Design method for metasurface non-staggered polarization multiplexing holographic display device

Abstract

The invention discloses a design method for a metasurface non-staggered polarization multiplexing holographic display device, and the method comprises the steps: carrying out the phase analysis of an initial polarization detection signal according to a phase recovery algorithm, and obtaining phase analysis information; receiving an incident polarized light signal and an emergent polarized light signal to construct emergent light complex amplitude, and combining phase analysis information to obtain analysis parameters corresponding to all positions in the metasurface device; constructing corresponding structure-phase delay mapping according to scanning information obtained by scanning, and further performing matching mapping on the analysis parameters to obtain corresponding mapping information; according to the mapping information, microstructure geometric parameters of all positions in the metasurface device are restored, and metasurface device design information is obtained. According to the design method, the holographic display device capable of carrying out independent phase regulation and control on any three polarization states can be designed, and the limitation that a non-staggered metasurface can only aim at orthogonal polarization state regulation and control is broken through; moreover, high-spatial-resolution display imaging can be realized, and the imaging field angle is larger.

Description

Technical Field

[0001] This invention relates to the field of metasurface device technology, and in particular to a design method for metasurface non-interlaced polarization multiplexing holographic display devices. Background Technology

[0002] Holographic display technology has significant application value in fields such as 3D display, near-eye display, augmented reality (AR), and virtual reality (VR). With the development of nanotechnology, a two-dimensional metamaterial based on artificial microstructures—the metasurface—has been proposed. It is a two-dimensional planar material composed of subwavelength-scale artificial microstructure units, capable of flexibly controlling the amplitude, phase, and polarization characteristics of light waves at the subwavelength scale by precisely designing the geometry, size, and arrangement of its structural units. Due to its large field of view, high diffraction efficiency, and high integration, metasurfaces provide support for the further development of holographic technology.

[0003] To further enhance the performance and flexibility of metasurface holographic displays, polarization-multiplexed metasurface holographic displays have emerged. By controlling the polarization states of the incident and outgoing light, multiple independent holograms can be displayed on the same metasurface. This design not only significantly improves the information capacity and functional integration of the metasurface, but also represents one of the important development directions for metasurface holographic display technology.

[0004] However, existing metasurfaces using non-interlaced polarization multiplexing primarily control the same-polarization and orthogonal polarization components within orthogonal polarization, rather than providing independent control over arbitrary polarizations, resulting in insufficient polarization control capability. Furthermore, while interlaced metasurfaces achieve multiple polarization multiplexing, they reduce spatial resolution and field of view, and introduce crosstalk, leading to poor image quality in holographic imaging. Therefore, existing multi-channel polarization multiplexing metasurface display devices suffer from insufficient control capability. Summary of the Invention

[0005] This invention provides a design method for a metasurface non-interlaced polarization multiplexed holographic display device, aiming to solve the problem of insufficient control capability in existing multi-channel polarization multiplexed metasurface display devices.

[0006] In a first aspect, embodiments of the present invention provide a design method for a metasurface non-interlaced polarization multiplexing holographic display device, wherein the design method is applied in a processing terminal of a design system, the processing terminal being communicatively connected to a transmitter and an analyzer to achieve data information transmission, the metasurface device being disposed between the transmitter and the analyzer with the microstructure layer in the metasurface device facing the analyzer, and the design method comprising: The initial polarization signal obtained by the analyzer is phase-analyzed according to a preset phase recovery algorithm to obtain the corresponding phase analysis information. The initial polarization signal includes image polarization signals corresponding to at least three optical signal images with different polarization states. Receive the incident polarized light signal from the transmitter and the outgoing polarized light signal from the analyzer, and construct the corresponding complex amplitude of the outgoing light; The complex amplitude of the emitted light is analyzed based on the phase analysis information to obtain the analytical parameters corresponding to each position in the metasurface device; The corresponding structure-phase delay map is constructed based on the scanning information obtained from scanning the rectangular microstructure; The parsing parameters are matched and mapped according to the preset mapping rules and the structure-phase delay mapping to obtain the corresponding mapping information; Based on the mapping information, the microstructure geometric parameters at each location in the metasurface device are reconstructed to obtain the corresponding metasurface device design information.

[0007] Secondly, embodiments of the present invention also provide a design system for a metasurface non-interlaced polarization multiplexing holographic display device, wherein the design system includes a processing terminal, a transmitter, and an analyzer, the processing terminal being communicatively connected to the transmitter and the analyzer to realize data information transmission, the metasurface device being disposed between the transmitter and the analyzer, and the transmitter, the metasurface device, and the analyzer being arranged sequentially along the same optical axis; The microstructure layer in the metasurface device is oriented toward the polarizer; The processing terminal is used to execute the design method for a metasurface non-interlaced polarization multiplexing holographic display device as described in the first aspect above.

