Metasurface and arbitrary visual information encryption transmission method and system
By designing metasurface structures and frequency-polarization-spatial multiplexing mechanisms, multi-channel holographic image generation and information encoding were realized, solving the problem of insufficient existing metasurface structure design, improving information capacity and security, and supporting the transmission of complex information.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-06
- Publication Date
- 2026-04-03
AI Technical Summary
Existing metasurface structures have many layers, few independent channels, small channel capacity, insufficient information transmission security, limited types of transmitted information, and high processing difficulty.
A metasurface structure is designed, comprising a first resonator, an intermediate body, an isolator, a cross-shaped metal component, an L-shaped metal component, and a square metal component. Six independent channels are formed through a frequency-polarization-spatial multiplexing mechanism to generate nine holographic images. The information is then encoded and decoded using the Gerschberg-Sachston algorithm.
It increases information capacity, supports multi-dimensional freedom of manipulation, improves information compatibility and security, can transmit any type of visual information, and has strong anti-hacking capabilities.
Smart Images
Figure CN121790773A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of communication technology, and in particular to a method and system for encrypted transmission of metasurface-based, arbitrary, and visual information. Background Technology
[0002] Existing metasurfaces use at least 6 layers and 2 to 3 materials to achieve 2 or 4 independent channels. Based on this, the main bottlenecks of existing metasurfaces are: (1) a large number of structural layers and few independent channels, and the design method of metasurfaces has not fully utilized their structural potential; (2) limited channel capacity, supporting only one or two degrees of freedom changes; (3) the use of multiple materials places higher demands on the processing environment and increases the difficulty of processing technology.
[0003] In recent years, terahertz (THz) communication technology based on electromagnetic metasurfaces has developed rapidly, but current information encryption transmission schemes still face the following problems: (1) Small information capacity: Generally, existing metasurface systems only support 4 independent channels and single-dimensional (such as polarization or frequency) control, which is difficult to meet the high capacity requirements. (2) Insufficient security of information transmission: Algorithm-based encryption is vulnerable to cracking by computing power and lacks physical layer security mechanisms; (3) Limited types of information to be transmitted: Currently, the types of information that can be transmitted are mainly simple numbers and text. The transmission of more complex characters (such as special symbols) and patterned information is relatively limited. Moreover, once the existing metasurface is processed, it can only transmit certain specific information, which lacks flexibility. Summary of the Invention
[0004] To address the aforementioned problems in the existing technology, this application provides a method and system for encrypted transmission of metasurface-based, arbitrary visual information.
[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a metasurface, comprising: a first resonator, an intermediate body, a spacer, a cross-shaped metal component, an L-shaped metal component, a square metal component, and a second resonator; The cross-shaped metal component, the isolator, and the L-shaped metal component are all disposed on one end face of the first resonator and the second resonator, and the center point of the cross-shaped metal component coincides with the center point of one end face of the first resonator and the second resonator, and the vertex of the L-shaped metal component coincides with the vertex of one end face of the first resonator or the second resonator; the isolator is disposed between the cross-shaped metal component and the L-shaped metal component. The square metal component and the L-shaped metal component are disposed on the other end face of the first resonator or the second resonator, and the center point of the square metal component coincides with the center point of the other end face of the first resonator or the second resonator, and the vertex of the L-shaped metal component coincides with the vertex of the other end face of the first resonator or the second resonator. The cross-shaped metal component and the square metal component disposed on one end face of the first resonator and the second resonator form a reflection channel for resonance; the L-shaped metal component disposed on one end face of the first resonator and the second resonator and the L-shaped metal component disposed on the other end face of the first resonator or the second resonator form a transmission channel for resonance. A frequency-polarization-space multiplexing mechanism is formed by changing the geometry of the cross-shaped metal component and the L-shaped metal component.
[0006] Secondly, this application provides a method for encrypted transmission of arbitrary visual information, including: Based on the Gerschberg-Sachston algorithm, using the frequency-polarization-spatial multiplexing mechanism for metasurface formation as described in any one of claims 1-3, six independent channels are realized, and nine holographic images are generated using the six independent channels; The nine holographic images are mapped to position codes, and the incident conditions required for holographic image imaging are mapped to information codes. The correspondence between incident condition parameters, holographic images, position codes, and information codes is established to form a transmitter coding library and a receiver coding library. The visual information of the target is mapped to obtain mapped data; The mapping data is encrypted using the sending end encoding library to obtain encrypted information; Based on the receiving end encoding library, the encrypted information is subjected to back-incidence conditions, the holographic image is recorded, the position encoding is obtained, and the inverse mapping operation is performed according to the mapping rules in the encryption encoding process to obtain the reconstruction result of the target information.
