Artificial surface wave and spatial wave wavefront modulation device based on heterogeneous metasurface

Abstract

The application relates to the technical field of electromagnetic regulation, in particular to a wave front regulation device for artificial surface waves and space waves based on a heterogeneous super surface. The device comprises a bottom metal reflection layer, a middle dielectric layer and a top metal composite structure. The bottom metal reflection layer is used for total reflection of incident electromagnetic waves and isolation of bottom electromagnetic interference. The middle dielectric layer is fixedly connected with the bottom metal reflection layer, and is used for phase regulation and waveguide transmission. The top metal composite structure is arranged on the upper surface of the middle dielectric layer, and is used for regulating the phase and amplitude of electromagnetic waves. The application can realize independent phase regulation of multiple frequencies and multiple polarizations, and can synchronously complete artificial surface wave excitation transmission and space wave regulation imaging, effectively avoiding unit crosstalk and frequency band interference, and has compact structure and high integration degree.

Description

Technical Field

[0001] This application relates to the field of electromagnetic control technology, and in particular to a wavefront control device for artificial surface waves and space waves based on heterogeneous metasurfaces. Background Technology

[0002] Space waves and artificial surface waves, as two fundamental forms of electromagnetic waves, occupy a core position in the field of modern photonics. Currently, the industry generally employs traditional optical manipulation schemes for wavefront control of space waves and artificial surface waves, relying primarily on conventional optical components such as lenses, prisms, phase waveplates, optical waveguides, and optoelectronic modulators to build the control system and achieve functionality. However, these traditional optical coupling control devices are inherently limited by their material properties, structural forms, and working principles, resulting in numerous unavoidable technical shortcomings. Not only are the overall devices bulky and cumbersome with low spatial integration, but they also generally suffer from fixed and singular operating modes and limited adaptability to various scenarios. This makes it difficult to align with the industry's development trends of miniaturization, integration, and multifunctionality, significantly restricting the widespread adoption and large-scale application of electromagnetic beam wavefront manipulation technology in various precision optoelectronic devices and integrated communication systems.

[0003] To overcome the limitations of traditional optical devices, two-dimensional artificial electromagnetic metasurfaces with subwavelength array configurations have emerged. These structures allow for precise design and control of the geometry, shape, and array arrangement of subwavelength functional units, enabling flexible manipulation of core electromagnetic parameters such as amplitude, phase, and polarization state of electromagnetic waves. They possess superior electromagnetic control performance unmatched by natural electromagnetic materials and are gradually being applied to research on wavefront manipulation of space waves and artificial surface waves. However, currently developed and applied functional metasurfaces still suffer from significant technical shortcomings. Most metasurface structures can only establish a small number of independent transmission and control channels, resulting in relatively limited electromagnetic wave control dimensions. They cannot simultaneously perform decentralized and diversified independent control of artificial surface waves and space waves, failing to meet the research and production needs of high-capacity, high-density integrated optoelectronic devices and hindering the further development of advanced technologies such as multi-channel parallel electromagnetic wave transmission and multi-dimensional optical field manipulation.

[0004] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0005] The main objective of this application is to propose a wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces. This device can perform multi-frequency and multi-polarization independent phase modulation and simultaneously complete artificial surface wave excitation and transmission and space wave modulation imaging. It effectively avoids unit crosstalk and frequency band interference, and has a compact structure and high integration.

[0006] To achieve the above objectives, one aspect of this application proposes a wavefront manipulation device for artificial surface waves and space waves based on heterogeneous metasurfaces, comprising: A bottom metal reflective layer is provided to totally reflect incident electromagnetic waves and isolate bottom electromagnetic interference. An intermediate dielectric layer is fixedly connected to the bottom metal reflective layer and is used for phase modulation. The intermediate dielectric layer includes a surface excitation region, a surface transmission region, and a spatial propagation region. Multiple first structural heterogeneous units are arrayed within the surface excitation region, a non-metallic structure is provided within the surface transmission region, and multiple second structural heterogeneous units are arrayed within the spatial propagation region. The first structural heterogeneous units include nested metal ring structures. By adjusting the rotation angle of each metal ring within the nested metal ring structure, complete 2π phase coverage of the artificial surface wave can be achieved at different operating frequencies. The second structural heterogeneous units include nested double-cross metal structures. By adjusting the major axis, minor axis, and rotation angle of the two sets of cross metal structures within the nested double-cross metal structure, complete 2π phase coverage of the artificial surface wave and the spatial wave can be achieved at different operating frequencies. A top metal composite structure is disposed on the upper surface of the intermediate dielectric layer, and the top metal composite structure is used to regulate the phase and amplitude of the artificial surface wave and the space wave.

[0007] In some embodiments, the array formed by a plurality of the first structural heterogeneous units is arranged with the length direction of the surface excitation region as the y-axis and the width direction as the x-axis, with the x-axis as the row and the y-axis as the column; the array formed by a plurality of the first structural heterogeneous units includes three phase gradients, and the phase of the first structural heterogeneous units is formed by combining the bidirectional phase gradients of the x-axis and y-axis; The array formed by multiple heterogeneous units of the second structure is arranged with the length direction of the spatial propagation region as the y-axis and the width direction as the x-axis, and the x-axis as the row and the y-axis as the column; the array of multiple heterogeneous units of the second structure includes two phase gradients, which correspond to the phase gradient of the outer large cross structure and the phase gradient of the inner small cross structure, respectively; the phase of the heterogeneous unit of the second structure is formed by combining the bidirectional phase gradients of the x-axis and y-axis.

[0008] In some embodiments, the three phase gradients formed by the array of the first structural heterogeneous units include a first metal ring phase gradient, a second metal ring phase gradient, and a third metal ring phase gradient, and the two phase gradients formed by the array of the second structural heterogeneous units include a first double cross phase gradient and a second double cross phase gradient. When the external double-open-ring resonator operates with the phase gradient of the first metal ring, the phase difference of the first structural heterogeneous unit adjacent in the same row of the phase gradient of the first metal ring includes the first phase difference. When the intermediate double-opening ring-slot resonator operates with the second metal ring phase gradient, the phase difference of the first structural heterogeneous unit adjacent to the second metal ring phase gradient includes the second phase difference. When the internal arc resonator operates with the third metal ring phase gradient, the phase difference of the first structural heterogeneous units adjacent in the same row of the third metal ring phase gradient includes the third phase difference. The first double-cross phase gradient is set according to the external cross structure of the second structural heterogeneous unit; The second double cross phase gradient is set according to the internal cross structure of the second structural heterogeneous unit.