[0008] This invention provides a design method and system for a metasurface non-interlaced polarization multiplexing holographic display device. The method involves performing phase analysis on an initial polarization detection signal using a phase retrieval algorithm to obtain phase analysis information. The method then receives the incident and outgoing polarized light signals to construct the complex amplitude of the outgoing light and combines this with the phase analysis information to obtain analytical parameters corresponding to each position in the metasurface device. Based on the scanning information obtained from the scan, a corresponding structure-phase delay mapping is constructed, and the analytical parameters are further matched and mapped to obtain corresponding mapping information. Finally, the microstructure geometric parameters at each position in the metasurface device are reconstructed based on the mapping information to obtain the metasurface device design information. This design method enables the design of a holographic display device that allows independent phase modulation of three arbitrary polarization states, overcoming the limitation that non-interlaced metasurfaces can only modulate orthogonal polarization states. Furthermore, it achieves high spatial resolution display imaging and a larger imaging field of view. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a flowchart of a design method for a metasurface non-interlaced polarization multiplexing holographic display device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating an application scenario of the design method for a metasurface non-interlaced polarization multiplexing holographic display device provided in an embodiment of the present invention. Figure 3 The phase resolution information provided in the design method for a metasurface non-interlaced polarization multiplexing holographic display device according to embodiments of the present invention; Figure 4 This is a schematic diagram of the rectangular microstructure provided in an embodiment of the present invention; Figure 5 Structure-phase delay mapping in the design method for metasurface non-interlaced polarization multiplexing holographic display devices provided in this embodiment of the invention; Figure 6 These are the analytical parameters in the design method for a metasurface non-interlaced polarization multiplexing holographic display device provided in the embodiments of the present invention; Figure 7 The illustration shows the application effect of the design method for metasurface non-interlaced polarization multiplexing holographic display device provided in the embodiments of the present invention. Figure 8 This is a schematic diagram of the design system for a metasurface non-interlaced polarization multiplexing holographic display device provided in an embodiment of the present invention; Figure 9 A schematic block diagram of a processing terminal provided in an embodiment of the present invention; Figure 10 This is a schematic block diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0011] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0013] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0014] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0015] Please see Figure 1 As shown in the figure, an embodiment of this invention provides a design method for a metasurface non-interlaced polarization multiplexing holographic display device. This method is applied in a processing terminal 10 and is executed by application software installed in the processing terminal 10. Figure 2 As shown, the processing terminal 10 is communicatively connected to the transmitter 1 and the analyzer 2 to transmit data information. The metasurface device 3 is disposed between the transmitter 1 and the analyzer 2, with the microstructure layer in the metasurface device 3 facing the analyzer 2. Figure 2 As shown, the transmitter 1, the metasurface device 3, and the analyzer 2 are arranged sequentially along the same optical axis. The transmitter 1 can be an array light source with adjustable polarization direction. The array light source is used to project incident light corresponding to the incident polarized light signal. The incident light enters the metasurface device 3 and is modulated by the metasurface device 3 to output corresponding modulated light. The analyzer 2 can analyze the modulated light to obtain the corresponding outgoing polarized light signal. The modulated light is then used for imaging to obtain the displayed image. The processing terminal 10 analyzes and processes the incident and outgoing polarized light signals to obtain the corresponding metasurface device design information. Based on this metasurface device design information, the metasurface device can be designed accordingly, thereby obtaining a holographic display device capable of independent phase modulation of three arbitrary polarization states. The processing terminal 10 can be a terminal device with image analysis and data processing functions, such as a laptop, desktop computer, tablet computer, or mobile phone. Figure 1 As shown, the method includes steps S110 to S160.

[0016] S110. Perform phase analysis on the initial polarization signal obtained by the analyzer according to the preset phase recovery algorithm to obtain the corresponding phase analysis information.

[0017] Phase analysis can be performed on the initial polarization signal obtained by the analyzer using a phase retrieval algorithm. This initial polarization signal includes image polarization signals corresponding to at least three optical signal images with different polarization states. Optical signal images with different polarization states are projected onto a metasurface device and polarized with the same polarization state as the incident optical signal image to obtain the corresponding image polarization signal. The metasurface device used here is an initial device that has not been finely adjusted according to design information. After each optical signal image with a polarization state is modulated by the metasurface device, a set of image polarization signals corresponding to that polarization state is obtained. The combination of image polarization signals with multiple polarization states forms the initial polarization signal. By performing phase analysis on the image polarization signals of each polarization state in the initial polarization signal, the corresponding phase analysis information can be obtained.

[0018] In one specific embodiment of this application, such as Figure 2 As shown, the metasurface device can be illuminated using optical signal images with three polarization states. The optical signal image corresponding to the letter "Z" represents "horizontal polarization," the optical signal image corresponding to the letter "J" represents "45° polarization," and the optical signal image corresponding to the letter "U" represents "left-handed circular polarization." By performing polarization analysis on the modulated light obtained after modulation using the same polarization state as the incident light, the corresponding image polarization analysis signal can be obtained. This modulated light displays three different letters, "Z," "J," and "U," at the target plane. In this embodiment, the operating wavelength of the metasurface device is set to 632 nm. For this operating wavelength, the material of the substrate layer 31 in the metasurface device is SiO2, and the material of the microstructure 32 is TiO2. The structural positional relationship between the substrate layer 31 and the microstructure 32 is as follows: Figure 4 As shown.