[0007] Thirdly, this application provides an arbitrary visual information encryption transmission system, comprising: The information encryption processing module is used to automatically acquire and map the visual information of the target to obtain mapping data, and to encrypt and encode the mapping data based on the sending end encoding library to obtain encrypted information; The terahertz signal transmission and control module is used to control the dual-frequency terahertz signal source to transmit terahertz waves of corresponding frequencies in sequence, while collimating the terahertz waves and converting them into pure linearly polarized waves polarized along a fixed direction. The metasurface imaging and information decryption module, based on the encrypted information and the receiver encoding library, sequentially incident terahertz waves with different parameters onto the metasurface, and uses two terahertz cameras to record the holographic images generated by the forward and backward incident terahertz waves respectively. The information reconstruction processing module is used to perform back-encoding on the holographic image and perform inverse mapping operation according to the mapping rules in the encryption encoding process to obtain the reconstruction result of the target information.
[0008] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a metasurface and a method and system for encrypted transmission of arbitrary visual information. By using resonance to form a reflection channel based on cross-shaped and square metal components disposed on one end face of a first and second resonator, and resonance to form a transmission channel based on L-shaped metal components disposed on one end face of the first and second resonators and on the other end face of the first or second resonator, six independent channels can be formed. This solves the problems of numerous structural layers, few independent channels, and the underutilization of the structural potential of metasurface structures. By changing the geometric dimensions of the cross-shaped and L-shaped metal components to form a frequency-polarization-spatial multiplexing mechanism, nine-frame holographic imaging can be achieved, increasing the controllable degrees of freedom from single to multi-dimensional, thus improving the information transmission capacity of the metasurface and solving the problem that existing metasurfaces only support changes in one or two degrees of freedom. By setting the first and second resonators to have the same structure, the requirements for the processing environment and technology can be reduced.
[0009] Furthermore, in this application, the encryption strategy is based on mapping the visual information of the target, which can support the encrypted transmission of any type of visual information (such as text, characters, complex graphics, QR codes, etc.). This breaks through the limitation of traditional schemes that are mostly limited to the transmission of simple numbers and text, and improves information compatibility and flexibility. Attached Figure Description
[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments 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.
[0011] Figure 1 This is a schematic diagram of the structure of a metasurface provided in an embodiment of this application; Figure 2 A flowchart illustrating an embodiment of this application provides a method for encrypting and transmitting arbitrary visual information. Figure 3 A schematic diagram of a holographic image provided in an embodiment of this application; Figure 4 This is a schematic diagram showing the dimensions of a cross resonator provided in one embodiment of this application; Figure 5 This is a schematic diagram showing the dimensions of an L-shaped resonator provided in one embodiment of this application; Figure 6 A schematic diagram of the reflection and transmission phases corresponding to 16 units provided in an embodiment of this application; Figure 7 A schematic diagram of mapping rules provided in an embodiment of this application; Figure 8 This is a schematic diagram of an encryption process provided in an embodiment of this application; Figure 9 This is a schematic diagram of the decryption process provided in an embodiment of this application; Figure 10 A schematic diagram illustrating the visualization of characters provided in one embodiment of this application; Figure 11 A schematic diagram illustrating the visualization of complex graphics provided in one embodiment of this application; Figure 12 A schematic diagram illustrating the implementation process of an arbitrary visual information encryption transmission method provided in an embodiment of this application; Figure 13 A functional module diagram of an arbitrary visual information encryption transmission system provided in an embodiment of this application; Figure 14 This is a schematic diagram illustrating the workflow of an arbitrary visual information encryption transmission system provided in one embodiment of this application. Detailed Implementation
[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0013] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0014] In one exemplary embodiment, this application provides a metasurface, such as Figure 1 As shown, the metasurface includes: a first resonator, an intermediate body, a spacer, a cross-shaped metal component, an L-shaped metal component, a square metal component, and a second resonator; like Figure 1part (a) and Figure 1 As shown in section (c), the cross-shaped metal component, the spacer, and the L-shaped metal component are all disposed on one end face of the first resonator and the second resonator, with the center point of the cross-shaped metal component coinciding with the center point of one end face of the first and second resonators, and the vertex of the L-shaped metal component coinciding with the vertex of one end face of the first or second resonator. The spacer is disposed between the cross-shaped metal component and the L-shaped metal component.
