Metastructure surface preparation method

Abstract

The invention relates to the technical field of metamaterials, in particular to a metasurface preparation method, which comprises the following steps: designing functional elements of a metasurface, imprinting the designed metasurface on a polymer through mechanical pressure by using a prefabricated mold, grinding and polishing the polymer, performing thermal shrinkage, and forming a metal metasurface through a metallization process. Calculating performance characterization parameters of the metasurface according to the decibel attenuation in combination with the air quantity passing through the metal metasurface, judging whether the performance of the metasurface meets the standard or not, adjusting the number, the size and the arrangement mode of local functional elements of the metasurface, and carrying out simulation testing to obtain the metasurface performance of the metasurface. According to the method, the reflectivity variation and the transmissivity variation before and after adjustment are calculated, coupling characterization parameters are calculated according to the reflectivity variation and the transmissivity variation before and after adjustment, the metasurface types are divided according to the coupling characterization parameters, and the adjustment mode of the functional elements is selected. The interaction among the functional elements forming the metasurface is considered, so that the prepared metasurface is high in efficiency and good in performance. And a preset sound field regulation and control function is not deviated.

Description

Technical Field

[0001] The present invention relates to the technical field of metamaterials, and in particular to a method for preparing a metastructured surface. Background Art

[0002] The preparation of metasurfaces integrates micro-nano processing technology, material science, precision engineering and modern design theory. These technologies allow researchers to design and manufacture metasurfaces with specific electromagnetic responses, and to manipulate light or sound waves by precisely controlling their microstructures. Micro-nano processing technologies, such as electron beam lithography (EBL), focused ion beam etching (FIB), nanoimprint lithography (NIL) and laser direct writing, provide high-precision patterning methods for metasurfaces. Materials science focuses on selecting and synthesizing materials suitable for specific applications, such as metals, semiconductors, insulators and special polymers. Precision engineering ensures the accuracy and repeatability of the processing process to meet the strict requirements of metasurfaces for dimensional accuracy. Modern design theory, including computer-aided design (CAD) and simulation software, enables designers to predict and optimize the performance of metasurfaces before manufacturing. The comprehensive application of these background technologies has promoted the rapid development and innovation of metasurfaces in the fields of optics, acoustics, stealth technology, etc.

[0003] Chinese patent publication number: CN116722368A, discloses a super surface structure and its preparation method. The preparation method of this application adopts a combination of hot pressing and heat shrinking, including: template design, hot pressing, grinding, heat shrinking, and gold plating. Through the design of the template, after hot pressing and heat shrinking, a super surface structure with a higher aspect ratio can be obtained simply and efficiently.

[0004] However, there are still the following problems in the prior art:

[0005] In the prior art, the interaction between the functional elements that constitute the metasurface is not taken into consideration, the functional elements are not adjusted according to the strength of the interaction between the functional elements, and the interaction between the functional elements is ignored, resulting in a significant reduction in the efficiency of the designed metasurface and deviation from the preset sound field control function. Summary of the invention

[0006] To this end, the present invention provides a metasurface preparation method to overcome the problems in the prior art that the interaction between functional elements constituting the metasurface is not considered, the functional elements are not adjusted according to the strength of the interaction between the functional elements, and the interaction between the functional elements is ignored, resulting in a significant reduction in the efficiency of the designed metasurface and deviation from the preset sound field control function.

[0007] To achieve the above object, the present invention provides a method for preparing a metasurface, comprising:

[0008] Step S1, designing the number, size and arrangement of metasurface functional primitives;

[0009] Step S2, using a prefabricated mold to imprint the designed metasurface on a polymer by mechanical pressure, grinding and polishing the polymer and then heat shrinking it to obtain the metasurface to be metallized;

[0010] Step S3, forming a metal metasurface through a metallization process on the metasurface to be metallized;

[0011] Step S4, applying a preset decibel sound source on one side of the metal metasurface, receiving the sound source on the other side of the metasurface, calculating the decibel attenuation, forming a preset pressure difference on both sides of the metal metasurface, measuring the amount of air passing through the metal metasurface within a preset time, and calculating the metasurface performance characterization parameter according to the decibel attenuation combined with the amount of air passing through the metal metasurface;