[0019] In a specific embodiment, the phase resolution information includes the target phase distribution corresponding to each polarization state. Step S110 includes the following sub-steps: constructing a complex amplitude distribution corresponding to the image polarization signal of each polarization state of the initial polarization detection signal based on the basic phase distribution; performing frequency domain transformation on the complex amplitude distribution of each polarization state to obtain the complex amplitude frequency domain distribution corresponding to each polarization state; correcting the complex amplitude frequency domain distribution of each polarization state according to the characteristic parameters of the metasurface device to obtain the corrected complex amplitude distribution corresponding to each polarization state; performing inverse transformation on each of the corrected complex amplitude distributions to obtain the spatial complex amplitude distribution corresponding to each polarization state; and performing modulus replacement on each of the spatial complex amplitude distributions to update... The updated complex amplitude distribution corresponding to each polarization state is obtained; it is determined whether the updated complex amplitude distribution and the corresponding complex amplitude distribution of each polarization state satisfy the convergence condition set in the phase recovery algorithm; if the updated complex amplitude distribution and the corresponding complex amplitude distribution of the polarization state satisfy the convergence condition, the phase part of the updated complex amplitude distribution is taken as the target phase distribution corresponding to the polarization state; if the updated complex amplitude distribution and the corresponding complex amplitude distribution of the polarization state do not satisfy the convergence condition, the updated complex amplitude distribution is taken as the complex amplitude distribution, and the process returns to the step of performing frequency domain transformation on the complex amplitude distribution of each polarization state to obtain the frequency domain distribution of the complex amplitude corresponding to each polarization state. Wherein, the frequency domain transformation is a Fourier transform, and the inverse transform is an inverse Fourier transform.

[0020] Phase resolution information includes the target phase distribution corresponding to each polarization state. In a specific embodiment, the target phase distribution corresponding to the three polarization states is as follows: Figure 3 As shown; where φ 1 , φ 2 , φ 3 These represent the phase angles corresponding to the three polarization states, while x and y correspond to the horizontal and vertical coordinate positions, respectively. The number of samples taken here is consistent with the number of microstructures contained in the microstructure layer of the metasurface device, which is 64×64.

[0021] Specifically, a complex amplitude distribution corresponding to the image polarization detection signal for each polarization state can be constructed based on the fundamental phase distribution. For each polarization state (horizontal polarization, 45° polarization, left-handed circular polarization), a fundamental phase distribution is assumed to exist, such as a phase distribution with all zeros. This fundamental phase distribution is then combined with the image polarization detection signal for a specific polarization state to construct the complex amplitude distribution corresponding to that polarization state. For example, the intensity distribution in the image polarization detection signal is set as follows: I m ( x , y The fundamental phase distribution is as follows: φ 0( x , yIf )=0, then the initial complex amplitude distribution obtained by combination is as shown in formula (1): (1); For each polarization state, a frequency domain transformation is performed on the complex amplitude distribution, such as using Fourier transform, to convert the complex amplitude distribution into the corresponding complex amplitude frequency domain distribution. U 1( u , v (where u is the frequency and v is the amplitude), that is U 1( u , v )=F{ U 0( x , y )}, where F represents the two-dimensional Fourier transform operation, and i is the imaginary unit in the complex number.

[0022] Furthermore, the frequency domain distribution of complex amplitude for each polarization state is corrected based on the characteristic parameters of the metasurface device. Specifically, the frequency domain distribution of complex amplitude can be corrected based on the characteristic parameters. U 1( u , v Constraints can be imposed. For example, if the spectral characteristics of a metasurface device are known to have a certain limited range based on its operating wavelength, the complex amplitude frequency domain distribution can be determined based on the limited range corresponding to the spectral characteristics. U 1( u , v Spectral components outside this range are set to 0 or corrected to obtain the corrected complex amplitude distribution. U 2( u , v ).

[0023] Furthermore, the modified complex amplitude distribution can be inversely transformed, for example, by using an inverse Fourier transform, to obtain the corresponding spatial complex amplitude distribution. (The text then repeats the last sentence about the modified complex amplitude distribution.) U 2( u , v Perform a two-dimensional inverse Fourier transform to obtain the updated spatial complex amplitude distribution. U 3( x , y ),Right now U 3( x , y )=F −1 { U 2( u , v )}.

[0024] Complex amplitude distribution in this spatial domain U 3( x , y In ) U 3(x , y The modulus of ) is replaced with the square root of the intensity in the corresponding image polarity detection signal, i.e., | U 4( x , y )|= Meanwhile, its phase component is preserved to obtain the updated complex amplitude distribution. U 4( x , y ), where "||" is the absolute value operator.

[0025] Determine whether the updated complex amplitude distribution of each polarization state satisfies the convergence condition set in the phase retrieval algorithm. For example, calculate the phase difference between the updated complex amplitude distribution and the original complex amplitude distribution (e.g., obtain the phase difference between the updated and original complex amplitude distributions at each position and calculate the average value as the corresponding phase difference), and determine whether the phase difference is less than the phase threshold set in the convergence condition. If the phase difference is less than the phase threshold, the convergence condition is satisfied; if the phase difference is not less than the phase threshold, the convergence condition is not satisfied. If the convergence condition is satisfied, the phase portion of the updated complex amplitude distribution is used as the corresponding target phase distribution. If the convergence condition is not satisfied, iterative update processing needs to continue. At this time, the currently obtained updated complex amplitude distribution can be used as the initial complex amplitude distribution, and the frequency domain transformation steps described above are returned to be executed, thereby re-executing the phase update processing flow described above.