[0015] like Figure 1 As shown in part (d), a square metal component and an L-shaped metal component are disposed on the other end face of the first resonator or the second resonator, and the center point of the square metal component coincides with the center point on the other end face of the first resonator or the second resonator, and the vertex of the L-shaped metal component coincides with the vertex on the other end face of the first resonator or the second resonator.
[0016] A cross-shaped metal component and a square metal component, disposed on one end face of the first and second resonators, form a reflection channel for resonance. An L-shaped metal component, disposed on one end face of the first and second resonators, and an L-shaped metal component, disposed on the other end face of either the first or second resonator, form a transmission channel for resonance. The square metal component serves as the reflective base of the cross-shaped metal component, while the L-shaped metal component is designed to enhance transmission. The cross-shaped and L-shaped metal components control the modulation of reflection and transmission, respectively. The phase is controlled by the arm lengths of the cross-shaped and L-shaped metal components in the x and y directions. Figures 4-6 As shown, by changing the geometric dimensions (such as arm length) of the cross-shaped metal component and the L-shaped metal component, the resonance state of the structure can be changed, thereby indirectly changing the phase delay of the reflected wave and the transmitted wave, achieving the effect of phase modulation.
[0017] A frequency-polarization-space reuse mechanism is formed by changing the geometry of the cross-shaped and L-shaped metal components.
[0018] Based on the above description, the final side view of the metasurface is as follows: Figure 1 As shown in part (b).
[0019] In one exemplary embodiment of this application, in order to reduce crosstalk, such as Figure 1 part (a) and Figure 1 As shown in section (c), the spacer used in this application is a metal ring. A cross-shaped metal component is disposed inside the metal ring.
[0020] To further reduce the requirements for processing environment and processing technology, the materials used to prepare the first and second resonators in this application can both be polyimide.
[0021] In one exemplary embodiment of this application, this application also provides a method for encrypting and transmitting arbitrary visual information, such as... Figure 2 As shown, the method includes: Step 101: Based on the Gerchberg-Saxton algorithm, using the frequency-polarization-spatial multiplexing mechanism for metasurface formation provided above, six independent channels are implemented, and nine holographic images are generated using these six independent channels. For example, when x-polarized waves, y-polarized waves, and 45° linearly polarized waves are incident forward at a frequency of 1.46 THz, the reflected waves produce holographic images "2", "4", and "8". When incident backward at a frequency of 1.85 THz, the transmitted waves produce holographic images "1", "5", and "6". When incident backward at a frequency of 1.46 THz, the reflected waves produce holographic images "3", "7", and "9". Based on this, the nine holographic images formed are as follows: Figure 3 As shown.
[0022] Step 102: Assign the nine holographic images to the positional codes of the visualization information, and map the incident conditions required for holographic image imaging to information codes (unique). Establish the correspondence between the incident condition parameters, holographic images, position codes, and information codes, forming the transmitter coding library (as shown in Table 1) and the receiver coding library (as shown in Table 2). This step is mainly for constructing the coding system.
[0023] Table 1 Transmitter Encoding Library
[0024] Table 2 Receiver Encoding Library
[0025] Step 103: Map the visualization information of the target to obtain mapped data. For example, such as... Figure 8 As shown, the target's visualization information is mapped onto four sequentially arranged 3×3 pixel subarrays. The array sorting and mapping rules are as follows: Figure 7 As shown. During the mapping process, effective pixels of the visual information (i.e., pixels that visually constitute the image, equivalent to the main body) can be marked as black, and invalid pixels (i.e., pixels that visually have no effect on the composition of the image, equivalent to the background) can be marked as white, resulting in mapped data (i.e., a 3×3 pixel subarray labeled with colors). The fineness of the subarray division depends on the complexity of the target information.
[0026] Step 104: Encrypt the mapped data using the sending end encoding library to obtain encrypted information. The implementation process of this step may include: Step 104-1: Record the positions of all valid pixels in the visualized information within the mapped data, and encode the positions of the valid pixels into a digital holographic image according to the sending end encoding library, obtaining a string. For example, record the positions of all valid pixels in their respective 3×3 pixel subarrays as a string of numbers, and add a number representing the position of each pixel at the beginning of the string. n The value of , This indicates the total number of 3×3 pixel subarrays. The mapping data for each 3×3 pixel subarray is separated by a ".". After a complete visualization is mapped, it is separated from the next visualization by a " / ", resulting in a string. Then, according to the transmitter encoding library shown in Table 1, the positional codes in the string are mapped to the digital hologram.
