrounding objects through a camera, then reconstructs 3D images from the objects, and displays them to the user through the display of AR / VR / MR glasses. Figure 2A shows the application of a metasurface element or metasurface module proposed according to one embodiment of this application in waveguide-based AR / VR / MR glasses. Figure 2B shows the application of a metasurface element or metasurface module proposed according to another embodiment of this application in pancake-based AR / VR / MR glasses. Figure 2C illustrates the application of the proposed metasurface element or proposed metasurface module according to another embodiment of this application in a freeform AR / VR / MR glasses. Figure 3 shows a schematic diagram of an AR / VR / MR glasses including the proposed metasurface module according to an embodiment of this application. Figures 4A-4H show examples of nanostructures, DBR layer units, and metasurface modules of passive and active types according to some embodiments of this application. Figures 5A-5F show top views of the geometry of one or more nanostructures according to some embodiments of this application. Figures 6A-6C show embodiments of metasurface modules and two spacing definitions applied in every two adjacent units of metasurface module 60U. Figure 6A shows an embodiment of metasurface module 60. Figure 6B shows an embodiment of one spacing definition (center to center) applied in every two adjacent units of metasurface module 60U. Figure 6C shows an embodiment of another type of spacing definition (edge ​​to edge) applied in every two adjacent units of metasurface module 60U. The metasurface module 60 may be composed of multiple metasurface modules 60U. Figure 7 shows a schematic diagram of a DBR-based metasurface module 60 with multiple pairs of high-refractive-index material layers and low-refractive-index material layers, and a top view of a single square arrangement 40 of nanostructures 41. The types of metasurface modules 60 and arrangements 40 in a single configuration can be seen. Figures 8A-8F show some embodiments of the top view of the arrangement 40 of nanostructures 41 that produces the metasurface array in Figure 7. Figure 8A shows a single square configuration, Figure 8B shows a rectangular configuration, Figure 8C shows a trapezoidal configuration, Figure 8D shows an L-shaped configuration, Figure 8E shows a square non-overlapping array configuration, and Figure 8F shows a circular overlapping array.However, the top view of the nanostructure arrangement 40 is not limited to these shapes and configurations. Figure 9 shows a schematic diagram of a DBR-based metasurface module with one spacer layer 433 and m DBRs, and no spacer layer between each pair of DBRs. Figure 10 shows a schematic diagram of a DBR-based metasurface module with one spacer layer 433 and three DBRs, and no spacer layer between each pair of DBRs. Figure 11A shows a schematic diagram of a DBR-based metasurface module with one spacer layer 433 and multiple DBRs, including spacer layers Sp located between each pair of DBRs. Figure 11B shows a schematic diagram of a DBR-based metasurface module. Another figure shows the effect of applying spacer layers Sp of different thicknesses (here p=1) between each pair of DBRs on the reflected light of the DBR-based metasurface module. Figure 11C shows a schematic diagram of a DBR-based metasurface module. Another figure shows the effect of DBR-based metasurface modules on reflected light, depicting the influence of spacer layers 433 of varying thicknesses located between metasurface layer 70 and all DBRs. Figure 11D shows schematic diagrams of two examples of DBR-based metasurface modules. Another figure shows the effect of DBR-based metasurface modules on reflected light, depicting the effect of DBR thickness variations on reflected light. Figure 11E shows two examples of DBR-based metasurface modules with three DBRs, each with a different logarithm. Figure 11F shows a comparison of the bandwidth produced by a DBR layer without nanostructures with the bandwidth produced by the same DBR layer with nanostructures. Figures 12A-12C show examples of band tuning and the number of bands in multi-band schemes, five bands (color), three bands (color), and two bands (color), respectively. Figures 13A-13D illustrate single-band nanostructures: (A) a cladding with a spacer layer 43 of uniform thickness; (B) a cladding with a spacer layer 43 of non-uniform thickness; (C) a cladding with at least one spacer layer 433NU of non-uniform thickness; and (D) a cladding with a spacer layer 43NU of non-uniform thickness. Figure 14 shows an example of band tuning in a single-band scheme based on the single-band structure of Figures 13A-13D. Figure 15 shows that the unit thickness of each layer of the proposed metasurface module can be completely uniform (t1=t2=t3=t4) or completely non-uniform (t1≠t2≠t3≠t4), or some can be uniform while others can be non-uniform. Figures 16A and 16B show the bands and amplitudes of the single-band (A) and multi-band (B) metasurface module. Figures 17A-17E illustrate five examples of nanostructure arrangements with different shapes configured in the proposed metasurface module. In these examples, the shapes of the nanostructures can vary from isotropic to anisotropic or a combination of isotropic and anisotropic shapes.Figure 18A shows a schematic diagram of the proposed metasurface module with DBR for multi-band (or single-band) color separation. Figure 18B shows a schematic diagram of the proposed metasurface module, where the DBR is applied to a pair of proposed glasses. Each eye receives different color bands with different polarizations. R, g, B, C, M, and Y represent the red, green, blue, cyan, magenta, and yellow color bands, respectively. Figure 18C shows a schematic diagram of the band tuning of a distributed Bragg reflector (DBR) using repeating pairs of high-refractive-index and low-refractive-index material layers. The top panel shows a DBR layer with one DBR, the middle panel shows a DBR layer with two DBRs, and the bottom panel shows a DBR layer with three DBRs. Figure 18D shows schematic diagrams of the left eye (top panel) and right eye (bottom panel) of the DBR-based metasurface module. Figure 18E shows the relationship between the Pancharatnam-Berry (PB) phase distribution and nanostructure rotation. As shown, all color bands support phase changes from 0 to 2π and above. Figure 18F illustrates an example of how increasing the logarithm N1 of the DBR affects the bandwidth of the DBR. Figures 19A-19C show three types of glass used for applications of the proposed metasurface module: Figure 19A waveguide, Figure 19B pancake aspherical lens, and Figure 19C freeform. However, the applications are not limited to these. Notably, the proposed metasurface module can be mechanically or electrically rotated and / or adjusted. Figures 20A-20D illustrate one application of the proposed metasurface module in optical devices. For example, the proposed metasurface module is designed to address color alignment and crosstalk in right and left eye glasses. Here, DOE represents a diffractive optical element, i.e., the metasurface module proposed in this paper. Figure 21 illustrates another application of the proposed metasurface module in optical detection devices, such as optical angular momentum (OAM) generators or classifiers, superlenses, Raman spectroscopy and other spectral applications, and time-of-flight (ToF) sensing. [Biomaterial Storage]