[0026] The above steps highlight the specific processing procedure for obtaining a set of target phase distributions by performing phase analysis on the image polarization detection signal of a certain polarization state. By performing phase analysis on the image polarization detection signal of each polarization state using the above method, the target phase distribution corresponding to each polarization state can be obtained.

[0027] S120: Receive the incident polarized light signal from the transmitter and the outgoing polarized light signal from the analyzer, and construct the corresponding outgoing light complex amplitude.

[0028] The transmitter emits incident light to the metasurface device based on the incident polarized light signal. The incident polarized light signal of the transmitter and the output polarized light signal of the analyzer can then be obtained. The complex amplitude of the output light can be constructed based on the incident polarized light signal and the output polarized light signal.

[0029] In a specific embodiment, step S120 includes the following sub-steps: constructing a corresponding incident polarization state matrix based on the incident polarized light signal; constructing a corresponding outgoing polarization state matrix based on the outgoing polarized light signal; and constructing the outgoing light complex amplitude based on the Jones matrix based on the incident polarization state matrix and the outgoing polarization state matrix.

[0030] The incident polarized light signal records the polarization state information of the incident light, and the emitted polarized light signal records the polarization state information of the emitted light; therefore, an incident polarization state matrix can be constructed based on the incident polarized light signal, and an emitted polarization state matrix can be constructed based on the emitted polarized light signal. For example, <α o β o | and |α i β i The incident polarization state matrices and the outgoing polarization state matrices are respectively the incident polarization state matrices and the outgoing polarization state matrices, which can be specifically expressed by formulas (2) and (3): (2); (3); In formula (2), the subscript is the letter 'o'. Further, based on the incident polarization state matrix and the outgoing polarization state matrix, the complex amplitude of the outgoing light is constructed using the Jones matrix, where the Jones matrix can be expressed by formula (4): (4); When incident light of different polarization states interacts with the microstructure, and the outgoing light undergoes specific polarization analysis, the complex amplitude of the outgoing light obtained by constructing the corresponding structure according to the Jones matrix method can be expressed by formula (5): (5).

[0031] S130. Analyze the complex amplitude of the emitted light according to the phase analysis information to obtain the analytical parameters corresponding to each position in the metasurface device.

[0032] Further, the complex amplitude of the emitted light obtained in the above steps is analyzed based on the phase analysis information to obtain the analytical parameters corresponding to each position in the metasurface device.

[0033] In a specific embodiment, step S130 includes the following sub-steps: expanding the complex amplitude of the emitted light to obtain the corresponding expanded formula of the complex amplitude of the emitted light; obtaining the phase expression of the emitted light corresponding to the expanded formula of the complex amplitude of the emitted light; and performing simultaneous analysis on the phase analysis information and the phase expression of the emitted light to obtain the analytical parameters corresponding to each position in the metasurface device.

[0034] The complete expression for the complex amplitude of the emitted light is shown in formula (6): (6); The Jones matrix can be specifically expressed by formula (7): (7); Where θ is the angle between the microstructure and the reference plane in the metasurface device, and this angle θ matches the anisotropic direction of the microstructure (for example, when the major axis of the microstructure has an angle with the reference axis, a rotation matrix is ​​used for alignment analysis); R(θ) is the rotation matrix used to describe the rotation of the coordinate system, where... , φ x , φ y Corresponding to x and y Phase delay in direction.

[0035] Expanding the complex exponent in the above-mentioned complex amplitude of the emitted light yields the corresponding expansion of the complex amplitude of the emitted light. For example, if the complex exponent is , it can be expanded to cos φ x +isin φ x Then, the complex exponents in formula (7) can all be expanded in a similar way, and then like terms are combined and the real part Re( E o ) and imaginary part Im( E o ),get: E o =Re( E o )+ i ⋅Im( E o By doing so, we can obtain the expansion formula of the complex amplitude of the emitted light corresponding to the complex amplitude of the emitted light.

[0036] Based on the above complex amplitude expansion of the emitted light, the phase expression of the emitted light is further obtained, complex number E o Argument φ o (i.e., the phase of the emitted light) satisfies: φ o = arg(E o =arctan This formula is the phase expression for the emitted light. When obtaining the phase expression for the emitted light, it is important to determine the quadrant; if Re( E o If )>0, directly use arctan(Im / Re); if Re( E o If ) < 0, then it needs to be added π Correction; if Re( E o If )=0, then it is π / 2 or 3 π / 2 (determined according to the correspondence between the positive and negative imaginary parts). φo The physical meaning of phase is: φ o It describes the "time delay" or "spatial phase distribution" of the outgoing light vibration, reflecting the phase modulation of the light field by the metasurface (such as the phase singularity of vortex light, wavefront modulation of holographic imaging, etc.).

[0037] By simultaneously analyzing the phase resolution information and the emitted light phase expression, the analytical parameters corresponding to each location in the metasurface device can be obtained. Specifically, the phase resolution information includes the target phase distribution corresponding to at least three polarization states, and the emitted light phase expression includes... φ x , φ x Given the three unknowns—including the rotation angle θ—these unknowns can be analyzed by simultaneously solving the equations for the phase distributions of at least three targets and the phase of the emitted light. This allows us to obtain the microstructure required for each location (with x and y as the horizontal and vertical coordinates) within the metasurface device. φ x , φ x The phase delay (where the subscript x represents the x-axis polarization direction and the subscript y represents the y-axis polarization direction) and the rotation angle θ are used as analytical parameters for the metasurface device. The obtained analytical parameters are as follows: Figure 6 As shown.

