A design method for realizing non-crosstalk multiplexing super surface

Abstract

The application provides a design method of a non-crosstalk multiplexing super surface based on a local effect and a non-local effect, and contains the following steps: step one, designing a unit structure of the super surface, and screening a unit structure parameter group A with a cross-polar reflectivity higher than 50%; step two, screening a unit structure parameter group B from the unit structure parameter group A, so that the first-order diffraction efficiency of the super surface is higher than 50% when linearly polarized light is obliquely incident; step three, rotating the unit structure, and screening an optimal unit structure parameter from the unit structure parameter group B; step four, designing a wavefront control super surface and obtaining a corresponding phase distribution, so as to determine the unit structure arrangement of the super surface; and step five, the incident light is incident to the super surface at different incident angles, polarizations and wavelengths, and the wavefront control function and the beam deflection function are obtained. The design method is simple and flexible, the super surface designed by using the method is mature in process and easy to integrate, and has a wide application scenario.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-nano optics, and in particular to a design method for realizing a non-crosstalk multiplexing metasurface. BACKGROUND

[0002] A metasurface is an artificial composite material composed of subwavelength unit structures with periodicity or quasi-periodicity. Through the interaction between adjacent subwavelength unit structures (i.e. local effect), the metasurface can perform specific wavefront manipulation on the 0th order diffracted light (i.e. reflected light), and has important application prospects in superlenses, holographic imaging, polarization conversion, etc. Early metasurfaces focused on the manipulation of a single property of incident light. With the deepening of research, multiplexing metasurfaces that can realize the manipulation of multiple properties of incident light are more practical, i.e. integrating multiple functions in the same device. Multiplexing metasurfaces can improve the optical functions and information carried by metasurfaces, and have important application prospects in information encryption, optical anti-counterfeiting, etc.

[0003] At present, multiplexing metasurfaces have the following design methods. Different unit structures at different positions in the metasurface can realize independent electromagnetic wave manipulation. Through the design strategies of "plane cross synthesis", "plane partition superposition" and "spatial multi-layer superposition", multiple functions can be integrated into the same metasurface. However, as the number of integrated optical functions of the metasurface increases, the crosstalk problem between functions and the integration difficulty will also increase. In addition, complex amplitude metasurfaces can simultaneously manipulate the amplitude and phase of electromagnetic waves, which is also a way to realize multiplexing metasurfaces. However, the phase and amplitude properties of electromagnetic waves have inherent correlation, which inevitably affects the phase manipulation and amplitude manipulation of the metasurface. Therefore, the crosstalk problem between functions of the multiplexing metasurface greatly affects the device performance of the metasurface. In addition, as a new type of subwavelength metasurface structure, the metasurface grating can suppress most of the diffraction orders through the local surface plasmon of the unit structure and the grating diffraction effect of all unit structures (i.e. non-local effect), so that the outgoing energy is concentrated in a certain diffraction order, i.e. realizing large-angle and high-efficiency beam deflection. Therefore, the design of optical functions based on different diffraction orders is a new design idea for multiplexing metasurfaces. SUMMARY

[0004] In view of the technical problem of easy crosstalk between functions of the existing multiplexing metasurface, the present application provides a design method for realizing a non-crosstalk multiplexing metasurface. The design method is simple and flexible, mature and effective in technology, and the metasurface designed by the method is mature in process and easy to integrate.

[0005] In order to achieve the above object, the technical scheme of the present application is realized as follows: a design method for realizing non-crosstalk multiplexing super surface, characterized by comprising the following steps:

[0006] Step one: design the unit structure of the super surface, optimize and adjust the size of the unit structure, screen out the unit structure parameters that make the cross-polarization reflectivity of the super surface higher than 50% when the circularly polarized light is vertically incident, and form a unit structure parameter group A;

[0007] Step two: screen the unit structure parameter group A obtained in step one, screen out the unit structure parameters that make the -1 order diffraction efficiency of the super surface higher than 50% when the linearly polarized light is obliquely incident, and form a unit structure parameter group B from the unit structure parameter group A;

[0008] Step three: rotate the unit structure, screen the unit structure parameter group B again, screen out the unit structure parameters that make the -1 order diffraction efficiency of the super surface still higher than 50% when the linearly polarized incident light is obliquely incident at different rotation angles, and determine the unit structure parameters with the highest -1 order diffraction efficiency as the optimal unit structure parameters;