[0009] In some embodiments, the first structural heterogeneous unit further includes an isolation ring, which is used to shield interference between resonances of different frequencies; The second structural heterogeneous unit further includes a circular aperture structure, which is used to suppress crosstalk between adjacent second structural heterogeneous units through a shielding effect.

[0010] In some embodiments, when the first structural heterogeneous unit generates and modulates the artificial surface wavefront to be an artificial surface Bessel beam at the frequency of the first metal ring, the phase of the external double-opening ring resonator in the phase gradient of the first metal ring is the phase of the artificial surface Bessel beam. When the first structural heterogeneous unit generates and modulates the artificial surface wave to not perform wavefront shaping at the frequency of the second metal ring, the phase of the intermediate double-opening ring slot resonator in the phase gradient of the second metal ring is the artificial surface wave excitation phase. When the first structural heterogeneous unit generates and modulates the artificial surface beam wavefront to be an artificial surface focused beam at the frequency of the third metal ring, the phase of the internal arc resonator in the phase gradient of the third metal ring is the phase of the artificial surface focused beam.

[0011] In some embodiments, the process of obtaining the phase of the Bessel beam on the artificial surface includes the following steps: The first Bessel product is obtained by multiplying the intrinsic wave vector with the abscissa; the intrinsic wave vector includes the negative vector of the artificial surface wave at the frequency of the first metal ring, and the abscissa includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit. The second Bessel product is obtained by multiplying the intrinsic wave vector, the absolute value of the ordinate, and the numerical aperture; the intrinsic wave vector includes the vector of the artificial surface wave at the frequency of the first metal ring, and the ordinate includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit. The phase of the artificial surface Bessel beam is obtained by adding the first Bessel product and the second Bessel product. The process of obtaining the artificial surface wave excitation phase includes the following steps: The excitation phase of the artificial surface wave is obtained by multiplying the intrinsic wave vector with the abscissa; the intrinsic wave vector includes the negative vector of the artificial surface wave at the frequency of the second metal ring, and the abscissa includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit; The process of obtaining the phase of the artificial surface focusing beam includes the following steps: The first focusing product is obtained by multiplying the intrinsic wave vector with the abscissa; the intrinsic wave vector includes the negative vector of the artificial surface wave at the frequency of the third metal ring; the abscissa includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit. The square of the ordinate is added to the square of the focal distance to obtain the focal sum; the ordinate includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit, and the focal distance includes the distance from the starting point to the focal point of the artificial surface focusing beam; After taking the square root of the sum of the focused points, the difference between the square root sum of the focused points and the distance to the focal point is calculated as the first difference. The first difference is multiplied by the intrinsic wave vector to obtain the second focusing product; the intrinsic wave vector includes the vector of the artificial surface wave at the frequency of the third metal ring; The phase of the artificial surface focused beam is obtained by adding the first focusing product and the second focusing product.

[0012] In some embodiments, when the second structural heterogeneous unit generates and modulates the artificial surface wave far-field radiation wavefront to form a first holographic image at a first double cross frequency, the phase of the outer cross structure in the first double cross phase gradient is the phase of the first holographic image; the first holographic image includes a first display mark and a second display mark. When the second structural heterogeneous unit generates and modulates the space beam wavefront to form a second holographic image at the second double cross frequency, the phase of the inner cross structure in the second double cross phase gradient is the phase of the second holographic image; the second holographic image includes a third display mark and a fourth display mark.

[0013] In some embodiments, the process of the artificial surface wave performing far-field radiation and generating the phase of the first holographic image includes the following steps: The eigenvector and the abscissa are multiplied to obtain the holographic reference product; the eigenvector includes the vector of the artificial surface wave at the first double cross frequency, and the abscissa includes the coordinate value corresponding to the geometric center of the second structural heterogeneous unit; The difference between the holographic reference product and the phase of the first display mark is calculated to obtain the artificial surface wave far-field radiation and generate the phase of the first display mark; The difference between the product of the holographic reference and the phase of the second display mark is calculated to obtain the far-field radiation of the artificial surface wave and generate the phase of the second display mark; The process of wavefront modulation of the spatial beam to generate the phase of the second holographic image includes the following steps: The phase of the third display mark is the same as the phase of the space wave under x-polarized incident. The phase of the fourth display mark is the same as the phase of the space wave under x-polarized incident light.

[0014] In some embodiments, the material of the bottom metal reflective layer includes copper; The material of the intermediate dielectric layer includes polytetrafluoroethylene glass fiber cloth copper foil plate; The material of the top metal composite structure includes copper.

[0015] In some embodiments, independent multi-channel wavefront modulation of the artificial surface wave and the space wave is performed by adjusting the structural dimensions and rotation angles of the first structural heterogeneous unit and the second structural heterogeneous unit.