[0038] S140. Construct the corresponding structure-phase delay mapping based on the scanning information obtained from scanning the rectangular microstructure.

[0039] The length and width of the rectangular microstructure are scanned to obtain the corresponding scanning information; and a structure-phase delay mapping is constructed based on the scanning information to reflect the phase delay of microstructures with different geometric dimensions under x and y polarization.

[0040] In a specific embodiment, step S140 includes the following sub-steps: performing analytical calculations using the finite-difference time-domain method based on the characteristic parameters of the metasurface device and the scanning information to obtain the corresponding phase response; and performing position matching mapping based on the structural parameters in the scanning information and the phase response to construct the corresponding structure-phase delay mapping based on the same position.

[0041] In addition to the operating wavelength, the characteristic parameters of metasurface devices also include height H and period P. With a fixed height H and period P in a rectangular microstructure, the finite-difference time-domain (FDTD) method can be used to analytically calculate these characteristic parameters and the obtained scanning information, thereby obtaining the corresponding phase response. For example, the height H can be set to 700 nm, and the period P can be set to 400 nm.

[0042] In one specific embodiment, based on a fixed H and period P, the scanning rectangular microstructure has a length range L of 100-400 nm and a width range W of 100-400 nm. The phase responses corresponding to L and W are calculated using the finite-difference time-domain method. φ xreal and φ yreal Empirical formulas (such as quadratic functions) can be obtained by fitting using the finite-difference time-domain method, as follows: φ xreal =a 1 L²+b 1 L+c 1 W²+d 1 W+e 1 ; φ yreal =a 2 L²+b 2 L+c 2 W²+d 2 W+e 2 .in, a 1 、b 1 、 c 1 … e 2 All of these are coefficient values ​​in the fitting formula, and the coefficient values ​​vary with the material of the microstructure, the working wavelength, and the height H.

[0043] Based on the structural parameters at the same location in the scan information and the corresponding phase response at that location, a position matching mapping is performed to construct a structure-phase delay mapping based on the corresponding locations. The obtained structure-phase delay mapping is as follows: Figure 5 As shown.

[0044] S150. Match and map the parsing parameters according to the preset mapping rules and the structure-phase delay mapping to obtain the corresponding mapping information.

[0045] Based on the mapping rules and the structure-phase delay mapping obtained from the above steps, the analytical parameters are matched and mapped to obtain the mapping information corresponding to the analytical parameters.

[0046] In a specific embodiment, step S150 includes the following sub-steps: constructing an error function corresponding to the analytical parameters and the structure-phase delay mapping according to the mapping rules; when the error value of the error function is minimized according to the analytical parameters, the microstructure parameters corresponding to the structure-phase delay mapping are used as the mapping information.

[0047] Specifically, an error function corresponding to the parsed parameters and structure-phase delay mapping can be constructed based on the mapping rules. For example, the error function can be set as FOM=min[∑(| φ xreal - φ x |+| φ yreal - φ y |)], where FOM is the error value calculated based on the error function, and ∑ is the cumulative calculation symbol. φ xreal This represents the true phase response corresponding to different positions and the x-axis polarization direction in the structure-phase delay map. φ yreal This represents the true phase response corresponding to different positions and the y-axis polarization direction in the structure-phase delay map. φ x To analyze the required phase response corresponding to different positions in the parameters and the x-axis polarization direction, φ y To analyze the required phase response corresponding to different positions in the parameters and the y-axis polarization direction.

[0048] When the error function is obtained by taking the minimum error value according to the required phase response at each position in the analytical parameters, the structure-phase delay is mapped to the microstructure parameters at the corresponding positions as mapping information; then the mapping information includes the microstructure size corresponding to each microstructure (for example, in the specific embodiment, the microstructure layer is set to contain a total of 64×64 microstructures).

[0049] S160. Based on the mapping information, restore the microstructure geometric parameters of each position in the metasurface device to obtain the corresponding metasurface device design information.

[0050] Based on the microstructure dimensions in the mapping information, the microstructure geometric parameters at each location in the metasurface device are reconstructed, thereby obtaining the metasurface device design information containing the microstructure geometric parameters at each location. This design information is then used to construct the geometry of the entire microstructure layer. Based on this metasurface device design information, metasurface devices that meet the corresponding control requirements can be actually manufactured, enabling independent phase control of three arbitrary polarization states. Specifically, independent phase control can be performed on three arbitrary polarizations (such as horizontal polarization, 45° polarization, and left-handed circular polarization), thereby achieving holographic display functions with different patterns.

[0051] In one specific embodiment, a metasurface device is fabricated based on the obtained metasurface device design information, and the pattern obtained in the far field under a specified polarization combination is as follows: Figure 7 As shown; by Figure 7 It can be seen that all three letters are clearly displayed and there is no crosstalk between them, proving the reliability and practical application effect of the above design method. The metasurface device designed by the above method is applicable to multiple wavelengths, including ultraviolet, visible, near-infrared, and mid-infrared.