[0027] Step 104-2: Based on the sender encoding library shown in Table 1, convert the numbers in the string into information encoding and send it as encrypted information to the receiver. The encrypted information does not contain the original information content; it is only a sequence of strings.
[0028] For example, such as Figure 8 As shown, taking user 1's (i.e., the sender's) "OK" as the target as an example, the encryption process is explained as follows: First, "O" is mapped to a pixel array and divided into four 3×3 subarrays. The black areas represent valid pixels, and the white areas represent invalid pixels. The position of each valid pixel (black) is recorded. The subarray mapping information is separated by ".", resulting in 358.158.26.24. Adding a symbol to the beginning of the string indicates... The value of 2 yields 2.358.158.26.24. The positional encoding of the valid pixels in the total string is converted to information encoding according to Table 1, resulting in 2.875.275.49.43. The character "K" is encoded using the same method, with "O" and "K" separated by a " / ", resulting in the string 2.875.275.49.43 / 2.4756.43.47.27. This string is then sent as encrypted information to user 2 (the receiver), thus completing the encryption process.
[0029] Step 105: Based on the receiver's encoding library, back-track the incident conditions of the encrypted information, record the holographic image, and perform an inverse mapping operation according to the mapping rules in the encryption encoding process to obtain the reconstructed target information. The implementation process of this step is as follows: After receiving the encrypted information, the receiver, based on the back-incident conditions in Table 2, sequentially incident all terahertz waves onto the metasurface, records the acquired holographic images, and then, according to the shared mapping rules (such as...),... Figure 7(As shown) The obtained number string is reverse mapped in the pixel array to restore the position of the effective pixels, thereby reconstructing the complete target information.
[0030] by Figure 9 Taking the character "OK" as an example, after receiving the encrypted information, User 2 (the receiver) deciphers the encrypted information back to the incident condition parameters, sequentially incidents terahertz waves onto the metasurface, and records the holographic image, which corresponds to the position code, resulting in 2.358.158.26.24. Using four 3×3 subarrays to form a pixel array, the position of each valid pixel in each subarray is reconstructed to restore the "O". The character "K" is decrypted in the same way, thus completing the decryption process.
[0031] Based on the above description, the arbitrary visualization information encryption transmission method provided in this application has at least the following advantages over the prior art: (1) Increased Information Transmission Capacity: This application employs a frequency-polarization-spatial multiplexing mechanism to realize nine holographic images, increasing the controllable degrees of freedom from single to multi-dimensional, thereby enhancing the information transmission capacity of the metasurface. Especially for QR code transmission, a single QR code can accommodate thousands of characters, which not only significantly increases resource utilization but also improves the information compression rate (information compression rate = (1- With a resolution of up to 99.95% (100% x 100%), the decoding process is simplified, requiring only scanning with a smart device.
[0032] (2) High information compatibility and flexibility: In this application, the encryption strategy is based on mapping information to a standardized pixel array, thus supporting the encrypted transmission of any type of visual information (text, characters, complex graphics, QR codes, etc., see reference). Figure 10 and Figure 11 This breaks through the limitations of traditional solutions, which are mostly limited to simple digital text transmission. For information transmission, the number of arrays can be flexibly selected according to the complexity. n The larger the array size, the higher the information pixel count, and the better the physical size of the jagged edges. Based on the formula: jagged edge height = pixel physical height × step pixel span, for the same canvas size, a 30×30 pixel image will have a jagged edge height of 3×3. This makes the image edges appear more continuous and smoother. Increasing the array size also improves the angular precision that can be represented. In a finite grid, a straight line can only be represented by a certain angular increment, and the minimum angular increment is related to the resolution. In a 3×3 grid, only a few angles can be clearly distinguished, such as 0° (horizontal), 45°, and 90° (vertical). In a 30×30 grid, much more complex angles such as arctan(1 / 10) ≈ 5.7° and arctan(2 / 7) ≈ 15.9° can be represented, significantly improving angular resolution and resulting in a more detailed image.
[0033] (3) Achieving dual encryption: This application combines information encoding (logic layer) and metasurface physical response (physical layer) dual encryption mechanisms, resulting in higher security. (See reference...) Figure 12 Encrypted information is transmitted in encoded form, and decryption relies on a physical imaging process bound to a specific metasurface structure. Even if the parameter sequence is intercepted, the original information cannot be deduced without shared metasurface design rules and an encoding mapping table. Taking the transmission of a QR code as an example, if the parameter sequence is intercepted and then a digital sequence is obtained through the metasurface, the total search space for complete decryption is the product of the encoding space and the mapping, which is 9! × 9! × 49! = 8e 73 If verifying one combination takes 1 nanosecond, then the cracking time would be as long as 8e. 61 The time taken is 2 seconds, which proves that this application has a strong resistance to cracking.