[0012] Step S5, judging whether the performance of the metasurface meets the standard according to the metasurface performance characterization parameter;

[0013] Step S6, adjusting the number, size and arrangement of local functional primitives of the metasurface, performing simulation tests, dividing the metasurface into several regions, and obtaining the reflectivity and transmittance of the regions where the functional primitives are not adjusted at a specific wavelength;

[0014] Step S7, calculating coupling characterization parameters according to the reflectivity change and transmittance change before and after the adjustment, classifying the metasurface according to the coupling characterization parameters, and selecting the adjustment method for the functional element, including:

[0015] The global functional primitives need to be adjusted;

[0016] Or, local functional primitives need to be adjusted.

[0017] Furthermore, in the step S3, the metastructure surface to be metallized is subjected to a metallization process to form a metal metastructure surface, wherein the metallization process is to use an ion beam to perform gold plating on the metastructure surface to be metallized.

[0018] Furthermore, in step S4, the process of calculating the decibel attenuation includes:

[0019] Get the preset decibel level applied;

[0020] Get the decibel level of the received sound source;

[0021] The difference between the applied preset decibel level and the decibel level of the received sound source is the decibel attenuation.

[0022] Furthermore, in step S4, the metasurface performance characterization parameter is calculated according to formula (1):

[0023]

[0024] In formula (1), C represents the parameter characterizing the performance of the metasurface, dB represents the decibel attenuation, dB0 represents the preset decibel attenuation threshold, Q represents the amount of air passing through the metal metasurface, and Q0 represents the preset threshold for the amount of air passing through the metal metasurface.

[0025] Furthermore, in step S5, the process of determining whether the performance of the metasurface meets the standard according to the metasurface performance characterization parameter includes:

[0026] Compare the metasurface performance characterization parameters with the preset metasurface performance characterization parameter comparison threshold,

[0027] If the metasurface performance characterization parameter is greater than a preset metasurface performance characterization parameter comparison threshold, the metasurface performance is determined to meet the standard;

[0028] If the metasurface performance characterization parameter is less than or equal to a preset metasurface performance characterization parameter comparison threshold, it is determined that the metasurface performance does not meet the standard.

[0029] Furthermore, in step S6, the metasurface is divided into a plurality of regions, wherein the area of ​​each region is equal.

[0030] Furthermore, in step S7, the process of obtaining the reflectivity change amount and the transmittance change amount before and after the adjustment includes:

[0031] Obtain the reflectivity and transmittance of each area of ​​the metasurface;

[0032] Screening the area where the functional primitives have not been adjusted, and obtaining the reflectivity and transmittance of the area where the functional primitives have not been adjusted before and after the adjustment;

[0033] Calculate the difference between the reflectivity of the region without functional primitive adjustment before and after adjustment, and the difference between the transmittance of the region without functional primitive adjustment before and after adjustment;

[0034] The average value of the difference in reflectivity of the regions where the functional element adjustment is not performed is recorded as the reflectivity change, and the average value of the difference in transmittance of the regions where the functional element adjustment is not performed is recorded as the transmittance change.

[0035] Furthermore, in step S7, the coupling characterization parameter is calculated according to formula (2):

[0036]

[0037] In formula (2), L represents the coupling characterization parameter, Pf represents the reflectivity change, Pf0 represents the preset reflectivity change threshold, Pt represents the transmittance change, and Pt0 represents the preset transmittance change threshold.

[0038] Furthermore, in step S7, the metasurfaces are classified according to the coupling characterization parameters.

[0039] Compare the coupling characterization parameter with the preset coupling characterization parameter comparison threshold,

[0040] If the coupling characterization parameter is less than the preset coupling characterization parameter comparison threshold, the metasurface category is a weak coupling category;

[0041] If the coupling characterization parameter is greater than or equal to a preset coupling characterization parameter comparison threshold, the metasurface category is a strong coupling category.

[0042] Furthermore, in step S7, a method for adjusting the functional primitive is selected, wherein:

[0043] If the metasurface category is a weak coupling category, the local functional primitives are adjusted;

[0044] If the metasurface category is a strong coupling category, the global functional primitives need to be adjusted.