[0052] The design method for a metasurface non-interlaced polarization multiplexing holographic display device disclosed in the above embodiments involves: performing phase analysis on the initial polarization detection signal using a phase retrieval algorithm to obtain phase analysis information; receiving the incident and outgoing polarized light signals to construct the complex amplitude of the outgoing light and combining it with the phase analysis information to obtain the analytical parameters corresponding to each position in the metasurface device; constructing a corresponding structure-phase delay mapping based on the scanning information obtained from scanning and further matching the analytical parameters to obtain the corresponding mapping information; and reconstructing the microstructure geometric parameters at each position in the metasurface device based on the mapping information to obtain the metasurface device design information. This design method can design a holographic display device that enables independent phase modulation of three arbitrary polarization states, overcoming the limitation that non-interlaced metasurfaces can only modulate orthogonal polarization states; and it can achieve high spatial resolution display imaging and a larger imaging field of view.

[0053] This invention also provides a design system for metasurface non-interlaced polarization multiplexing holographic display devices, such as... Figure 8 As shown, the design system includes a processing terminal 10, a transmitter 1, and an analyzer 2. The processing terminal 10 is communicatively connected to both the transmitter 1 and the analyzer 2 to transmit data. A metasurface device 3 is disposed between the transmitter 1 and the analyzer 2, and the transmitter 1, the metasurface device 3, and the analyzer 2 are arranged sequentially along the same optical axis. The microstructure layer in the metasurface device 3 faces the analyzer 2. The processing terminal 10 is used to execute any embodiment of the aforementioned design method for a metasurface non-interlaced polarization multiplexing holographic display device. Specifically, please refer to... Figure 2 and Figure 4 , Figure 2 This is a schematic diagram illustrating an application scenario of the design method for a metasurface non-interlaced polarization multiplexing holographic display device provided in an embodiment of the present invention. Figure 4 A schematic diagram of the rectangular microstructure provided in an embodiment of the present invention.

[0054] Specifically, the metasurface device 3 consists of a substrate layer 31 and a microstructure 32. The substrate layer can be made of a material that is completely transmissive to the operating wavelength, with a refractive index lower than that of the microstructure material. The thickness of the substrate can be adjusted according to specific requirements, and can be any value from 0.2 mm to 3 mm. The microstructure 32 contains a microstructure layer, which is composed of multiple microstructures arranged in a matrix. The phase distribution of the metasurface can be changed by the type, size, and arrangement of the microstructures, with a phase variation range of 0-2π. There are gaps between the microstructures in the microstructure layer, which can be filled with a material with a refractive index lower than that of the microstructure to protect it. The microstructure material can be amorphous silicon, polycrystalline silicon, silicon nitride, titanium dioxide, gallium nitride, or chalcogenides, depending on the operating wavelength.

[0055] The microstructures in the microstructure layer can be either nano-rectangular pillars or nano-rectangular pores, and the arrangement of the microstructures can be periodic structures such as tetragonal arrangement and hexagonal arrangement or other quasicrystalline arrangement.

[0056] like Figure 9 As shown, the processing terminal 10 is specifically configured with the following units: a phase analysis unit 110, used to perform phase analysis on the initial polarization signal obtained by the analyzer according to a preset phase recovery algorithm to obtain corresponding phase analysis information, wherein the initial polarization signal includes image polarization signals corresponding to at least three optical signal images with different polarization states; a construction unit 120, used to receive the incident polarized light signal from the transmitter and the outgoing polarized light signal from the analyzer and construct the corresponding outgoing light complex amplitude; an analysis parameter acquisition unit 130, used to analyze the outgoing light complex amplitude according to the phase analysis information to obtain the analysis parameters corresponding to each position in the metasurface device; a mapping construction unit 140, used to construct the corresponding structure-phase delay mapping according to the scanning information obtained by scanning the rectangular microstructure; a matching mapping unit 150, used to match and map the analysis parameters according to the preset mapping rules and the structure-phase delay mapping to obtain the corresponding mapping information; and a parameter restoration unit 160, used to restore the microstructure geometric parameters at each position in the metasurface device according to the mapping information to obtain the corresponding metasurface device design information.

[0057] In a more specific embodiment, the microstructure layer in the metasurface device is composed of a microstructure array; the gaps between the microstructure arrays are protected by a filling material, the refractive index of which is lower than that of the microstructure array material; the material of the microstructure array is amorphous silicon, polycrystalline silicon, silicon nitride, titanium dioxide, gallium nitride, or a chalcogenide compound.

[0058] The design system for a metasurface non-interlaced polarization multiplexing holographic display device provided in this embodiment of the invention applies the aforementioned design method for a metasurface non-interlaced polarization multiplexing holographic display device. Phase analysis is performed on the initial polarization detection signal using a phase retrieval algorithm to obtain phase analysis information. The incident and outgoing polarized light signals are received to construct the complex amplitude of the outgoing light, and combined with the phase analysis information, the analytical parameters corresponding to each position in the metasurface device are obtained. Based on the scanning information obtained from the scan, a corresponding structure-phase delay mapping is constructed, and the analytical parameters are further matched and mapped to obtain the corresponding mapping information. The microstructure geometric parameters at each position in the metasurface device are reconstructed based on the mapping information to obtain the metasurface device design information. This design method can design a holographic display device that enables independent phase modulation of three arbitrary polarization states, breaking through the limitation that non-interlaced metasurfaces can only modulate orthogonal polarization states; and it can achieve high spatial resolution display imaging and a larger imaging field of view.