[0034] Based on the same inventive concept, this application also provides an embodiment for implementing the arbitrary visual information encrypted transmission system described above. The solution provided by this system is similar to the implementation scheme described in the above method; therefore, the specific limitations of one or more embodiments of the arbitrary visual information encrypted transmission system provided below can be found in the limitations of the arbitrary visual information encrypted transmission method described above, and will not be repeated here.
[0035] In one exemplary embodiment, such as Figure 13 As shown, an arbitrary visualization information encryption transmission system is provided: the system includes: an information encryption processing module, a terahertz signal transmission and control module, a holographic imaging and information decryption module, and an information reconstruction processing module.
[0036] The information encryption processing module is used to automatically acquire and map the visual information of the target to obtain the mapping data, and then encrypt and encode the mapping data based on the sending end encoding library to obtain encrypted information.
[0037] The terahertz signal transmission and control module is used to control the dual-frequency terahertz signal source to transmit terahertz waves of corresponding frequencies in sequence, while collimating the terahertz waves and converting them into pure linearly polarized waves polarized along a fixed direction.
[0038] The metasurface imaging and information decryption module, based on encrypted information and a receiver encoding library, sequentially incident terahertz waves with different parameters onto the metasurface, and uses two terahertz cameras to record the holographic images generated by the forward and backward incident terahertz waves, respectively.
[0039] The information reconstruction processing module is used to perform retrospective encoding on the holographic image and perform inverse mapping operation according to the mapping rules in the encryption encoding process to obtain the reconstruction result of the target information.
[0040] As an optional implementation method, such as Figure 14 As shown, the terahertz signal transmission and control module used in this application includes an electrically controllable dual-frequency terahertz signal source, a lens, an electrically controlled liquid crystal polarizer, and a beam splitter arranged sequentially along the terahertz signal transmission direction.
[0041] As an optional implementation, information encryption is primarily performed by a computer. The holographic imaging and information decryption module consists of a metasurface placed on an electrically rotating platform and two terahertz cameras. Information decryption is also performed by a computer.
[0042] As an optional implementation, the system provided in this application may further include a wire grid polarizer disposed between the electrically controlled liquid crystal polarizer and the beam splitter. For example... Figure 14 As shown, the computer that performs information encryption processing controls a dual-frequency terahertz signal source, an electronically controlled liquid crystal polarizer, and an electronically controlled rotating platform via an FPGA.
[0043] Based on the above description, the system workflow provided in this application is as follows: The target information is first encrypted on a computer using an encryption method, converting it into a transmittable information code corresponding to the incident wave parameters. A dual-frequency terahertz signal source sequentially emits terahertz waves of corresponding frequencies. These waves are collimated into plane waves by a lens, and then converted into the desired pure linearly polarized waves by a linear grating polarizer and an electro-hydraulic liquid crystal polarizer. These plane waves are then incident perpendicularly onto the metasurface via a beam splitter. The switching between front and rear incident modes is controlled by adjusting the rotation angle of an electrically controllable rotating platform. Imaging results are recorded at a preset focal plane using a terahertz camera and input into the computer. Finally, the target information is decrypted on the computer using a decryption method to reconstruct it.
[0044] In one exemplary embodiment, this application may also provide a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.
[0045] In one exemplary embodiment, this application may also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.
[0046] In one exemplary embodiment, this application may also provide a computer program product, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.
[0047] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.
[0048] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (RRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).
[0049] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.
[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0051] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A metasurface, characterized in that, include: First resonator, intermediate body, isolation component, cross-shaped metal component, L-shaped metal component, square metal component, and second resonator; The cross-shaped metal component, the isolator, and the L-shaped metal component are all disposed on one end face of the first resonator and the second resonator, and the center point of the cross-shaped metal component coincides with the center point of one end face of the first resonator and the second resonator, and the vertex of the L-shaped metal component coincides with the vertex of one end face of the first resonator or the second resonator; the isolator is disposed between the cross-shaped metal component and the L-shaped metal component. The square metal component and the L-shaped metal component are disposed on the other end face of the first resonator or the second resonator, and the center point of the square metal component coincides with the center point of the other end face of the first resonator or the second resonator, and the vertex of the L-shaped metal component coincides with the vertex of the other end face of the first resonator or the second resonator. The cross-shaped metal component and the square metal component disposed on one end face of the first resonator and the second resonator form a reflection channel for resonance; the L-shaped metal component disposed on one end face of the first resonator and the second resonator and the L-shaped metal component disposed on the other end face of the first resonator or the second resonator form a transmission channel for resonance. A frequency-polarization-space multiplexing mechanism is formed by changing the geometry of the cross-shaped metal component and the L-shaped metal component.
