Active beam control device based on addressing-free metasurface and manufacturing method thereof

Abstract

The invention relates to the technical field of micro-nano optics, in particular to an active beam control device based on an addressing-free super-structure surface and a manufacturing method of the active beam control device. Comprising a metasurface array which is infiltrated in nematic liquid crystals and is formed by periodically arranging a plurality of nanostructures with different configurations; the nematic phase liquid crystal layer is used for dynamically regulating and controlling the environment refractive index through the azimuth angle change of liquid crystal molecules; wherein the metasurface array presents different phase gradients under different bias voltages, and the phase gradients meet a blazed grating equation, so that multi-angle wave beam control is realized. The active beam control design efficiency is high, the control precision is high, the universality is high, and the method has wide application prospects in the fields of wireless optical communication, radar and remote sensing, optical detection and distance measurement and the like.

Description

Technical Field

[0001] This application relates to the field of micro-nano optics technology, specifically to an active beam control device based on an address-free metasurface and its fabrication method. Background Technology

[0002] Active beam manipulation is a core technology in fields such as wireless optical communication, radar and remote sensing, and optical detection and ranging. Current technologies mainly rely on spatial light modulators (SLMs) or active metasurfaces. SLMs control phase through pixel-by-pixel addressing, but their pixel sizes are tens of micrometers, limiting the beam manipulation angle to the addressing resolution and making it difficult to achieve phase modulation units at the hundred-nanometer scale and large-angle control. Active metasurfaces also have the following problems: (1) It relies on micron-level addressing electrodes, requires complex overlay processes (such as layer-by-layer processing of electrodes and structures), has high manufacturing costs and poor stability (electrode crosstalk, sensitive to liquid crystal layer thickness). (2) The design requires simultaneous optimization of material parameters, unit structure, array arrangement and electrode excitation. The coupling of multiple parameters leads to low design efficiency. (3) The structural addressing period is in the micrometer range and the diffraction angle is limited, which cannot meet the requirements of high precision and large angle control.

[0003] In summary, existing active beam control methods suffer from limited diffraction angles, low control precision, and low versatility. Summary of the Invention

[0004] In view of this, embodiments of this application provide a knowledge distillation method, apparatus, electronic device, and storage medium to solve the problems of limited diffraction angle, low control accuracy, and low universality of existing active beam manipulation.

[0005] A first aspect of this application provides an active beam control device based on an address-free metasurface, comprising: Metasurface arrays, immersed in nematic liquid crystals, are composed of periodically arranged nanostructures of various configurations; Nematic liquid crystal layers are used to dynamically control the refractive index of the environment by changing the orientation angle of liquid crystal molecules. Under different bias voltages, the metasurface array exhibits different phase gradients, and the phase gradients satisfy the blazed grating equations to achieve multi-angle beam manipulation.

[0006] In one embodiment, the shape of the nanostructure includes a cuboid, a cylinder, a torus, and a cross.

[0007] In one embodiment, the ambient refractive index of the nematic liquid crystal layer is adjustable from 1.5 to 1.8, and the nematic liquid crystal molecules of all pixels have a uniform azimuth angle under voltage excitation.

[0008] A second aspect of this application provides a manufacturing method, including: Based on the simulation results of electromagnetic simulation software, an electromagnetic simulation database including actual phases is established. Based on the grating equation, the ideal phase corresponding to different diffraction angles is determined; A cost function is constructed based on the ideal phase and the actual phase, and iterative optimization is performed using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence. The compensation phase factor is dynamically updated using a particle swarm optimization algorithm, the ideal phase is corrected based on the compensation phase factor, and the result is fed back to a simulated annealing algorithm to iteratively optimize the nanostructure arrangement sequence. The metasurface array is fabricated based on the nanostructure arrangement sequence of the iterative output and immersed in a nematic liquid crystal to obtain an active beam control device.

[0009] In one embodiment, establishing an electromagnetic simulation database including actual phases based on the simulation results from electromagnetic simulation software includes: By adjusting the nanostructure size parameters and the azimuth angle of the liquid crystal molecules, the phase modulation amount under different nanostructure size parameters and different liquid crystal molecule azimuth angles is calculated using electromagnetic simulation software, and an electromagnetic simulation database including the nanostructure, refractive index distribution and actual phase correspondence is constructed.