[0059] The virtual unit configured in the aforementioned processing terminal 10 can be implemented in the form of a computer program, which can be used in, for example... Figure 10 It runs on the computer device shown.

[0060] Please see Figure 10 , Figure 10 This is a schematic block diagram of a computer device provided in an embodiment of the present invention. The computer device may be a processing terminal 10 used to execute the design of a metasurface non-interlaced polarization multiplexed holographic display device to parse and obtain metasurface device design information.

[0061] See Figure 10 The computer device 500 includes a processor 502, a memory, and a communication interface 505 connected via a communication bus 501. The memory may include a storage medium 503 and internal memory 504.

[0062] The storage medium 503 may store an operating system 5031 and a computer program 5032. When the computer program 5032 is executed, it causes the processor 502 to execute a design method for a metasurface non-interlaced polarization multiplexed holographic display device, wherein the storage medium 503 may be a volatile storage medium or a non-volatile storage medium.

[0063] The processor 502 provides computing and control capabilities to support the operation of the entire computer device 500.

[0064] The internal memory 504 provides an environment for the operation of the computer program 5032 in the storage medium 503. When the computer program 5032 is executed by the processor 502, the processor 502 can execute a design method for a metasurface non-interlaced polarization multiplexed holographic display device.

[0065] This communication interface 505 is used for network communication, such as providing data transmission. Those skilled in the art will understand that... Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the computer device 500 to which the present invention is applied. The specific computer device 500 may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0066] The processor 502 is used to run the computer program 5032 stored in the memory to implement the corresponding functions in the above-described design method for metasurface non-interlaced polarization multiplexing holographic display devices.

[0067] Those skilled in the art will understand that Figure 10 The embodiments of the computer device shown do not constitute a limitation on the specific configuration of the computer device. In other embodiments, the computer device may include more or fewer components than illustrated, or combine certain components, or have different component arrangements. For example, in some embodiments, the computer device may include only memory and a processor. In such embodiments, the structure and function of the memory and processor are different from those shown. Figure 10 The embodiments shown are consistent and will not be described again here.

[0068] It should be understood that, in this embodiment of the invention, the processor 502 may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0069] In another embodiment of the invention, a computer-readable storage medium is provided. This computer-readable storage medium may be volatile or non-volatile. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps included in the above-described design method for a metasurface non-interlaced polarization multiplexing holographic display device.

[0070] Those skilled in the art will readily understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the foregoing description. Whether these functions are implemented in hardware or software 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 this invention.

[0071] In the embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Units with the same function may be grouped into one unit. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, or it may be an electrical, mechanical, or other form of connection.

[0072] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0073] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0074] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a computer-readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned computer-readable storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), magnetic disks, or optical disks.

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A design method for a metasurface non-interlaced polarization multiplexing holographic display device, characterized in that, The design method is applied to the processing terminal of the design system. The processing terminal is communicatively connected to both the transmitter and the analyzer to transmit data. A metasurface device is disposed between the transmitter and the analyzer, with the microstructure layer of the metasurface device facing the analyzer. The design method includes: The initial polarization signal obtained by the analyzer is phase-analyzed according to a preset phase recovery algorithm to obtain the corresponding phase analysis information. The initial polarization signal includes image polarization signals corresponding to at least three optical signal images with different polarization states. Receive the incident polarized light signal from the transmitter and the outgoing polarized light signal from the analyzer, and construct the corresponding complex amplitude of the outgoing light; The complex amplitude of the emitted light is analyzed based on the phase analysis information to obtain the analytical parameters corresponding to each position in the metasurface device; The corresponding structure-phase delay map is constructed based on the scanning information obtained from scanning the rectangular microstructure; The parsing parameters are matched and mapped according to the preset mapping rules and the structure-phase delay mapping to obtain the corresponding mapping information; Based on the mapping information, the microstructure geometric parameters at each location in the metasurface device are reconstructed to obtain the corresponding metasurface device design information.

2. The design method for a metasurface non-interlaced polarization multiplexing holographic display device according to claim 1, characterized in that, The phase resolution information includes the target phase distribution corresponding to each polarization state; the step of performing phase resolution on the initial polarization signal obtained by the analyzer according to a preset phase recovery algorithm to obtain the corresponding phase resolution information includes: Based on the basic phase distribution, construct the complex amplitude distribution corresponding to the image polarization signal of each polarization state of the initial polarization signal; The frequency domain transformation of the complex amplitude distribution of each polarization state is performed to obtain the frequency domain distribution of the complex amplitude corresponding to each polarization state; The frequency domain distribution of complex amplitude of each polarization state is corrected according to the characteristic parameters of the metasurface device to obtain the corrected complex amplitude distribution corresponding to each polarization state; By performing an inverse transformation on each of the modified complex amplitude distributions, the spatial complex amplitude distributions corresponding to each polarization state are obtained; The modulus of each of the spatial complex amplitude distributions is replaced to update the complex amplitude distribution corresponding to each polarization state; Determine whether the updated complex amplitude distribution of each polarization state and the corresponding complex amplitude distribution satisfy the convergence condition set in the phase recovery algorithm; If the updated complex amplitude distribution of the polarization state and the corresponding complex amplitude distribution satisfy the convergence condition, the phase portion of the updated complex amplitude distribution is taken as the target phase distribution corresponding to the polarization state; If the updated complex amplitude distribution of the polarization state does not satisfy the convergence condition with the corresponding complex amplitude distribution, the updated complex amplitude distribution is taken as the complex amplitude distribution, and the process returns to the step of performing frequency domain transformation on the complex amplitude distribution of each polarization state to obtain the frequency domain distribution of the complex amplitude corresponding to each polarization state.