[0016] The embodiments of this application include at least the following beneficial effects: This application provides a wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces. This scheme effectively achieves total reflection of incident electromagnetic waves by relying on the bottom metal reflective layer, while isolating external electromagnetic interference at the bottom, significantly improving the anti-interference capability and electromagnetic stability of the wavefront modulation device. The intermediate dielectric layer enables both electromagnetic wave phase modulation and stable waveguide transmission. By rationally dividing the intermediate dielectric layer into a surface excitation region, a surface transmission region, and a spatial propagation region, a clearly defined functional layout is achieved. The surface transmission region, without the need for a metal structure, can... To ensure stable and low-loss propagation of artificial surface waves, the first structural heterogeneous unit deployed in the surface excitation region and the second structural heterogeneous unit deployed in the spatial propagation region have clearly defined roles and responsibilities. By flexibly adjusting the rotation angle of the nested metal ring structure within the first structural heterogeneous unit, complete 2π phase coverage can be achieved at multiple different operating frequencies. Relying on the nested double-cross metal structure within the second structural heterogeneous unit, adjusting its major axis, minor axis, and rotation angle can also adapt to different operating frequencies to achieve full-range phase coverage. Combined with the synergistic effect of the top metal composite structure located on the upper surface of the intermediate dielectric layer, precise control of the phase and amplitude of electromagnetic waves can be achieved simultaneously. The wavefront control device overcomes the drawbacks of traditional optical control devices, such as large size, low integration, and single operating mode, effectively improving the overall structural integration and space utilization. It can simultaneously achieve multi-dimensional precise wavefront control of artificial surface waves and space waves, has multi-frequency adaptable control capabilities, rich control dimensions, and is applicable to a wide range of working scenarios. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the intermediate dielectric layer provided in the embodiments of this application; Figure 2 This is a three-dimensional diagram of the first structural heterogeneous unit; Figure 3 This is a top view of the first structural heterogeneous unit; Figure 4 This is a three-dimensional diagram of the second structural heterogeneous unit; Figure 5 This is a top view of the second structural heterogeneous unit; Figure 6 This is a schematic diagram showing the amplitude and phase of an external double-open-ring resonator when rotated at different angles; Figure 7 This is a schematic diagram showing the amplitude and phase of a double-opening annular slot resonator rotated at different angles. Figure 8 This is a schematic diagram showing the amplitude and phase of the internal arc resonator when rotated at different angles; Figure 9 This is a schematic diagram of the dispersion curve of the surface transport unit; Figure 10 This is a schematic diagram of the reflection amplitude and phase of the second structural heterogeneous unit in the spatial propagation region under different arm lengths, when it is homopolarized by the incident orthogonal linearly polarized wave; Figure 11 This is a schematic diagram of the phase distribution and arrangement of the surface excitation regions at different frequencies; Figure 12 This is a schematic diagram of the phase distribution of the spatial propagation region under orthogonal circular polarization channels at 10.5 GHz for artificial surface wave far-field radiation and holographic imaging. Figure 13 This is a schematic diagram of the phase distribution of the spatial propagation region under the incident orthogonal linearly polarized wave at 18.0 GHz for spatial holographic imaging; Figure 14 This is a schematic diagram of the metasurface electric field distribution on a plane with z=20mm under right-hand circularly polarized wave incident at different operating frequencies; Figure 15 This is a schematic diagram of the target image and the simulated image on the z=220mm plane under the orthogonal circular polarization channel at 10.5GHz; Figure 16 This is a schematic diagram of the target image and the simulated image on the z=240mm plane under different polarization states at 18.0GHz. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0020] In some embodiments, a wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces adopts a three-layer stacked structure, mainly composed of a bottom metal reflective layer, an intermediate dielectric layer, and a top metal composite structure arranged sequentially from top to bottom. The three layers work together to achieve precise multidimensional wavefront modulation of artificial surface waves and space waves. The bottom metal reflective layer, as the underlying functional structure of the device, can achieve total reflection of incident electromagnetic waves and effectively isolate external electromagnetic signal interference, avoiding the influence of stray electromagnetic fields on the internal electromagnetic wave modulation process, thus ensuring the stability and modulation accuracy of the device. The top metal composite structure, located on the upper surface of the intermediate dielectric layer, can synchronously modulate the phase and amplitude of electromagnetic waves during transmission, working in conjunction with the intermediate dielectric layer to complete multidimensional, multi-mode electromagnetic beam wavefront modulation functions. During operation, electromagnetic waves are incident on the top metal composite structure. Specifically, spatial waves are directly and perpendicularly incident on the top metal composite structure above the corresponding spatial propagation region 130. Artificial surface waves are coupled and excited by the first heterogeneous unit of the top metal composite structure above the surface excitation region 110, and are bound to the interface of the intermediate dielectric layer and propagated laterally along the dielectric layer. The bottom metal reflective layer is a total reflection copper layer, which reflects the downward transmitted electromagnetic waves back to the intermediate dielectric layer and the top metal composite structure, preventing energy leakage downward.

[0021] The intermediate dielectric layer, fixedly connected above the bottom metal reflective layer, is the core functional layer for electromagnetic wave phase modulation and optical waveguide transmission, playing a crucial role in waveguide transmission, phase modulation, and wavefield manipulation. To achieve zoned and multifunctional electromagnetic wave manipulation, the intermediate dielectric layer is divided into three functionally independent but mutually cooperating regions: the surface excitation region 110 on the left, the surface transmission region 120 in the center, and the spatial propagation region 130 on the right. These three functional regions work together to form the core functional system of the heterogeneous metasurface of the wavefront manipulation device, which can respectively perform differentiated functions such as artificial surface wave excitation and transmission, and spatial wave modulation radiation. The surface transmission region 120 has no metal structure, which can provide a stable transmission channel for artificial surface waves without interference and with low loss, ensuring that artificial surface waves propagate smoothly along the medium interface. The surface excitation region 110 has multiple first-structure heterogeneous units arranged in an array, while the space propagation region 130 has multiple second-structure heterogeneous units arranged in an array. Through the differentiated structural design and parameter control of the two types of heterogeneous units, the multi-dimensional wavefront control of artificial surface waves and space waves can be achieved.

[0022] The first heterogeneous unit, employing a nested metal ring structure, is the core unit for achieving multi-frequency phase modulation of artificial surface waves. The wavefront modulation device can independently adjust the rotation angle of each metal ring within the first heterogeneous unit, leveraging the differences in the resonant characteristics of the different metal rings to achieve complete 2π phase coverage at three different operating frequencies, meeting the wavefront modulation requirements for multi-frequency multiplexed artificial surface wave beams. The second heterogeneous unit uses a nested double-cross metal structure, adapting to the multi-dimensional phase modulation requirements of space waves. By adjusting the major and minor axis dimensions and the overall rotation angle of the two sets of cross metal structures within the second heterogeneous unit, complete 2π phase coverage can be achieved at two different operating frequencies, realizing full-phase modulation across multiple frequency domains of space waves and effectively broadening the operating frequency band and modulation dimensions of the wavefront modulation device.

[0023] For the surface excitation region 110 of the intermediate dielectric layer, the wavefront modulation device establishes an array arrangement reference with the length direction of the region as the y-axis and the width direction as the x-axis, and the x-axis as the column, thus completing the regular array layout of the first structural heterogeneous unit. Based on the array arrangement, the array of the first structural heterogeneous unit in the surface excitation region 110 can form three independent phase gradients, defined as the first metal ring phase gradient, the second metal ring phase gradient, and the third metal ring phase gradient. The three phase gradients correspond one-to-one with the external double-opening ring resonator, the intermediate double-opening ring slot resonator, and the internal arc resonator inside the first structural heterogeneous unit. Moreover, the final phase of each first structural heterogeneous unit is formed by the bidirectional combination of the phase gradient of the first structural heterogeneous unit in the x-axis direction and the phase gradient in the y-axis direction, realizing precise phase modulation in a two-dimensional plane.