[0045] Compared with the prior art, the present invention designs metasurface functional elements, uses a prefabricated mold to imprint the designed metasurface on a polymer through mechanical pressure, grinds and polishes the polymer and then heat shrinks it, forms a metal metasurface through a metallization process, calculates metasurface performance characterization parameters based on decibel attenuation combined with the amount of air passing through the metal metasurface, determines whether the metasurface performance meets the standard, adjusts the number, size and arrangement of local functional elements on the metasurface, conducts simulation tests, calculates coupling characterization parameters based on the change in reflectivity and transmittance before and after adjustment, divides the metasurface into categories based on the coupling characterization parameters, and selects the adjustment method for the functional elements. The present invention considers the interaction between the functional elements constituting the metasurface, so that the prepared metasurface is highly efficient and does not deviate from the preset sound field control function.

[0046] In particular, the present invention calculates a metasurface performance characterization parameter based on the decibel attenuation combined with the amount of air passing through the metal metasurface. The sound insulation and air permeability of the metasurface are important influencing parameters for characterizing whether the metasurface meets the preparation standards. In order to ensure that the metasurface has both sound insulation and air permeability, the decibel attenuation is combined with the amount of air passing through the metal metasurface. The metasurface performance characterization parameter obtained can characterize the sound insulation and air permeability of the metasurface, reliably evaluate the metasurface performance, and provide data support for the follow-up.

[0047] In particular, the present invention calculates the coupling characterization parameters according to the change in reflectivity and transmittance before and after adjustment. If each functional unit is designed locally and there is no coupling between them, the sound field can be controlled by adjusting the phase and amplitude response of each functional unit. If there is interaction between each functional unit, the mutual coupling of the functional units cannot be ignored. The present invention can obtain the degree of interaction between the functional units by obtaining the change in reflectivity and transmittance, thereby providing data support for the adjustment of the functional units, so that the efficiency of the designed metasurface is improved without deviating from the preset sound field control function.

[0048] In particular, the present invention classifies metasurfaces according to coupling characterization parameters and selects adjustment methods for functional primitives. When the reflectivity change and the refractive index change before and after the adjustment are large, it can be characterized to a certain extent that there is a strong coupling effect between the functional primitives. When the reflectivity change and the refractive index change before and after the adjustment are small, it can be characterized to a certain extent that there is a weak coupling effect between the functional primitives. By classifying the metasurfaces, when there is a weak coupling effect between the functional primitives, the local functional primitives can be adjusted. When there is a strong coupling effect between the functional primitives, the global functional primitives need to be adjusted, so that the efficiency of the designed metasurface is improved without deviating from the preset sound field control function. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A step diagram of a method for preparing a metasurface according to an embodiment of the invention;

[0050] Figure 2 A logical decision diagram for determining whether the performance of a metasurface meets the standard according to an embodiment of the invention;

[0051] Figure 3 A logic decision diagram for classifying metasurface categories according to coupling characterization parameters of an embodiment of the invention;

[0052] Figure 4 A diagram is provided for selecting a method for adjusting functional primitives according to an embodiment of the invention. DETAILED DESCRIPTION

[0053] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0055] See also Figure 1-Figure 4 As shown, Figure 1This is a step diagram of the method for preparing a metasurface according to an embodiment of the invention. Figure 2 The logic decision diagram for determining whether the performance of the metasurface meets the standard is provided in the embodiment of the invention. Figure 3 It is a logic decision diagram for classifying the metasurface categories according to the coupling characterization parameters of the embodiment of the invention. Figure 4 The method for preparing a metasurface of the present invention comprises:

[0056] Step S1, designing the number, size and arrangement of metasurface functional primitives;

[0057] Step S2, using a prefabricated mold to imprint the designed metasurface on a polymer by mechanical pressure, grinding and polishing the polymer and then heat shrinking it to obtain the metasurface to be metallized;

[0058] Step S3, forming a metal metasurface through a metallization process on the metasurface to be metallized;

[0059] Step S4, applying a preset decibel sound source on one side of the metal metasurface, receiving the sound source on the other side of the metasurface, calculating the decibel attenuation, forming a preset pressure difference on both sides of the metal metasurface, measuring the amount of air passing through the metal metasurface within a preset time, and calculating the metasurface performance characterization parameter according to the decibel attenuation combined with the amount of air passing through the metal metasurface;