2. The metasurface according to claim 1, characterized in that, The spacer is a metal ring; the cross-shaped metal component is disposed inside the metal ring.
3. The metasurface according to claim 1, characterized in that, Both the first resonator and the second resonator are made of polyimide.
4. A method for encrypting and transmitting arbitrary visual information, characterized in that, include: Based on the Gerschberg-Sachston algorithm, using the frequency-polarization-spatial multiplexing mechanism for metasurface formation as described in any one of claims 1-3, six independent channels are realized, and nine holographic images are generated using the six independent channels; The nine holographic images are mapped to position codes, and the incident conditions required for holographic image imaging are mapped to information codes. The correspondence between incident condition parameters, holographic images, position codes, and information codes is established to form a transmitter coding library and a receiver coding library. The visual information of the target is mapped to obtain mapped data; The mapping data is encrypted using the sending end encoding library to obtain encrypted information; Based on the receiving end encoding library, the encrypted information is subjected to back-incidence conditions, the holographic image is recorded, the position encoding is obtained, and the inverse mapping operation is performed according to the mapping rules in the encryption encoding process to obtain the reconstruction result of the target information.
5. The method for encrypting and transmitting any visual information according to claim 4, characterized in that, The mapping data is encrypted using the aforementioned sending-end encoding library to obtain encrypted information, including: Record the position codes of all valid pixels in the visualization information, and obtain a string by mapping the position codes to the holographic image; Based on the aforementioned sending-end encoding library, the numbers in the string are converted into information encoding to obtain the encrypted information; the encrypted information is a set of strings corresponding to different incident conditions.
6. The method for encrypted transmission of any visualized information according to claim 5, characterized in that, Map the visual information of the target to an ordered sequence. In a 3×3 pixel subarray, valid pixels are marked as black and invalid pixels are marked as white. The position of each valid pixel in the subarray is the position code. This represents the total number of subarrays.
7. The method for encrypted transmission of any visual information according to claim 5, characterized in that, Based on the receiving end encoding library, the encrypted information is subjected to back-incidence conditions, a holographic image is recorded, a position code is obtained, and an inverse mapping operation is performed according to the mapping rules in the encryption encoding process to obtain the reconstruction result of the target information, including: According to the receiving end encoding library, all terahertz waves are sequentially incident onto the metasurface, and a holographic image is obtained based on the encrypted information; The holographic image is traced back to its positional encoding to obtain a string; According to the mapping rules in the encryption and encoding process, the string is reverse mapped in the pixel array to restore the effective pixel positions and obtain the reconstruction result of the target information.
8. An arbitrary visual information encryption transmission system, characterized in that, include: The information encryption processing module is used to automatically acquire and map the visual information of the target to obtain mapping data, and to encrypt and encode the mapping data based on the sending end encoding library to obtain encrypted information; The terahertz signal transmission and control module is used to control the dual-frequency terahertz signal source to transmit terahertz waves of corresponding frequencies in sequence, while collimating the terahertz waves and converting them into pure linearly polarized waves polarized along a fixed direction. The metasurface imaging and information decryption module, based on the encrypted information and the receiver encoding library, sequentially incident terahertz waves with different parameters onto the metasurface, and uses two terahertz cameras to record the holographic images generated by the forward and backward incident terahertz waves respectively. The information reconstruction processing module is used to perform back-encoding on the holographic image and perform inverse mapping operation according to the mapping rules in the encryption encoding process to obtain the reconstruction result of the target information.
9. The arbitrary visual information encryption transmission system according to claim 8, characterized in that, The signal transmission and control module includes a dual-frequency terahertz signal source, a lens, a wire grid polarizer, an electronically controlled liquid crystal polarizer, and a beam splitter arranged sequentially along the terahertz signal transmission direction.
10. The arbitrary visual information encryption transmission system according to claim 8, characterized in that, The metasurface and recording module also includes at least two terahertz cameras.