[0024] The three metal ring phase gradients possess differentiated phase arrangement parameters, enabling multi-channel independent control capabilities. Specifically, when the external double-opening ring resonator operates with the first metal ring phase gradient, within the array arrangement range, adjacent first structural heterogeneous units in each row of the surface excitation region 110 maintain a first phase difference, preferably a fixed phase difference of 45°. When the intermediate double-opening ring-slot resonator operates with the second metal ring phase gradient, adjacent first structural heterogeneous units in each row of the surface excitation region 110 maintain a second phase difference, preferably a fixed phase difference of 68°. When the internal arc-shaped resonator operates with the third metal ring phase gradient, adjacent first structural heterogeneous units in each row of the surface excitation region 110 maintain a third phase difference, preferably a fixed phase difference of 85°. Through the independent configuration of these three different phase gradients, the phase control requirements of artificial surface waves at three different operating frequencies are matched, achieving multi-frequency, multi-dimensional, and multi-channel wavefront control of artificial surface waves.

[0025] For the spatial propagation region 130 of the intermediate medium layer, the wavefront manipulation device also uses the length direction of the spatial propagation region 130 as the y-axis and the width direction as the x-axis, following the rule of x-axis as rows and y-axis as columns to complete the array arrangement of the second structural heterogeneous units. The array of second structural heterogeneous units, after arrangement, can form two independent phase gradients, defined as the first double-cross phase gradient and the second double-cross phase gradient, respectively. These two phase gradients correspond to the manipulation of the outer large cross structure and the inner small cross structure of the second structural heterogeneous units. Consistent with the phase manipulation principle of the first structural heterogeneous unit, the phase of each second structural heterogeneous unit is also composed of a combination of bidirectional phase gradients along the x-axis and y-axis. Relying on the differentiated phase gradient design of the inner and outer cross structures, multi-dimensional and high-precision wavefront manipulation of space waves is achieved. Combined with the manipulation capability of the first structural heterogeneous unit, synchronous multi-dimensional wavefront manipulation of artificial surface waves and space waves is ultimately completed.

[0026] In some embodiments, the wavefront control device for artificial surface waves and space waves based on heterogeneous metasurfaces adopts a layered composite structure. Each functional layer is equipped with a fixed adaptable material to ensure electromagnetic control performance. The bottom metal reflective layer is made of copper, which can effectively achieve total reflection of incident electromagnetic waves and completely isolate bottom electromagnetic interference, avoiding the impact of the bottom environment on the control accuracy of the device. The middle dielectric layer is made of polytetrafluoroethylene glass fiber cloth copper foil (F4B). F4B has excellent electromagnetic wave transmission performance and phase control performance, which can stably support the upper metal structure and complete the waveguide transmission and phase preprocessing of electromagnetic waves. The top metal composite structure is also made of copper. Relying on the good electromagnetic response characteristics of copper, precise control of the phase and amplitude of electromagnetic waves can be achieved, ensuring the control stability and working efficiency of the overall device.

[0027] The intermediate dielectric layer is divided into three functional regions: a surface excitation region 110, a surface transmission region 120, and a spatial propagation region 130. The surface excitation region 110 is arrayed with multiple first-structure heterogeneous units. These units employ a nested metal ring structure and integrate an isolation ring structure. The isolation ring effectively avoids crosstalk between resonant signals of different frequencies, ensuring the independence and accuracy of multi-frequency modulation. By independently adjusting the rotation angles of the nested external double-opening ring resonator, the intermediate double-opening ring slot resonator, and the internal arc-shaped resonator within the first-structure heterogeneous unit, complete 2π phase coverage can be achieved at three different operating frequencies: the first metal ring frequency, the second metal ring frequency, and the third metal ring frequency, achieving a multi-frequency multiplexing modulation effect. The preferred first metal ring frequency is 7.0 GHz, the preferred second metal ring frequency is 10.5 GHz, and the preferred third metal ring frequency is 13.0 GHz. Different frequencies correspond to different artificial surface beam wavefront modulation patterns and phase rules.

[0028] Specifically, at a working frequency of 7.0 GHz, the first structural heterogeneous unit can achieve wavefront modulation of the artificial surface Bessel beam. At this time, the modulation phase of the external double-opening ring resonator in the phase gradient of the first metal ring is the phase of the artificial surface Bessel beam. The phase of the artificial surface Bessel beam is calculated using a specific algorithm: First, the eigenvector of the artificial surface wave at 7.0 GHz is negatively evaluated and multiplied by the abscissa corresponding to the geometric center of the first structural heterogeneous unit to obtain the first Bessel product; then, the eigenvector of the artificial surface wave at 7.0 GHz, the absolute value of the ordinate corresponding to the geometric center of the first structural heterogeneous unit, and the preset numerical aperture are multiplied to obtain the second Bessel product; finally, the first Bessel product and the second Bessel product are added together to obtain the accurate phase of the artificial surface Bessel beam. The formula for calculating the phase of the artificial surface Bessel beam is: ; in, Indicates the phase of the Bessel beam on the artificial surface. The eigenvectors of the artificial surface wave at 7.0 GHz are represented by x and y, which represent the abscissa and ordinate of the geometric center within the surface excitation region 110, respectively. Indicates numerical aperture.

[0029] At a working frequency of 10.5 GHz, the wavefront modulation device does not require wavefront shaping of the artificial surface wave (SSW). It only needs to achieve stable SSW excitation transmission. At this point, the modulation phase of the double-opening ring-slot resonator in the middle of the second metal ring phase gradient is the SSW excitation phase. The intrinsic wave vector of the SSW at 10.5 GHz is directly negative, and multiplied by the abscissa corresponding to the geometric center of the first structural heterogeneous unit. The result is the SSW excitation phase, ensuring distortion-free and stable transmission of the SSW in the transmission region. The formula for calculating the SSW excitation phase is: ; in, Indicates the phase of artificial surface wave excitation. This represents the eigenvector of artificial surface waves at 10.5 GHz. This represents the x-coordinate corresponding to the geometric center of the first structural heterogeneous unit.

[0030] At a working frequency of 13.0 GHz, the first structural heterogeneous unit can achieve wavefront modulation of the artificial surface focused beam. At this time, the modulation phase of the internal arc resonator in the phase gradient of the third metal ring is the phase of the artificial surface focused beam. The phase acquisition steps are as follows: Take the negative value of the intrinsic wave vector of the artificial surface wave at 13.0 GHz and multiply it by the abscissa corresponding to the geometric center of the first structural heterogeneous unit to obtain the first focusing product; add the square of the ordinate of the geometric center of the unit to the square of the distance from the starting point of the artificial surface focused beam to the focal point to obtain the focusing sum; after taking the square root of the focusing sum, calculate the difference between the square root result and the focusing distance to obtain the first difference value; multiply the first difference value by the intrinsic wave vector of the artificial surface wave at 13.0 GHz to obtain the second focusing product; finally, add the first focusing product and the second focusing product to obtain the phase of the artificial surface focused beam, achieving precise focusing modulation of the artificial surface wave. The formula for calculating the phase of the artificial surface focused beam is: ; in, Indicates the phase of the focused beam on the artificial surface. This represents the eigenvector of artificial surface waves at 13.0 GHz. This represents the x-coordinate corresponding to the geometric center of the first structural heterogeneous unit. The ordinate represents the ordinate corresponding to the geometric center of the first structural heterogeneous unit, and F represents the distance from the starting point to the focal point of the artificial surface focusing beam.