[0060] Step S5, judging whether the performance of the metasurface meets the standard according to the metasurface performance characterization parameter;

[0061] Step S6, adjusting the number, size and arrangement of local functional primitives of the metasurface, performing simulation tests, dividing the metasurface into several regions, and obtaining the reflectivity and transmittance of the regions where the functional primitives are not adjusted at a specific wavelength;

[0062] Step S7, calculating coupling characterization parameters according to the reflectivity change and transmittance change before and after the adjustment, classifying the metasurface according to the coupling characterization parameters, and selecting the adjustment method for the functional element, including:

[0063] The global functional primitives need to be adjusted;

[0064] Or, local functional primitives need to be adjusted.

[0065] Specifically, in step S3, the metastructure surface to be metallized is subjected to a metallization process to form a metal metastructure surface, wherein the metallization process is to use an ion beam to perform gold plating on the metastructure surface to be metallized.

[0066] Specifically, in this embodiment, computer-aided design software, optionally CAD, is used to create two-dimensional or three-dimensional design drawings of metasurface functional elements.

[0067] Specifically, in this embodiment, the electromagnetic simulation software may be CST (Computer Simulation Technology), which can provide modeling and analysis functions for metasurfaces, including simulation of reflectivity and refractive index. CST can be used to perform geometric modeling and electromagnetic field simulation of metasurfaces, and MATLAB can be used to perform more complex algorithms and numerical calculations to achieve precise control of the reflection, transmission, focusing, and scattering characteristics of incident waves.

[0068] In this embodiment, the prefabricated mold is made of a high-hardness, high-wear-resistant material, which may be quartz, silicon, stainless steel or a special alloy.

[0069] In this embodiment, a polymer with good thermal stability and mechanical properties is selected, such as PMMA (polymethyl methacrylate), PDMS (polydimethylsiloxane), SU-8 (an epoxy resin), etc.

[0070] In this embodiment, the imprinted polymer surface may need to be ground and polished to remove excess material and smooth the surface. This can be achieved by mechanical polishing, chemical mechanical polishing (CMP), or local polishing using an atomic force microscope (AFM).

[0071] It can be understood that the functional elements of the metasurface are the basic units that constitute the metasurface. They are artificially designed and arranged in a specific space to achieve the regulation of electromagnetic waves (including visible light, near-infrared light, terahertz, microwave and other bands).

[0072] Specifically, in step S4, the process of calculating the decibel attenuation includes:

[0073] Get the preset decibel level applied;

[0074] Get the decibel level of the received sound source;

[0075] The difference between the applied preset decibel level and the decibel level of the received sound source is the decibel attenuation.

[0076] In this embodiment, the preset decibel dBy value applied is selected within the range of [60dB, 100dB].

[0077] Specifically, in step S4, the metasurface performance characterization parameter is calculated according to formula (1):

[0078]

[0079] In formula (1), C represents the parameter characterizing the performance of the metasurface, dB represents the decibel attenuation, dB0 represents the preset decibel attenuation threshold, Q represents the amount of air passing through the metal metasurface, and Q0 represents the preset threshold for the amount of air passing through the metal metasurface.

[0080] In this embodiment, dB0 is selected within the range of [0.7dBy, 0.8dBy], Q0 is measured in advance by experiments, the air permeability of several walls is tested in advance, a preset pressure difference is formed on both sides of several walls, the amount of air passing through the wall within a preset time is measured, and the average air volume Qe is calculated. It is assumed that Q0 = a × Qe, 1.2 < a < 1.3, a is the air volume coefficient, the preset pressure difference is 0.1 MPa, and the preset time is 5 min.

[0081] Specifically, the present invention calculates a metasurface performance characterization parameter based on the decibel attenuation combined with the amount of air passing through the metal metasurface. The sound insulation and air permeability of the metasurface are important influencing parameters for characterizing whether the metasurface meets the preparation standards. In order to ensure that the metasurface has both sound insulation and air permeability, the decibel attenuation is combined with the amount of air passing through the metal metasurface. The metasurface performance characterization parameter obtained can characterize the sound insulation and air permeability of the metasurface, reliably evaluate the metasurface performance, and provide data support for the follow-up.