[0009] Step four: based on the unit structure with the optimal parameters, design a wavefront manipulation super surface, obtain the corresponding phase arrangement, and determine the unit structure arrangement of the super surface from the phase gradient arrangement;

[0010] Step five: make the incident light incident to the super surface at different incident angles, polarizations and wavelengths, and obtain the wavefront manipulation function and the beam deflection function; when the circularly polarized light is vertically incident, the super surface has the wavefront manipulation function; when the linearly polarized light is obliquely incident, the grating diffraction effect of the overall unit structure and the local effect of the unit structure jointly act to suppress the diffraction orders other than the -1 diffraction order, so as to realize the super grating mainly with the -1 diffraction order, that is, realize the beam deflection function.

[0011] The unit structure of the super surface is a nano-rod structure with anisotropy, and the super surface unit structure comprises a metal nano-rod, a dielectric layer and a metal layer arranged in sequence from top to bottom, and the metal nano-rod is a cuboid.

[0012] The metal nano-rod and the metal layer are made of gold, silver, copper, aluminum, chromium or a combination of any two or more materials, and the dielectric layer is made of titanium oxide, silicon oxide, zinc oxide, aluminum oxide or a combination of any two or more materials.

[0013] The method for optimizing and adjusting the size of the unit structure in step one is as follows: vertically incident circularly polarized light to the super surface, adjust the length and width parameters of the metal nano-rod, obtain the cross-polarization reflectivity under different length and width parameters of the metal nano-rod, determine the length and width parameter group with the cross-polarization reflectivity higher than 50%, and determine the corresponding unit structure parameter group A.

[0014] The method for screening the unit structure parameters of the metasurface in step two is as follows: linearly polarized light is obliquely incident on the metasurface, the length and width parameters of the metal nanorod determined in step one are adjusted, the diffraction efficiency of each order of the metal nanorod under different length and width parameters is obtained, the length and width parameter group of the nanorod with the-1 order diffraction efficiency higher than 50% is screened, and the corresponding unit structure parameter group B is determined.

[0015] The method for screening the unit structure parameter group B again in step three is as follows: the unit structure is rotated at different angles, linearly polarized light is obliquely incident on the metasurface, the length and width parameter group of the metal nanorod screened in step two is adjusted, the-1 order diffraction efficiency of the metal nanorod under different rotation angles is obtained, the length and width parameter group of the metal nanorod with the-1 order diffraction efficiency higher than 50% at each rotation angle is screened, and finally an optimal length and width parameter of the metal nanorod is determined.

[0016] The method for designing the metasurface with a specific wavefront manipulation function in step four is as follows: a wavefront manipulation function is designed, and a corresponding phase gradient distribution is obtained; the phase is realized based on a geometric phase, the geometric phase is carried by cross-polarized circular polarization components and is twice the structure rotation angle; the phase value at each position is divided by 2 to obtain the rotation angle of the nanorod at each position, that is, the unit structure arrangement of the metasurface is obtained from the phase gradient distribution.

[0017] The implementation method of the wavefront manipulation function is as follows: different phase distributions are introduced through the metasurface to realize specific wavefront manipulation, and the wavefront manipulation includes superlenses, holographic imaging, generation of vortex beams, generation of special beams, and abnormal deflection.

[0018] The beneficial effects of the present application are as follows: 1. The present application utilizes the local effect and non-local effect of the subwavelength periodic unit structure to provide a design method of a non-crosstalk metasurface with wavefront manipulation function and beam deflection function multiplexing. The design method provided by the present application first obtains the optimal length and width parameters of the metal nanorod and gives the unit arrangement corresponding to the wavefront manipulation function. When linearly polarized light with a wavelength of λ1 is obliquely incident on the metasurface, the energy of the outgoing light is concentrated in the-1 order diffraction order, that is, effective beam deflection is realized; when circularly polarized light with a wavelength of λ2 is normally incident on the metasurface, the 0 order diffraction light carries the designed wavefront manipulation function. Since the wavefront manipulation and abnormal deflection are realized based on different effects, the two functions work at different wavelengths, different diffraction orders and different outgoing directions, that is, the non-crosstalk design between the functions can be realized.

[0019] 2. The design method of the non-crosstalk multiplexing metasurface provided by the present application is simple and effective.

[0020] 3、The super surface designed in the application has the advantages of flexible design, mature process and easy integration. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0022] Figure 1 The flowchart of the present application.