[0010] In one embodiment, the step of constructing a cost function based on the ideal phase and the actual phase, and iteratively optimizing it using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence, includes: Constructing the cost function ; by With minimization as the objective, the simulated annealing algorithm is used for iterative optimization to determine the optimal nanostructure arrangement sequence; in, The phase difference between the ideal and actual wavefronts is represented by K, the number of target beam manipulation angles is represented by M, the upper limit of the nanostructure number is represented by m, and N represents the number corresponding to different beam manipulation angles. For ideal phase, This is the true phase.

[0011] In one embodiment, the step of dynamically updating the compensation phase factor using a particle swarm optimization algorithm, correcting the ideal phase based on the compensation phase factor, and feeding it back to a simulated annealing algorithm to iteratively optimize the nanostructure arrangement sequence includes: by Minimize the function using the particle swarm optimization algorithm. Optimization was performed to determine the compensation phase factor under different beam manipulation angles. ; Based on the determined compensation phase factor The ideal phase is corrected to obtain a new ideal phase. The process then returns to the step of constructing a cost function based on the ideal phase and the actual phase, and iteratively optimizing it using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence. in, For ideal phase, The true phase is represented by CS, which is the center spacing of the unit structure.

[0012] In one embodiment, adjusting the nanostructure size parameters includes: For cuboid nanostructures, adjust the length and / or width of the cuboid; For cylindrical nanostructures, adjust the cylinder diameter; For toroidal nanostructures, adjust the outer diameter and / or inner diameter of the toroid; For the cross-shaped nanostructure, at least one of the first short side, the second short side, the first long side, and the second long side of the cross is adjusted.

[0013] In one embodiment, the nanostructure is a 24-step structure.

[0014] In one embodiment, the height of the nanostructure is 190-210 nm and the center spacing of the unit structure is 350-370 nm.

[0015] The first aspect of this application provides an active beam control device based on an address-free metasurface, comprising a metasurface array immersed in a nematic liquid crystal, composed of a periodically arranged array of nanostructures with various configurations; a nematic liquid crystal layer for dynamically controlling the ambient refractive index by varying the azimuth angle of the liquid crystal molecules; wherein, under different bias voltages, the metasurface array exhibits different phase gradients, and the phase gradients satisfy the blazed grating equation to achieve multi-angle beam manipulation. An electromagnetic response database of the hybrid interaction between the metasurface and the nematic liquid crystal is constructed using electromagnetic simulation software, and a cost function is established by combining simulated annealing and particle swarm optimization algorithms. This allows for the selection of multi-step nanostructures with the smallest phase gradient difference from the ideal phase distribution wave under different liquid crystal molecule rotation angles (i.e., ambient refractive indexes). The metasurface array composed of the above structures, immersed in the nematic liquid crystal, can achieve active beam manipulation solely through an address-free overall bias voltage. This active beam control design is highly efficient, precise, and versatile, and has broad application prospects in fields such as wireless optical communication, radar and remote sensing, and optical detection and ranging.

[0016] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a nanostructure provided in an embodiment of this application; Figure 2 This is a schematic diagram of the preparation method of this application; Figure 3 This is a schematic diagram of four nanostructures provided in one embodiment of this application; Figure 4 This is a schematic diagram of the electromagnetic response library obtained from the simulation of this application; Figure 5 This is a flowchart illustrating the simulated annealing algorithm and particle swarm optimization algorithm used in this application; Figure 6 This is a graph showing the wavefront phase difference as a function of the number of particle swarm iterations in this application; Figure 7 This is a schematic diagram of the phase modulation amount of the nanostructure and the ideal phase difference in this application; Figure 8 This is a schematic diagram of the liquid crystal immersion metasurface array of this application; Figure 9 This is the far-field intensity distribution diagram obtained from Kirchhoff diffraction calculations in this application. Detailed Implementation

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0021] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0022] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0023] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0025] like Figure 1 As shown, this application provides an active beam control device based on an address-free metasurface, comprising: Metasurface arrays, immersed in nematic liquid crystals, are composed of periodically arranged nanostructures of various configurations; Nematic liquid crystal layers are used to dynamically control the refractive index of the environment by changing the orientation angle of liquid crystal molecules. Under different bias voltages, the metasurface array exhibits different phase gradients, and the phase gradients satisfy the blazed grating equations to achieve multi-angle beam manipulation.