[0031] The spatial propagation region 130 of the intermediate dielectric layer is arrayed with multiple second-structure heterogeneous units. These second-structure heterogeneous units are nested double-cross metal structures and feature circular aperture structures. These circular aperture structures effectively suppress electromagnetic crosstalk between adjacent second-structure heterogeneous units through electromagnetic shielding, improving the overall control consistency of the array. By adjusting the major and minor axis dimensions and rotation angles of the external large cross structure and the internal small cross structure within the second-structure heterogeneous units, complete 2π phase coverage can be achieved under different operating frequencies and polarization incident conditions. This allows for both circular and linear polarization multiplexing capabilities, enabling simultaneous multi-channel control of artificial surface wave far-field holographic imaging and space wave holographic imaging.

[0032] Using the length direction of the spatial propagation region 130 as the y-axis and the width direction as the x-axis, the second structural heterogeneous unit array is arranged with the x-axis as the row and the y-axis as the column. This array forms two independent phase gradients, corresponding to two nested cross structures. The outer large cross structure corresponds to the first double-cross phase gradient and is mainly used for holographic wavefront modulation of artificial surface wave far-field radiation at the first double-cross frequency. This enables the imaging of a first holographic image including a first and second display mark. The first double-cross frequency is preferably 10.5 GHz; for example, the first display mark is "L" and the second display mark is "R". The inner small cross structure corresponds to the second double-cross phase gradient and is mainly used for spatial beam wavefront modulation at the second double-cross frequency. This enables the imaging of a second holographic image including a third and fourth display mark. The second double-cross frequency is preferably 18.0 GHz; for example, the third display mark is "HU" and the fourth display mark is "ST". The two phase gradients are independent and do not interfere with each other, achieving multi-channel holographic modulation with dual frequency bands and dual waveforms.

[0033] For the phase of the first holographic image of the artificial surface wave far-field radiation at 10.5 GHz, a partitioned independent phase calculation method is adopted: First, the eigenvector of the artificial surface wave at 10.5 GHz is multiplied by the abscissa of the geometric center of the second structural heterogeneous unit to obtain the holographic reference product; the intrinsic phase of the first display mark "L" is subtracted from the holographic reference product to obtain the control phase of the artificial surface wave far-field radiation generating the "L" image; the intrinsic phase of the second display mark "R" is subtracted from the holographic reference product to obtain the control phase of the artificial surface wave far-field radiation generating the "R" image. The two sets of phases are independently controlled, enabling far-field holographic imaging of the two marked images respectively. The phase of the artificial surface wave far-field radiation generating the holographic images "L" and "R" is represented as follows: ; in, This indicates the phase of artificial surface wave far-field radiation that produces the first display mark "L". This indicates the phase of artificial surface wave far-field radiation, which produces the second display mark "R". This represents the eigenvector of artificial surface waves at 10.5 GHz. This represents the x-coordinate corresponding to the geometric center of the second structural heterogeneous unit. Indicates the phase marked "L" in the first display. This indicates the phase of the second display marker "R".

[0034] For the phase of the second holographic image of a space wave at 18.0 GHz, an independent control rule based on polarization matching is adopted: under x-polarized incident conditions, the unit phase matches the inherent phase of the third display marker "HU", enabling the imaging of the "HU" holographic image; under y-polarized incident conditions, the unit phase matches the inherent phase of the fourth display marker "ST", enabling the imaging of the "ST" holographic image. Relying on the linear polarization multiplexing characteristic, independent imaging control of dual images under different polarization incident conditions for the same structural unit is achieved. The phase of the space wavefront modulated and generating the third display marker "HU" and the fourth display marker "ST" is represented as follows: ; in, This indicates the phase of a space wave under x-polarized incident light, marked with the third indicator "HU". This indicates the phase marked "ST" produced by the space wave under y-polarized incident radiation. This indicates the phase marked "HU" in the third display. This indicates the fourth phase marked "ST".

[0035] Based on the phase formulas for artificial surface Bessel beams, artificial surface wave excitation, or artificial surface focusing beams, the phases of the artificial surface Bessel beam, artificial surface wave, or artificial surface focusing beam are obtained. By changing the rotation angle of the nested open-ring structure, corresponding to different first structural heterogeneous units, the first structural heterogeneous units on the surface excitation region 110 are arranged according to their corresponding phases. When a right-hand circularly polarized wave is incident at 7.0 GHz, an artificial surface Bessel beam wavefront is generated in the surface transmission region 120; when a right-hand circularly polarized wave is incident at 10.5 GHz, an artificial surface beam is generated in the surface transmission region 120; and when a right-hand circularly polarized wave is incident at 13.0 GHz, an artificial surface focusing beam wavefront is generated in the surface transmission region 120, thus achieving independent multi-channel wavefront modulation of the artificial surface wave.

[0036] Based on the phase formula for artificial surface wave far-field radiation and holographic imaging, the phases of the holographic images "L" and "R" generated by the artificial surface wave far-field radiation wavefront at 10.5 GHz are obtained. According to this phase, by changing the size and rotation angle of the external large cross structure of the second structural heterogeneous unit, corresponding to different units, the second structural heterogeneous units on the spatial propagation region 130 are arranged according to the corresponding phases. At 10.5 GHz, the artificial surface wave generated by the surface transmission region 120 is incident on the spatial propagation region 130, generating the holographic image "L" in the left-hand circular polarization channel and the holographic image "R" in the right-hand circular polarization channel, thus realizing artificial surface wave far-field radiation and holographic imaging.

[0037] Based on the phase formula for space wave wavefront modulation and holographic imaging, the phases of the holographic images "HU" and "ST" generated by space waves at 18.0 GHz are obtained. According to these phases, by changing the dimensions of the small cross structures within the second structural heterogeneous unit along the major and minor axes, corresponding to different units, the units on the spatial propagation region 130 are arranged according to the corresponding phases. At 18.0 GHz, the holographic image "HU" is generated under x-polarized wave incidence, and the holographic image "ST" is generated under y-polarized wave incidence, thus achieving space wave holographic imaging. Compared with previous metasurface wavefront modulation devices, this application has subwavelength-level modulation capability, high integration, and multifunctionality, greatly changing the flexibility of electromagnetic wave modulation. This technology has enormous potential in far-field radiation and near-field modulation applications of electromagnetic waves.