[0023] Figure 2 The side view of the super surface unit structure of the present application.

[0024] Figure 3 The top view of the super surface unit structure of the present application.

[0025] Figure 4 The-1 order diffraction efficiency spectrum of the super surface of the present application at 45° oblique incidence corresponding to different unit structures.

[0026] Figure 5 The change relationship diagram of the cross-polar reflectivity and the corresponding phase of the super surface of the present application with the rotation angle of the unit structure when the incident light is normally incident.

[0027] Figure 6 The "S" picture of the holographic imaging of the present application.

[0028] Figure 7 The holographic image obtained by the super surface of the present application when the incident light is normally incident. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0030] Embodiment 1

[0031] A design method for realizing a non-crosstalk multiplexing super surface, as shown in Figure 1 , includes the following steps:

[0032] Step one, design the unit structure of the metasurface, optimize and adjust the size of the unit structure, screen out the unit structure parameters that make the cross-polarization reflectivity of the metasurface higher than 50% when the circularly polarized light is vertically incident, and form a unit structure parameter group A. The unit structure of the metasurface is an anisotropic nanorod structure, and the metasurface unit structure includes a metal nanorod, a dielectric layer, and a metal layer arranged in turn from top to bottom. The metal nanorod is a cuboid. The metal nanorod and the metal layer are made of gold, silver, copper, aluminum, chromium, or a combination of any two or more materials, and the dielectric layer is made of titanium oxide, silicon oxide, zinc oxide, aluminum oxide, or a combination of any two or more materials. The method for optimizing and adjusting the size of the unit structure is: vertically incident circularly polarized light on the metasurface, adjusting the length and width parameters of the metal nanorod, obtaining the cross-polarization reflectivity under different length and width parameters of the metal nanorod, determining the length and width parameter group with cross-polarization reflectivity higher than 50%, and determining the corresponding unit structure parameter group A.

[0033] Step two, screen the unit structure parameter group A obtained in step one, select the unit structure parameters that make the -1 order diffraction efficiency of the metasurface higher than 50% when linearly polarized light is obliquely incident, and form a unit structure parameter group B. The method for screening the unit structure parameters that make the -1 order diffraction efficiency of the metasurface higher than 50% when linearly polarized light is obliquely incident is: obliquely incident linearly polarized light on the metasurface, adjusting the length and width parameters of the metal nanorod determined in step one, obtaining the diffraction efficiency of the metal nanorod at different length and width parameters, screening the length and width parameter group with -1 order diffraction efficiency higher than 50%, and determining the corresponding unit structure parameter group B.

[0034] Step three, rotate the unit structure, and screen the unit structure parameter group B again, screen the unit structure parameters that make the -1 order diffraction efficiency of the metasurface still higher than 50% when linearly polarized incident light is obliquely incident at different rotation angles, and determine the unit structure parameters with the highest -1 order diffraction efficiency as the optimal unit structure parameters. The method for screening the unit structure parameter group B again is: rotating the unit structure by different angles, obliquely incident linearly polarized light on the metasurface, adjusting the length and width parameter group of the metal nanorod screened in step two, obtaining the -1 order diffraction efficiency of the metal nanorod at different rotation angles, screening the length and width parameter group of the metal nanorod with -1 order diffraction efficiency higher than 50% at each rotation angle, and finally determining an optimal length and width parameter of the metal nanorod.

[0035] Step four, based on the optimal parameter unit structure, the wavefront manipulation super surface is designed, and the corresponding phase distribution is obtained, and the unit structure arrangement of the super surface is determined by the phase gradient distribution. Among them, the method for designing a super surface with a specific wavefront manipulation function is: designing a wavefront manipulation function, obtaining the corresponding phase gradient distribution; the phase is realized based on the geometric phase, and the geometric phase is carried by the cross-polarized circular polarization component and is twice the structure rotation angle; the phase value of each position is divided by 2, and the rotation angle of the nanorod at each position is obtained, that is, the unit structure arrangement of the super surface is obtained from the phase gradient distribution. In addition, the implementation method of the wavefront manipulation function is: different phase distributions are introduced through the super surface to realize specific wavefront manipulation, and the wavefront manipulation includes super lens, holographic imaging, vortex beam generation, special beam generation, and abnormal deflection.