[0026] This application embodiment constructs an electromagnetic response database of the hybrid interaction between metasurfaces and nematic liquid crystals based on electromagnetic simulation software. It then establishes a cost function using simulated annealing and particle swarm optimization algorithms to optimize the multi-step nanostructures that minimize the difference between the phase gradient and the ideal phase distribution wave under different liquid crystal molecule rotation angles (i.e., ambient refractive index). The metasurface array composed of these structures is immersed in nematic liquid crystals, enabling active beam manipulation using only an address-free overall bias voltage. This active beam manipulation design is highly efficient, precise, and versatile, showing broad application prospects in wireless optical communication, radar and remote sensing, optical detection and ranging, and other fields.

[0027] In one embodiment, the shape of the nanostructure includes a cuboid, a cylinder, a torus, and a cross.

[0028] In one embodiment, the ambient refractive index of the nematic liquid crystal layer is adjustable from 1.5 to 1.8, and the nematic liquid crystal molecules of all pixels have a uniform azimuth angle under voltage excitation.

[0029] In the application, the metasurface array consists of periodically arranged titanium dioxide 1, silicon dioxide 2, and silver nanostructures 3 (cubic prisms / cylinders / rings / crosses), with a height H=200 nm and a unit center spacing CS=360 nm.

[0030] In applications, nematic liquid crystal layers are used to wet metasurfaces. The azimuth angles of liquid crystal molecules in different pixels are synchronously controlled by a uniform applied voltage, thereby changing the environmental refractive index of the metasurface.

[0031] In one embodiment, the height of the nanostructure is 190-210 nm and the center spacing of the unit structure is 350-370 nm.

[0032] The working principle of the above-mentioned active beam control device is as follows: Voltage excitation → change in the azimuth angle of liquid crystal molecules → dynamic adjustment of the refractive index of the environment → change in the electromagnetic response (phase / amplitude) of the nanostructure → formation of a specific phase gradient → satisfaction of the blazed grating equation Beam control angles (e.g., θ=0°, 8.85°, 17.93°, 27.50°).

[0033] like Figure 2 As shown, a second aspect of this application provides a manufacturing method, including: Based on the simulation results of electromagnetic simulation software, an electromagnetic simulation database including actual phases is established. Based on the grating equation, the ideal phase corresponding to different diffraction angles is determined; A cost function is constructed based on the ideal phase and the actual phase, and iterative optimization is performed using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence. The compensation phase factor is dynamically updated using a particle swarm optimization algorithm, the ideal phase is corrected based on the compensation phase factor, and the result is fed back to a simulated annealing algorithm to iteratively optimize the nanostructure arrangement sequence. The metasurface array is fabricated based on the nanostructure arrangement sequence of the iterative output and immersed in a nematic liquid crystal to obtain an active beam control device.

[0034] In one embodiment, establishing an electromagnetic simulation database including actual phases based on the simulation results from electromagnetic simulation software includes: By adjusting the nanostructure size parameters and the azimuth angle of the liquid crystal molecules, the phase modulation amount under different nanostructure size parameters and different liquid crystal molecule azimuth angles is calculated using electromagnetic simulation software, and an electromagnetic simulation database including the nanostructure, refractive index distribution and actual phase correspondence is constructed.

[0035] In the application, after determining the working wavelength λ, electromagnetic simulation software such as FDTD and Comsol Multiphysics are used to calculate the phase / amplitude modulation of nanostructures with different configurations / sizes at 16 liquid crystal molecule rotation angles (corresponding to refractive indices of 1.5-1.8), and an electromagnetic response database containing 25,600 sets of data is established.

[0036] In one embodiment, adjusting the nanostructure size parameters includes: For cuboid nanostructures, adjusting the length of the cuboid... L and / or width W ; For cylindrical nanostructures, adjusting the cylinder diameter... D ; For toroidal nanostructures, adjust the outer diameter D1 and / or inner diameter D2 of the toroid; For the cross-shaped nanostructure, adjust the first short side of the cross. W 1. The second shorter side W 2. The first longer side L 1. The second longest side L At least one of 2.