[0038] In some embodiments, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, Figure 2 and Figure 3 All Figure 1 A schematic diagram of the first structural heterogeneous units arranged in an array in the mid-surface excitation region 110. Figure 4 and Figure 5 All Figure 1 A schematic diagram of the second structural heterogeneous units arranged in an array in the mid-space propagation region 130. Preferably, Figure 2 The first structural heterogeneous unit shown in the figure has a uniform period length p of p=10mm, a dielectric layer thickness h=2mm, and a bottom metal reflective layer and a top metal composite structure layer thickness of 0.035mm. The above overall structural parameters are determined by simulation optimization using the finite-time difference method to ensure the efficient transmission and control performance of electromagnetic waves in each layer of the structure.

[0039] Figure 2 and Figure 3 The first structural heterogeneous unit is located in the surface excitation region 110. It is a nested multilayer metal ring resonant structure, consisting of an outer double-opening ring resonator, a middle double-opening ring slot resonator, an electrostatic shielding ring (isolation ring), and an inner arc-shaped resonator, from the outside in. Specific structural parameters are: the outer radius of the outer double-opening ring resonator... =4.7mm, opening angle =30°; Outer ring radius of the middle double-opening ring-slot resonator =4.1mm, outer radius of inner ring =3.5mm; Outer radius of the electrostatic shielding ring =2.9mm; outer radius of the internal arc resonator =2.3mm, opening angle =60°; the linewidth of all ring resonators is uniformly set to 60°. =0.3mm. By jointly optimizing the above-mentioned radius, angle and linewidth parameters using the finite-time difference method, the first structural heterogeneous unit can realize wavefront modulation of artificial surface Bessel beam, artificial surface wave excitation transmission and artificial surface focusing beam at three different frequencies of 7.0GHz, 10.5GHz and 13.0GHz, respectively. At the same time, the electrostatic shielding ring can effectively suppress electromagnetic crosstalk between different frequency resonant modes and ensure the independence of multi-frequency modulation.

[0040] Figure 4 and Figure 5 The second structural heterogeneous unit is located in the spatial propagation region 130. This second structural heterogeneous unit is a nested double-cross metal structure, comprising a circular aperture shielding structure, an outer large cross structure, and an inner small cross structure. Specific structural parameters are: circular aperture radius... =4.7mm, outer radius of the external large cross structure =2.8mm, inner radius =2.6mm, arm width of the external large cross structure =0.8mm, arm width of the internal small cross structure =0.5mm. The inner and outer radii, arm width and circular aperture size of the cross structure are optimized by the finite-time difference method. The second structural heterogeneous unit can realize artificial surface wave far-field holographic radiation and spatial wave line polarization holographic imaging at frequencies of 10.5GHz and 18.0GHz, respectively. The circular aperture structure effectively suppresses crosstalk between adjacent second structural heterogeneous units through electromagnetic shielding effect, ensuring the control accuracy of array phase gradient.

[0041] After structural parameter optimization, the wavefront modulation device can achieve stable electromagnetic wave response at various operating frequencies. The first structural heterogeneous unit can independently control the wavefront morphology of artificial surface waves at different frequencies, and the second structural heterogeneous unit can realize far-field radiation and imaging of dual holographic images under different polarization and frequency conditions. The wavefront modulation device realizes multi-frequency, multi-channel and independent wavefront modulation of artificial surface waves and space waves.

[0042] In some embodiments, a preset phase arrangement sequence is calculated using a phase formula, and structural parameters on each first and second structural heterogeneous unit are set according to the preset phase arrangement sequence, thereby achieving independent multi-channel wavefront modulation of artificial surface waves and space waves. The specific process is as follows: Step 1: Electromagnetic properties of the first and second structural heterogeneous units and the dispersion relation of the artificial surface waves supported by the surface transmission region 120. Specifically, for the first structural heterogeneous unit, such as... Figure 6 , Figure 7 and Figure 8 As shown, the rotation angles of the external double-opening ring resonator, the intermediate double-opening ring slot resonator, and the internal arc-shaped resonator are independently adjusted (e.g., Figure 3 In , , Under right-hand circularly polarized wave incidence, the device achieves complete 2π phase coverage of the cross-polarization components at frequencies of 7.0 GHz, 10.5 GHz, and 13.0 GHz, with reflection amplitudes exceeding 0.8 in each case. Therefore, the first structural heterogeneous unit can operate at three different frequencies, achieving frequency reuse. Figure 9 The dispersion relation of artificial surface waves was demonstrated, where all three eigenvectors—the eigenvectors of artificial surface waves at 7.0 GHz, 10.5 GHz, and 13.0 GHz—are located below the light source, thus ensuring their non-radiative properties. Furthermore, for the second structural heterogeneous unit, such as... Figure 10 Parts a, b, e, and f are shown in the diagram. Part a represents changing the amplitude of the large cross structure arm width at 10.5 GHz under x-polarized wave incidence; part b represents changing the phase of the large cross structure arm width at 10.5 GHz under x-polarized wave incidence; part e represents changing the amplitude of the small cross structure arm width at 18.0 GHz under x-polarized wave incidence; and part f represents changing the phase of the small cross structure arm width at 18.0 GHz under x-polarized wave incidence. By independently adjusting the arm length u of the outer large cross structure and the arm length x of the inner small cross structure, complete 2π phase coverage of the common polarization component is achieved at frequencies of 10.5 GHz and 18.0 GHz under x-polarized wave incidence, with a reflection amplitude exceeding 0.95. Due to the structural symmetry of the second structural heterogeneous unit, as... Figure 10 As shown in parts c, d, g, and h, part c represents changing the amplitude of the large cross structure arm width at 10.5 GHz under y-polarized wave incidence; part d represents changing the phase of the large cross structure arm width at 10.5 GHz under y-polarized wave incidence; part g represents changing the amplitude of the small cross structure arm width at 18.0 GHz under y-polarized wave incidence; and part h represents changing the phase of the small cross structure arm width at 18.0 GHz under y-polarized wave incidence. The same characteristics can be obtained for y-polarized wave incidence at both 10.5 GHz and 18.0 GHz frequencies. Therefore, the second structural heterogeneous unit can operate at two different frequencies and two polarization states, achieving polarization-frequency multiplexing.