[0036] Step five, the incident light is incident to the super surface at different incident angles, polarizations and wavelengths, and the wavefront manipulation function and the beam deflection function are obtained. When the circularly polarized light is vertically incident, the super surface has a wavefront manipulation function; when the linearly polarized light is obliquely incident, the grating diffraction effect based on the overall unit structure and the local effect of the unit structure act together to suppress other diffraction orders except-1 diffraction order, realize the super grating with-1 order diffraction as the main, that is, realize the beam deflection function. When the circularly polarized light is vertically incident to the super surface corresponding to the optimal length and width parameters, the working wavelength with the highest circular polarization conversion efficiency is recorded as λ1; when the linearly polarized light is obliquely incident to the super surface corresponding to the optimal length and width parameters, the working wavelength with the highest-1 order diffraction efficiency is recorded as λ2. The reason why there is no crosstalk between the wavefront manipulation and the beam deflection function is that: the wavefront manipulation super surface is based on the local effect to realize the wavefront manipulation of a certain phase distribution on the 0 order diffraction light, the super grating is based on the local effect and the grating diffraction effect to make the outgoing energy concentrate on a certain diffraction order to realize the beam deflection, and the certain diffraction order is generally positive or negative 1 order, and the two functions work in different diffraction orders and have obvious differences in working wavelength, so there is no crosstalk. The design method proposed in the application is simple, flexible, mature and effective.

[0037] Embodiment 2

[0038] A design method for realizing a non-crosstalk multiplexing super surface, step one: design and optimize the unit structure of the super surface, so that the super surface has a cross-polarized reflectivity higher than 50% when the circularly polarized incident light is vertically incident.

[0039] As Figure 2 With Figure 3As shown, the unit structure of the metasurface is sequentially provided from top to bottom as a metal nanorod, a dielectric layer and a metal layer, the metal nanorod and the metal layer are both Au material, and the dielectric layer is SiO2 material. Among them, the long side of the unit structure is set as the x-direction side, and the wide side is set as the y-direction side. In this embodiment, the length of the single unit structure in the x-direction is 500 nm, the length in the y-direction is 400 nm, the thickness of the metal layer and the dielectric layer is both 100 nm, and the thickness of the metal nanorod is 60 nm. The length and width of the metal nanorod are scanned by using an electromagnetic simulation software, the scanning range of the length of the nanorod is set as 200-350 nm with a scanning step of 10 nm, and the scanning range of the width of the nanorod is set as 60-200 nm with a scanning step of 10 nm. The cross-polar reflectivity of the metasurface under different x-axis and y-axis lengths is compared, and the x-axis and y-axis length group with the metasurface having a cross-polar reflectivity higher than 50% is obtained, which constitutes the unit structure parameter group A.

[0040] Step two: screening the above unit structure parameter group A so that the metasurface has high-1 order diffraction efficiency when the linearly polarized light is obliquely incident, thereby determining a new x-axis and y-axis length group. The specific method is as follows: the unit structure in the unit structure parameter group A obtained in step one is simulated by using an electromagnetic simulation software, wherein the incident light is incident in the x-z plane, the angle with the z-axis is 45°, and the polarization direction is along the y direction. The diffraction efficiency of the metasurface under different x-axis and y-axis lengths is compared, and the unit structure parameter group B of the nanorod length and width parameter group with the-1 order diffraction efficiency higher than 50% is screened out.

[0041] Step three: rotating the unit structure in the unit structure parameter group B, and screening the x-axis and y-axis length parameters of the unit structure in the unit structure parameter group B again so that the metasurface under different rotation angles still has high-1 order diffraction efficiency when the linearly polarized incident light is obliquely incident, thereby determining the optimal x-axis and y-axis length. The specific method is as follows: the angle between the long side of the unit structure and the x-axis is set as α, the unit structure screened out in step two is rotated around the z-axis, the rotation angles α are respectively: 0°, 30°, 60°, 90°, and the metasurface corresponding to the unit structure is simulated by using an electromagnetic simulation software, wherein the parameters of the linearly polarized incident light used in step three are the same as those of the linearly polarized light in step two. The-1 order diffraction efficiency of the x and y axis length parameters under different rotation angles is obtained, the length and width parameter group of the metal nanorod with the-1 order diffraction efficiency higher than 50% under each rotation angle is screened out, and the optimal x-axis and y-axis length parameters are determined as 240 nm and 140 nm respectively. The linearly polarized light is obliquely incident on the metasurface corresponding to the optimal x-axis and y-axis length parameters, and the working wavelength with the highest-1 order diffraction efficiency is recorded as λ1. As shown in FIG. 2, the working wavelength λ1 is 650 nm. Figure 4As shown in the figure, when the x-axis and y-axis length parameters are 240nm and 140nm respectively, the metasurface at different rotation angles is dominated by -1 order diffraction at a wavelength of λ1=775nm, and other diffraction orders are effectively suppressed.