[0037] The simulation variables also include: the rotation angle of nematic liquid crystal molecules.

[0038] In the application, an xyz rectangular coordinate system is established. The long side of the nanobrick unit structure represents the major axis, and the short side represents the minor axis. Φ is the angle between the major axis and the x-axis of the nanobrick unit structure, i.e., the orientation angle of the nanobrick unit structure (Φ ranges from 0° to 180°). The working wavelength is selected as 665 nm, the base side length CS is 380 nm, and the height H is 220 nm. The dimensional parameters of the nanobrick unit structure, including the length L and width W, are optimized using electromagnetic simulation software. Figure 1 As shown, the reflectivity and phase modulation of the nanostructure were obtained by varying the equivalent refractive index of the liquid crystal molecules from 1.5 to 1.8. Considering the required database size and computing resources, four shapes—cubic prism, cylinder, torus, and cross—were used as examples. Figure 3 As shown. The reflectivity and phase modulation of nanostructures of different sizes under different refractive indices were obtained, and a database of electromagnetic responses of unit structures was established (containing 800 sets of structures with intensity and phase modulation at 16 different refractive indices, totaling 25,600 data points). Figure 4 As shown in the figure. This database includes nanostructures, refractive index distributions, and actual phase correspondences.

[0039] In one embodiment, the step of constructing a cost function based on the ideal phase and the actual phase, and iteratively optimizing it using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence, includes: Constructing the cost function ; by With minimization as the objective, the simulated annealing algorithm is used for iterative optimization to determine the optimal nanostructure arrangement sequence; in, The phase difference between the ideal and actual wavefronts is represented by K, the number of target beam manipulation angles is represented by M, the upper limit of the nanostructure number is represented by m, and N represents the number corresponding to different beam manipulation angles. For ideal phase, This is the true phase.

[0040] In the application, a simulated annealing algorithm is used to establish a cost function, find the optimal array structure arrangement from the simulation database, and the mapping relationship between the optimal liquid crystal molecule rotation angle and the corresponding beam control angle, so as to minimize the difference between the ideal phase of beam control and the actual phase wavefront in the simulation database.

[0041] In one embodiment, the step of dynamically updating the compensation phase factor using a particle swarm optimization algorithm, correcting the ideal phase based on the compensation phase factor, and feeding it back to a simulated annealing algorithm to iteratively optimize the nanostructure arrangement sequence includes: by Minimize the function using the particle swarm optimization algorithm. Optimization was performed to determine the compensation phase factor under different beam manipulation angles. ; Based on the determined compensation phase factor The ideal phase is corrected to obtain a new ideal phase. The process then returns to the step of constructing a cost function based on the ideal phase and the actual phase, and iteratively optimizing it using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence. in, For ideal phase, The true phase is represented by CS, which is the center spacing of the unit structure.

[0042] In the application, a particle swarm optimization algorithm is used to establish the compensation phase factor under different beam manipulation angles. In order to obtain a new ideal phase This further reduces the difference between the ideal phase of beam manipulation and the actual phase wavefront in the simulation library without changing the phase gradient.

[0043] In one embodiment, the nanostructure is a 24-step structure.

[0044] In one embodiment, the simulated annealing algorithm and particle swarm optimization algorithm are described below using a 24-step nanostructure as an example.

[0045] Step 1: Determine the ideal phase corresponding to different diffraction angles based on the grating equation. Here, only four beam control angles under a 24-step structure are used as examples for illustration. This example is not a limitation of the invention; the design method covered by this invention is applicable to various numbers of steps and various beam control angles. When the phase gradients of the 24-step structure are 0 / 24CS, 4π / 24CS, 8π / 24CS, and 12π / 24CS, the required phase control amounts for different structures are: ; Where m is the serial number corresponding to different nanobricks (a total of 24 step structures were selected); N is the serial number corresponding to different beam manipulation angles (a total of 4 beam manipulation angles exist); CS is the center spacing of the unit structure. The ideal phase distribution corresponding to different beam control angles, i.e., the first... N The diffraction angle of the first m The ideal phase required for each nanostructure.