[0043] Step 2: As Figure 11 As shown in section a, section a represents the phase distribution of the artificial surface Bessel beam at 7.0 GHz, where different colors indicate different phases. The phase of the artificial surface Bessel beam is calculated using the artificial surface Bessel beam phase formula, as shown below. Figure 11 As shown in section b, section b represents the phase distribution of the artificial surface wave at 10.5 GHz, where different colors indicate different phases. The phase of the artificial surface wave is calculated using the artificial surface wave phase formula, as shown below. Figure 11 As shown in section c, section c represents the phase distribution of the artificial surface focused beam at 13.0 GHz, where different colors indicate different phases. The phase of the artificial surface focused beam with a focal length of 220 mm is calculated using the artificial surface focused beam phase formula. The calculation is based on the artificial surface wave far-field radiation and holographic imaging phase formulas, as follows... Figure 12 As shown in part a, part a represents the phase distribution under the left-hand circularly polarized channel, where different colors indicate different phases. The phase of the holographic image "L" generated by the far-field radiation wavefront of the artificial surface wave at the z=220mm plane is obtained. The phase is calculated according to the formula for the far-field radiation and holographic imaging of the artificial surface wave, as follows: Figure 12 As shown in part b, part b represents the phase distribution under the right-hand circularly polarized channel, where different colors indicate different phases. The phase of the holographic image "R" generated by the far-field radiation wavefront of the artificial surface wave at the z=220mm plane is obtained. The calculation is based on the spatial wavefront modulation and holographic imaging phase formula, as follows... Figure 13 As shown in part a, part a represents the phase distribution under the incident x-polarized wave, where different colors indicate different phases. The phase of the holographic image "HU" generated by the space wave at the z=240mm plane is obtained. The calculation is based on the space wavefront modulation and holographic imaging phase formula, as follows: Figure 13 As shown in part b, part b represents the phase distribution under the incident y-polarized wave, where different colors indicate different phases, and the phase of the holographic image "ST" generated by the space wave at the z=240mm plane is obtained.

[0044] Step 3: Based on the phase distribution results calculated in Step 2, by changing the structural dimensions and rotation angles of the first and second structural heterogeneous units, the corresponding units are selected to construct the structural heterogeneous surface, thereby realizing independent multi-channel wavefront modulation of artificial surface waves and space waves.

[0045] Based on numerical simulations, the results of multidimensional wavefront manipulation of structurally heterogeneous metasurfaces using artificial surface waves and space waves were obtained, such as... Figure 14 As shown, Figure 14 Part a represents the electric field distribution of the artificial surface Bessel beam at 7.0 GHz, and part a is the electric field distribution of the artificial surface Bessel beam on the z=20 mm plane; Figure 14 Part b represents the electric field distribution of the artificial surface wave at 10.5 GHz, and part b is the electric field distribution of the artificial surface wave on the z=20 mm plane; Figure 14Part c represents the electric field distribution of the artificial surface focused beam at 13.0 GHz. Part c is the electric field distribution of the artificial surface focused beam with F=220 mm in the z=20 mm plane. Figure 15 As shown, Figure 15 Part a represents the target image and simulated image under the left-hand circular polarization channel. Part a is the target image and electric field distribution map of the artificial surface wave far-field radiation and holographic image "L" in the z=220mm plane within the left-hand circular polarization channel. Figure 15 Part b represents the target image and simulated image under the right-hand circularly polarized channel. Part b is the target image and electric field distribution map of the artificial surface wave far-field radiation and holographic image "R" in the z=220mm plane within the right-hand circularly polarized channel. Figure 15 Part c represents the target image and simulated image under the linearly polarized channel. Part c is the target image and electric field distribution map of the artificial surface wave far-field radiation and holographic image in the z=220mm plane within the linearly polarized channel. For example... Figure 16 As shown, Figure 16 Part a represents the target image and simulated image under the incident x-polarized wave. Part a is the target image and electric field distribution diagram on the z=240mm plane under the incident x-polarized space wave. Figure 16 Part b represents the target image and simulated image under y-polarized wave incident, while part b is the target image and electric field distribution diagram on the z=240mm plane under x-polarized space wave incident. Figure 16 Part c represents the target image and simulated image under 45° linearly polarized wave incident, and part c is the target image and electric field distribution map on the z=240mm plane under 45° linearly polarized space wave incident.

[0046] The wavefront manipulation device for artificial surface waves and space waves based on heterogeneous metasurfaces in this application achieves multi-dimensional independent control of electromagnetic wave amplitude, phase, and polarization, possessing significant advantages such as high integration, multi-band multiplexing, and multi-functional parallelism. It not only overcomes the limitations of traditional optical devices in terms of large size and single control mode, but also simultaneously completes Bessel beam transmission, stable excitation, focusing and shaping, and far-field double holographic radiation of artificial surface waves, while realizing dual-polarization holographic imaging of space waves. This greatly improves the flexibility and integration of electromagnetic wave manipulation, showing broad application prospects in applications such as near-field manipulation and far-field radiation of electromagnetic waves.

[0047] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0048] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0049] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0050] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0051] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0053] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0054] The units described above 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 this embodiment according to actual needs.

[0055] Furthermore, the functional units in the various embodiments of this application 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.

[0056] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces, characterized in that, include: A bottom metal reflective layer is provided to totally reflect incident electromagnetic waves and isolate bottom electromagnetic interference. An intermediate dielectric layer is fixedly connected to the bottom metal reflective layer and is used for phase modulation. The intermediate dielectric layer includes a surface excitation region, a surface transmission region, and a spatial propagation region. Multiple first structural heterogeneous units are arrayed within the surface excitation region, a non-metallic structure is provided within the surface transmission region, and multiple second structural heterogeneous units are arrayed within the spatial propagation region. The first structural heterogeneous units include nested metal ring structures. By adjusting the rotation angle of each metal ring within the nested metal ring structure, complete 2π phase coverage of the artificial surface wave can be achieved at different operating frequencies. The second structural heterogeneous units include nested double-cross metal structures. By adjusting the major axis, minor axis, and rotation angle of the two sets of cross metal structures within the nested double-cross metal structure, complete 2π phase coverage of the artificial surface wave and the spatial wave can be achieved at different operating frequencies. A top metal composite structure is disposed on the upper surface of the intermediate dielectric layer, and the top metal composite structure is used to regulate the phase and amplitude of the artificial surface wave and the space wave.

2. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 1, characterized in that, The array formed by multiple first structural heterogeneous units is arranged with the length direction of the surface excitation region as the y-axis and the width direction as the x-axis, with the x-axis as the row and the y-axis as the column; the array formed by multiple first structural heterogeneous units includes three phase gradients, and the phase of the first structural heterogeneous units is formed by combining the bidirectional phase gradients of the x-axis and y-axis; The array formed by multiple heterogeneous units of the second structure is arranged with the length direction of the spatial propagation region as the y-axis and the width direction as the x-axis, and the x-axis as the row and the y-axis as the column; the array of multiple heterogeneous units of the second structure includes two phase gradients, which correspond to the phase gradient of the outer large cross structure and the phase gradient of the inner small cross structure, respectively; the phase of the heterogeneous unit of the second structure is formed by combining the bidirectional phase gradients of the x-axis and y-axis.

3. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 2, characterized in that, The three phase gradients formed by the array of the first structural heterogeneous units include a first metal ring phase gradient, a second metal ring phase gradient, and a third metal ring phase gradient; the two phase gradients formed by the array of the second structural heterogeneous units include a first double cross phase gradient and a second double cross phase gradient. When the external double-open-ring resonator operates with the phase gradient of the first metal ring, the phase difference of the first structural heterogeneous unit adjacent in the same row of the phase gradient of the first metal ring includes the first phase difference. When the intermediate double-opening ring-slot resonator operates with the second metal ring phase gradient, the phase difference of the first structural heterogeneous unit adjacent to the second metal ring phase gradient includes the second phase difference. When the internal arc resonator operates with the third metal ring phase gradient, the phase difference of the first structural heterogeneous units adjacent in the same row of the third metal ring phase gradient includes the third phase difference. The first double-cross phase gradient is set according to the external cross structure of the second structural heterogeneous unit; The second double cross phase gradient is set according to the internal cross structure of the second structural heterogeneous unit.

4. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 3, characterized in that, The first structural heterogeneous unit also includes an isolation ring, which is used to shield interference between resonances of different frequencies; The second structural heterogeneous unit further includes a circular aperture structure, which is used to suppress crosstalk between adjacent second structural heterogeneous units through a shielding effect.

5. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 3, characterized in that, When the first structural heterogeneous unit generates and modulates the artificial surface wavefront to be an artificial surface Bessel beam at the frequency of the first metal ring, the phase of the external double-opening ring resonator in the phase gradient of the first metal ring is the phase of the artificial surface Bessel beam. When the first structural heterogeneous unit generates and modulates the artificial surface wave to not perform wavefront shaping at the frequency of the second metal ring, the phase of the intermediate double-opening ring slot resonator in the phase gradient of the second metal ring is the artificial surface wave excitation phase. When the first structural heterogeneous unit generates and modulates the artificial surface beam wavefront to be an artificial surface focused beam at the frequency of the third metal ring, the phase of the internal arc resonator in the phase gradient of the third metal ring is the phase of the artificial surface focused beam.

6. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 5, characterized in that, The process of obtaining the phase of the Bessel beam on the artificial surface includes the following steps: The first Bessel product is obtained by multiplying the intrinsic wave vector with the abscissa; the intrinsic wave vector includes the negative vector of the artificial surface wave at the frequency of the first metal ring, and the abscissa includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit. The second Bessel product is obtained by multiplying the intrinsic wave vector, the absolute value of the ordinate, and the numerical aperture; the intrinsic wave vector includes the vector of the artificial surface wave at the frequency of the first metal ring, and the ordinate includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit. The phase of the artificial surface Bessel beam is obtained by adding the first Bessel product and the second Bessel product. The process of obtaining the artificial surface wave excitation phase includes the following steps: The excitation phase of the artificial surface wave is obtained by multiplying the intrinsic wave vector with the abscissa; the intrinsic wave vector includes the negative vector of the artificial surface wave at the frequency of the second metal ring, and the abscissa includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit; The process of obtaining the phase of the artificial surface focusing beam includes the following steps: The first focusing product is obtained by multiplying the intrinsic wave vector with the abscissa; the intrinsic wave vector includes the negative vector of the artificial surface wave at the frequency of the third metal ring; the abscissa includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit. The square of the ordinate is added to the square of the focal distance to obtain the focal sum; the ordinate includes the coordinate value corresponding to the geometric center of the first structural heterogeneous unit, and the focal distance includes the distance from the starting point to the focal point of the artificial surface focusing beam; After taking the square root of the sum of the focused points, the difference between the square root sum of the focused points and the distance to the focal point is calculated as the first difference. The first difference is multiplied by the intrinsic wave vector to obtain the second focusing product; the intrinsic wave vector includes the vector of the artificial surface wave at the frequency of the third metal ring; The phase of the artificial surface focused beam is obtained by adding the first focusing product and the second focusing product.

7. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 3, characterized in that, When the second structural heterogeneous unit generates and modulates the artificial surface wave far-field radiation wavefront to form a first holographic image at the first double cross frequency, the phase of the outer cross structure in the first double cross phase gradient is the phase of the first holographic image; the first holographic image includes a first display mark and a second display mark; When the second structural heterogeneous unit generates and modulates the space beam wavefront to form a second holographic image at the second double cross frequency, the phase of the inner cross structure in the second double cross phase gradient is the phase of the second holographic image; the second holographic image includes a third display mark and a fourth display mark.

8. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 7, characterized in that, The process by which the artificial surface wave performs far-field radiation and generates the phase of the first holographic image includes the following steps: The eigenvector and the abscissa are multiplied to obtain the holographic reference product; the eigenvector includes the vector of the artificial surface wave at the first double cross frequency, and the abscissa includes the coordinate value corresponding to the geometric center of the second structural heterogeneous unit; The difference between the holographic reference product and the phase of the first display mark is calculated to obtain the artificial surface wave far-field radiation and generate the phase of the first display mark; The difference between the product of the holographic reference and the phase of the second display mark is calculated to obtain the far-field radiation of the artificial surface wave and generate the phase of the second display mark; The process of wavefront modulation of the spatial beam to generate the phase of the second holographic image includes the following steps: The phase of the third display mark is the same as the phase of the space wave under x-polarized incident. The phase of the fourth display mark is the same as the phase of the space wave under x-polarized incident light.

9. The wavefront modulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 1, characterized in that, The material of the bottom metal reflective layer includes copper; The material of the intermediate dielectric layer includes polytetrafluoroethylene glass fiber cloth copper foil plate; The material of the top metal composite structure includes copper.

10. The wavefront manipulation device for artificial surface waves and space waves based on heterogeneous metasurfaces according to claim 1, characterized in that, Independent multi-channel wavefront modulation of the artificial surface wave and the space wave is achieved by adjusting the structural dimensions and rotation angles of the first and second structural heterogeneous units.

Images