3. The design method for a metasurface non-interlaced polarization multiplexing holographic display device according to claim 2, characterized in that, The frequency domain transform is a Fourier transform, and the inverse transform is an inverse Fourier transform.

4. The design method for a metasurface non-interlaced polarization multiplexing holographic display device according to any one of claims 1-3, characterized in that, The step of receiving the incident polarized light signal from the transmitter and the outgoing polarized light signal from the analyzer and constructing the corresponding outgoing light complex amplitude includes: Construct the corresponding incident polarization state matrix based on the incident polarized light signal; Construct the corresponding outgoing polarization state matrix based on the outgoing polarized light signal; The complex amplitude of the outgoing light is constructed based on the incident polarization state matrix and the outgoing polarization state matrix.

5. The design method for a metasurface non-interlaced polarization multiplexing holographic display device according to any one of claims 1-3, characterized in that, The step of resolving the complex amplitude of the emitted light based on the phase resolution information to obtain the analytical parameters corresponding to each position in the metasurface device includes: The complex amplitude of the emitted light is expanded to obtain the corresponding expanded formula of the complex amplitude of the emitted light; Obtain the phase expression of the emitted light corresponding to the complex amplitude expansion of the emitted light; By combining the phase analysis information with the phase expression of the emitted light, analytical parameters corresponding to each position in the metasurface device are obtained.

6. The design method for a metasurface non-interlaced polarization multiplexing holographic display device according to any one of claims 1-3, characterized in that, The step of constructing the corresponding structure-phase delay map based on the scanning information obtained from scanning the rectangular microstructure includes: The corresponding phase response is obtained by performing analytical calculations using the finite-difference time-domain method based on the characteristic parameters of the metasurface device and the scanning information. Based on the structural parameters in the scanning information and the phase response, a position matching mapping is performed to construct a corresponding structure-phase delay mapping based on the same position.

7. The design method for a metasurface non-interlaced polarization multiplexing holographic display device according to any one of claims 1-3, characterized in that, The step of matching and mapping the parsing parameters according to the preset mapping rules and the structure-phase delay mapping to obtain the corresponding mapping information includes: Construct an error function corresponding to the analytical parameters and the structure-phase delay mapping based on the mapping rules; When the error value of the error function is minimized according to the analytical parameters, the corresponding microstructure parameters in the structure-phase delay mapping are used as the mapping information.

8. A design system for a metasurface non-interlaced polarization multiplexing holographic display device, characterized in that, The design system includes a processing terminal, a transmitter, and an analyzer. The processing terminal is connected to the transmitter and the analyzer to transmit data information. The metasurface device is disposed between the transmitter and the analyzer, and the transmitter, the metasurface device, and the analyzer are arranged sequentially along the same optical axis. The microstructure layer in the metasurface device is oriented toward the polarizer; The processing terminal is used to execute the design method for a metasurface non-interlaced polarization multiplexing holographic display device as described in any one of claims 1-7.

9. The design system for a metasurface non-interlaced polarization multiplexing holographic display device according to claim 8, characterized in that, The system also includes a unit configured in the processing terminal: The phase analysis unit is used to perform phase analysis on the initial polarization signal obtained by the analyzer according to a preset phase recovery algorithm to obtain the corresponding phase analysis information. The initial polarization signal includes image polarization signals corresponding to at least three optical signal images with different polarization states. The construction unit is used to receive the incident polarized light signal from the transmitter and the outgoing polarized light signal from the analyzer and construct the corresponding outgoing light complex amplitude; The analytical parameter acquisition unit is used to analyze the complex amplitude of the emitted light according to the phase analysis information in order to obtain the analytical parameters corresponding to each position in the metasurface device. The mapping construction unit is used to construct the corresponding structure-phase delay mapping based on the scanning information obtained from scanning the rectangular microstructure; The matching and mapping unit is used to match and map the parsing parameters according to the preset mapping rules and the structure-phase delay mapping to obtain the corresponding mapping information; The parameter restoration unit is used to restore the microstructure geometric parameters of each position in the metasurface device according to the mapping information, so as to obtain the corresponding metasurface device design information.

10. The design system for a metasurface non-interlaced polarization multiplexing holographic display device according to claim 9, characterized in that, The microstructure layer in the metasurface device is composed of a microstructure array; The gaps between the microstructure arrays are protected by a filling material, the refractive index of which is lower than that of the microstructure array material; the material of the microstructure array is amorphous silicon, polycrystalline silicon, silicon nitride, titanium dioxide, gallium nitride, or a chalcogenide compound.

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