[0042] Step 4: Based on the optimal nanorod x-axis and y-axis lengths of 240nm and 140nm, a wavefront manipulation metasurface is designed and the corresponding phase arrangement is obtained. The unit structure arrangement of the metasurface is determined by the phase gradient arrangement. The method for realizing a metasurface with a specific wavefront manipulation function is as follows: designing the wavefront manipulation function and obtaining the corresponding phase gradient arrangement; the phase is realized based on the geometric phase, which is carried by the cross-polarized circular polarization component and is twice the rotation angle of the structure; dividing the phase value at each position by 2 can obtain the rotation angle of the nanorod at each position, and thus the unit structure arrangement of the metasurface.

[0043] In this embodiment, the x-axis length parameter and y-axis length parameter of the unit structure used are 240nm and 140nm respectively. The circularly polarized light is vertically incident on the metasurface corresponding to the optimal x-axis and y-axis length parameters. The working wavelength with the highest cross-polarization reflectivity is denoted as λ2. Its cross-polarization reflectivity at different rotation angles is shown as follows: Figure 5 As shown; geometric phase The relationship between the unit structure rotation angle θ(x,y) is like Figure 3 As shown in the figure, the designed wavefront manipulation function is holographic imaging. The target image selected is the "S" pattern, as shown in the figure. Figure 6 As shown. The GS algorithm is then used to obtain the phase distribution of the target image based on Fourier transform. By dividing the phase of each position in the target image by 2, the rotation angle of the unit structure at each position of the metasurface can be obtained.

[0044] Step 5: The incident light is incident on the metasurface at different incident angles, polarizations, and wavelengths to obtain the wavefront manipulation function and the beam deflection function. When the circularly polarized light is incident vertically, the metasurface has the wavefront manipulation function; when the linearly polarized light is incident obliquely, the grating diffraction effect based on the overall unit structure and the local effect of the unit structure work together to suppress the diffraction orders other than the -1 diffraction order, and realize the metagrating dominated by the -1 order diffraction, that is, the beam deflection function is realized. When the x-axis and y-axis length parameters of the unit structure are 240nm and 140nm, the metasurface at different rotation angles is dominated by the -1 order diffraction at a wavelength of λ1=775nm, and the phase is basically the same. Therefore, when the incident light is incident in the xz plane, the angle with the z-axis is 45° and it is polarized along the y direction, the angle between the -1 order diffraction direction and the z-axis is given by the grating equation P x (sinθ i +sinθ r) can be 53.42° and is located on the same side of the normal as the incident light, that is, high-efficiency and large-angle beam deflection is achieved. Wherein, P x is the period in the x direction, θ i is the incident angle, θ r is the-1 order diffraction angle. When the circularly polarized light is normally incident to the metasurface, the holographic image of λ2=1μm is obtained as shown in FIG. 2. Figure 7

[0045] At different incident angles and incident wavelengths, there is no crosstalk between the two functions, that is, a non-crosstalk multiplexing metasurface is achieved based on the local effect and the non-local effect, as shown in Table 1. The reason why there is no crosstalk between the wavefront manipulation and the beam deflection function is that the wavefront manipulation metasurface is based on the local effect to achieve a certain phase arrangement of the wavefront manipulation of the 0th order diffraction light, the supergrating is based on the local effect and the grating diffraction effect to make the outgoing energy concentrate on a certain diffraction order to achieve beam deflection, and the certain diffraction order is generally the positive and negative 1st order. The two functions work in different diffraction orders and have obvious differences in working wavelengths, so there is no crosstalk. The metasurface designed by using this method has mature technology and is easy to integrate.

[0046] Table 1.

[0047]

[0048] The other structures and principles are the same as those of Embodiment 1.