[0046] The corresponding beam control angle is: 4; Taking a working wavelength of λ=665 nm as an example, according to the above... The calculation formula can be obtained as follows: θ 1 = 0° θ 2 = 8.85° θ 3 = 17.93° θ 4 = 27.50°.

[0047] A simulated annealing algorithm is used to establish a cost function. The optimal array structure arrangement and the mapping relationship between the optimal liquid crystal molecule rotation angle and the corresponding beam manipulation angle are found from the simulation database to minimize the difference between the ideal phase of beam manipulation and the actual phase wavefront in the simulation database. .

[0048] Step 2: Using the particle swarm optimization algorithm, the compensation phase factor under different beam manipulation angles is established. In order to obtain a new ideal phase This further reduces the difference between the ideal phase for beam manipulation and the actual phase wavefront in the simulation library without altering the phase gradient. .

[0049] like Figure 5 As shown, the compensation phase factor determined by the particle swarm optimization algorithm This information is fed back to the simulated annealing algorithm to calculate the new ideal phase and initiate the next iteration of the simulated annealing algorithm. The iteration ends when the particle swarm optimization algorithm reaches a preset number of iterations. This embodiment combines the above-mentioned particle swarm optimization algorithm and simulated annealing algorithm to establish the compensation phase factor under different beam manipulation angles. New ideal phase 、 The rotation angle of nematic liquid crystal molecules and the shape, size, and arrangement of nanostructures under different beam control angles were investigated. An active beam control device was obtained by periodically arranging 24-step nanostructures into an array and immersing them in nematic liquid crystal. When linearly polarized light is incident, the azimuth angle of the liquid crystal molecules is changed by adjusting the applied voltage to the metasurface, thereby altering the refractive index of the metasurface environment. The optimized structure exhibits specific phase gradients under four different applied voltages, thus achieving beam control at different angles.

[0050] like Figure 6 As shown, after 600 iterations of optimization using the particle swarm optimization algorithm, the sum of the phase differences of the four wavefronts is 5.47. At each beam manipulation angle, the average phase difference per nanostructure is 5.47 / 4 / 24 = 0.057. Figure 7 As shown.

[0051] The optimized 24-step nanobrick unit structure has different excitation dispersions, which satisfies the phase gradient required for active beam manipulation at different positions: .

[0052] The selected 24-step structure is periodically repeated to form a metasurface array, such as... Figure 8 As shown, glass 4 is filled with nematic liquid crystal 5, and a metasurface array is immersed in the nematic liquid crystal 5. The ambient refractive indices are set to 1.78, 1.70, 1.58, and 1.66. The array phase plane is extracted, and the complex amplitude distribution of the wavefront in the far field is calculated based on Kirchhoff diffraction. ; In the formula, For the wavefront in coordinates ( x,y Complex amplitude distribution at point (). r This represents the distance from a point on the wavefront to the observation point. z Let z be the distance between the observation point and the metasurface array. Setting z to 1000 μm, the far-field intensity distribution calculated using the above formula is as follows: Figure 9 As shown, the designed metasurface array can achieve active beam manipulation under different environmental refractive indices.

[0053] This application embodiment applies a bias voltage to the entire metasurface array, eliminating the need to address individual cell structures. The advantages of this design are as follows: 1) No overlay process is required, which reduces the complex steps in the preparation process and lowers the requirements for equipment and technology; 2) No separate addressing electrodes are required, simplifying the device structure and reducing manufacturing costs; 3) The absence of crosstalk issues between different addressing units reduces the requirements for liquid crystal thickness and improves device stability and reliability. These three advantages combined significantly reduce the fabrication difficulty and cost of the device, making this invention more feasible and competitive in practical applications.

[0054] This application employs an address-free scheme, with the actual phase modulation unit being a metasurface structure unit with a period on the order of hundreds of nanometers. Compared to traditional beam control devices, this hundreds-of-nanometers-level structure unit can significantly increase the diffraction angle, improving the flexibility and precision of beam manipulation.

[0055] The optimization scheme adopted in this application has broad applicability and is not limited to liquid crystal immersion metasurfaces. It can be applied to the structural optimization of other active metasurfaces, providing an effective method and approach for the design of different types of metasurfaces.