[0094] None

Claims

1. A metasurface module, wherein the improvement is that the metasurface module comprises: Distributed Bragg Reflector (DBR) layer; and a metasurface layer disposed on the DBR layer, the metasurface layer comprising: a plurality of nanostructures arranged on the DBR layer, the plurality of nanostructures being arranged in a preset configuration, the plurality of nanostructures being configured to change the light modulation of light emitted from the light source and to separate the spectrum of the light into a plurality of specific bands.

2. The metasurface module as described in claim 1, wherein, The metasurface layer further includes a coating layer that coats the plurality of nanostructures.

3. The metasurface module as described in claim 1, wherein, The metasurface layer also includes a residual resin mixture disposed between the plurality of nanostructures and the DBR layer.

4. The metasurface module as described in claim 1, wherein, The multiple nanostructures are composed of high-refractive-index resin or metal oxide nanoparticles.

5. The metasurface module as described in claim 1, wherein, The multiple nanostructures are composed of phase change materials.

6. The metasurface module as described in claim 1, wherein, Each of the plurality of nanostructures is an isotropic, anisotropic, or a combination of isotropic and anisotropic shapes.

7. The metasurface module as described in claim 1, wherein, The DBR layer comprises at least one DBR, each DBR consisting essentially of at least one pair of high refractive index material layers and low refractive index material layers, each of the at least one DBR comprising a different number of high refractive index material layers and low refractive index material layers.

8. The metasurface module as described in claim 1, wherein, The metasurface module further includes at least one spacer layer disposed under the plurality of nanostructures.

9. An optical device, improved in that the optical device comprises: At least one light source; and at least one metasurface module as claimed in any one of claims 1 to 8, the at least one metasurface module being configured to receive light from the at least one emitting light source and to reflect the light toward a target.

10. An optical device as claimed in claim 9, wherein the optical device is AR / VR / MR glasses or an optical detection device.