[0049] The above only describes the preferred embodiments of the present application and should not be used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.​

Claims

1. A design method for implementing non-crosstalk multiplexing metasurfaces, characterized by, The method comprises the following steps: Step one, designing a unit structure of the super surface, optimizing and adjusting the size of the unit structure, screening the unit structure parameters to make the cross-polarization reflectivity of the super surface higher than 50% when the circularly polarized light is vertically incident, and forming a unit structure parameter group A; The unit structure of the super surface is an anisotropic nanorod structure, and the unit structure of the super surface comprises metal nanorods, a dielectric layer and a metal layer arranged in sequence from top to bottom. Step two, screening the unit structure parameter group A obtained in step one, screening the unit structure parameters to make the -1 order diffraction efficiency of the super surface higher than 50% when the linearly polarized light is obliquely incident, and forming a unit structure parameter group B selected from the unit structure parameter group A. Step three, rotating the unit structure, screening the unit structure parameter group B again, screening the unit structure parameters to make the -1 order diffraction efficiency of the super surface still higher than 50% when the linearly polarized incident light is obliquely incident at different rotation angles, and determining the unit structure parameters with the highest -1 order diffraction efficiency as the optimal unit structure parameters. Step four, designing a wavefront manipulation super surface based on the unit structure with the optimal parameters, obtaining the corresponding phase arrangement, and determining the unit structure arrangement of the super surface by the phase gradient arrangement. Step five, making the incident light incident to the super surface at different incident angles, polarizations and wavelengths to obtain the wavefront manipulation function and the beam deflection function; when the circularly polarized light is vertically incident, the super surface has the wavefront manipulation function; when the linearly polarized light is obliquely incident, the grating diffraction effect of the overall unit structure and the local effect of the unit structure jointly act to suppress the diffraction orders other than the -1 diffraction order, so that the super grating mainly with the -1 diffraction order is realized, that is, the beam deflection function is realized.

2. The method of designing a non-crosstalk multiplexed metasurface according to claim 1, wherein, The metal nanorod is a cuboid.

3. The method of designing a non-crosstalk multiplexed metasurface according to claim 2, wherein, The metal nanorod and the metal layer are made of gold, silver, copper, aluminum, chromium or a combination of any two or more materials, and the dielectric layer is made of titanium oxide, silicon oxide, zinc oxide, aluminum oxide or a combination of any two or more materials.

4. The method of designing a non-crosstalk multiplexed metasurface according to claim 3, wherein, In step one, the method for optimizing and adjusting the size of the unit structure is as follows: making the circularly polarized light vertically incident on the super surface, adjusting the length and width parameters of the metal nanorod, obtaining the cross-polarization reflectivity under different length and width parameters of the metal nanorod, determining the length and width parameter group with the cross-polarization reflectivity higher than 50%, and determining the corresponding unit structure parameter group A.

5. The method of designing a non-crosstalk multiplexed metasurface of any of claims 2-4, wherein, In step two, the method for screening the unit structure parameters to make the -1 order diffraction efficiency of the super surface higher than 50% when the linearly polarized light is obliquely incident is as follows: making the linearly polarized light obliquely incident on the super surface, adjusting the length and width parameters of the metal nanorod determined in step one, obtaining the diffraction efficiency of each order of the metal nanorod under different length and width parameters of the nanorod, screening the length and width parameter group with the -1 order diffraction efficiency higher than 50%, and determining the corresponding unit structure parameter group B.

6. The method of designing a non-crosstalk multiplexed metasurface according to claim 5, wherein, The method for screening the unit structure parameter group B again in step three is: rotating the unit structure by different angles, adjusting the length and width parameter group of the metal nanorod screened in step two, obtaining the-1 order diffraction efficiency of the length and width parameter of the metal nanorod under different rotation angles, screening the length and width parameter group of the metal nanorod whose-1 order diffraction efficiency is higher than 50% under each rotation angle, and finally determining an optimal length and width parameter of the metal nanorod.

7. The method of designing a non-crosstalk multiplexed metasurface according to claim 6, wherein, The method for designing the metasurface with a specific wave front manipulation function in step four is: designing a wave front manipulation function to obtain a corresponding phase gradient arrangement; the phase is realized based on a geometric phase, the geometric phase is carried by cross-polarized circular polarization components and is twice the structure rotation angle; dividing the phase value of each position by 2 to obtain the rotation angle of the nanorod at each position, that is, obtaining the unit structure arrangement of the metasurface from the phase gradient arrangement.

8. The method of designing a non-crosstalk multiplexed metasurface according to claim 7, wherein, The implementation method of the wave front manipulation function is: introducing different phase arrangements through the metasurface to realize specific wave front manipulation, and the wave front manipulation includes superlens, holographic imaging, generation of vortex beams, generation of special beams and abnormal deflection.

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