[0056] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0057] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An active beam control device based on an address-free metasurface, characterized in that, include: Metasurface arrays, immersed in nematic liquid crystals, are composed of periodically arranged nanostructures of various configurations; Nematic liquid crystal layers are used to dynamically control the refractive index of the environment by changing the orientation angle of liquid crystal molecules. Under different bias voltages, the metasurface array exhibits different phase gradients, and the phase gradients satisfy the blazed grating equations to achieve multi-angle beam manipulation.

2. The active beam control device based on an address-free metasurface as described in claim 1, characterized in that, The shapes of the nanostructures include cuboids, cylinders, toroids, and crosses.

3. The active beam control device based on an address-free metasurface as described in claim 1, characterized in that, The ambient refractive index of the nematic liquid crystal layer is adjustable from 1.5 to 1.8, and the nematic liquid crystal molecules of all pixels have a uniform azimuth angle under voltage excitation.

4. A method for fabricating an active beam control device based on an address-free metasurface as described in any one of claims 1 to 3, characterized in that, include: Based on the simulation results of electromagnetic simulation software, an electromagnetic simulation database including actual phases is established. Based on the grating equation, the ideal phase corresponding to different diffraction angles is determined; A cost function is constructed based on the ideal phase and the actual phase, and iterative optimization is performed using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence. The compensation phase factor is dynamically updated using a particle swarm optimization algorithm, the ideal phase is corrected based on the compensation phase factor, and the result is fed back to a simulated annealing algorithm to iteratively optimize the nanostructure arrangement sequence. The metasurface array is fabricated based on the nanostructure arrangement sequence of the iterative output and immersed in a nematic liquid crystal to obtain an active beam control device.

5. The method as described in claim 4, characterized in that, The simulation results based on the electromagnetic simulation software are used to establish an electromagnetic simulation database that includes the actual phase, including: By adjusting the nanostructure size parameters and the azimuth angle of the liquid crystal molecules, the phase modulation amount under different nanostructure size parameters and different liquid crystal molecule azimuth angles is calculated using electromagnetic simulation software, and an electromagnetic simulation database including the nanostructure, refractive index distribution and actual phase correspondence is constructed.

6. The method as described in claim 4, characterized in that, The process of constructing a cost function based on the ideal and actual phases, and iteratively optimizing it using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence, includes: Constructing the cost function ; by With minimization as the objective, the simulated annealing algorithm is used for iterative optimization to determine the optimal nanostructure arrangement sequence; in, The phase difference between the ideal and actual wavefronts is represented by K, the number of target beam manipulation angles is represented by M, the upper limit of the nanostructure number is represented by m, and N represents the number corresponding to different beam manipulation angles. For ideal phase, This is the true phase.

7. The method as described in claim 4, characterized in that, The step of dynamically updating the compensation phase factor using a particle swarm optimization algorithm, correcting the ideal phase based on the compensation phase factor, and feeding it back to a simulated annealing algorithm to iteratively optimize the nanostructure arrangement sequence includes: by Minimize the function using the particle swarm optimization algorithm. Optimization was performed to determine the compensation phase factor under different beam manipulation angles. ; Based on the determined compensation phase factor The ideal phase is corrected to obtain a new ideal phase. The process then returns to the step of constructing a cost function based on the ideal phase and the actual phase, and iteratively optimizing it using a simulated annealing algorithm to determine the optimal nanostructure arrangement sequence. in, For ideal phase, The true phase is represented by CS, which is the center spacing of the unit structure.

8. The method as described in claim 5, characterized in that, The adjustment of nanostructure size parameters includes: For cuboid nanostructures, adjust the length and / or width of the cuboid; For cylindrical nanostructures, adjust the cylinder diameter; For toroidal nanostructures, adjust the outer diameter and / or inner diameter of the toroid; For the cross-shaped nanostructure, at least one of the first short side, the second short side, the first long side, and the second long side of the cross is adjusted.

9. The method as described in claim 4, characterized in that, The nanostructure has a 24-step structure.

10. The method as described in claim 4, characterized in that, The height of the nanostructure is 190~210 nm, and the spacing between the center of the unit structure is 350~370 nm.

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