[0082] Specifically, in step S5, the process of determining whether the performance of the metasurface meets the standard according to the metasurface performance characterization parameter includes:

[0083] Compare the metasurface performance characterization parameters with the preset metasurface performance characterization parameter comparison threshold,

[0084] If the metasurface performance characterization parameter is greater than a preset metasurface performance characterization parameter comparison threshold, the metasurface performance is determined to meet the standard;

[0085] If the metasurface performance characterization parameter is less than or equal to a preset metasurface performance characterization parameter comparison threshold, it is determined that the metasurface performance does not meet the standard.

[0086] In this embodiment, the preset metasurface performance characterization parameter comparison threshold is selected within the range of [1.55, 1.60].

[0087] It is understandable that the present invention performs step S6 and step S7 when it is determined that the performance of the metasurface does not meet the standard.

[0088] Specifically, in step S6, the metasurface is divided into a number of regions, wherein the area of ​​each region is equal.

[0089] Specifically, in step S7, the process of obtaining the reflectivity change amount and the transmittance change amount before and after adjustment includes:

[0090] Obtain the reflectivity and transmittance of each area of ​​the metasurface;

[0091] Screening the area where the functional primitives have not been adjusted, and obtaining the reflectivity and transmittance of the area where the functional primitives have not been adjusted before and after the adjustment;

[0092] Calculate the difference between the reflectivity of the region without functional primitive adjustment before and after adjustment, and the difference between the transmittance of the region without functional primitive adjustment before and after adjustment;

[0093] The average value of the difference in reflectivity of the regions where the functional element adjustment is not performed is recorded as the reflectivity change, and the average value of the difference in transmittance of the regions where the functional element adjustment is not performed is recorded as the transmittance change.

[0094] Specifically, in step S7, the coupling characterization parameter is calculated according to formula (2):

[0095]

[0096] In formula (2), L represents the coupling characterization parameter, Pf represents the reflectivity change, Pf0 represents the preset reflectivity change threshold, Pt represents the transmittance change, and Pt0 represents the preset transmittance change threshold.

[0097] In this embodiment, Pf0 is selected within the range of [10%, 20%], and Pt0 is selected within the range of [10%, 20%].

[0098] Specifically, the present invention calculates the coupling characterization parameters according to the change in reflectivity and transmittance before and after adjustment. If each functional unit is designed locally and there is no coupling between them, the sound field can be controlled by adjusting the phase and amplitude response of each functional unit. If there is interaction between each functional unit, the mutual coupling of the functional units cannot be ignored. The present invention can obtain the degree of interaction between the functional units by obtaining the change in reflectivity and transmittance, thereby providing data support for the adjustment of the functional units, so that the efficiency of the designed metasurface is improved without deviating from the preset sound field control function.

[0099] Specifically, in step S7, the metasurface categories are divided according to the coupling characterization parameters.

[0100] Compare the coupling characterization parameter with the preset coupling characterization parameter comparison threshold,

[0101] If the coupling characterization parameter is less than the preset coupling characterization parameter comparison threshold, the metasurface category is a weak coupling category;

[0102] If the coupling characterization parameter is greater than or equal to a preset coupling characterization parameter comparison threshold, the metasurface category is a strong coupling category.

[0103] In this embodiment, the preset coupling characterization parameter comparison threshold is selected within the range of [1.55, 1.60].

[0104] Specifically, in step S7, a method for adjusting the functional primitive is selected, wherein:

[0105] If the metasurface category is a weak coupling category, the local functional primitives are adjusted;

[0106] If the metasurface category is a strong coupling category, the global functional primitives need to be adjusted.

[0107] It can be understood that the functional element is adjusted to change the basic characteristics of the local functional unit, such as size, quantity, etc., thereby affecting its resonant frequency and the coupling strength of the electromagnetic wave, thereby changing the phase and amplitude. The phase and amplitude can be obtained through electromagnetic field simulation, which will not be repeated here.

[0108] Specifically, the present invention classifies metasurfaces according to coupling characterization parameters, and selects adjustment methods for functional primitives. When the change in reflectivity and the change in refractive index before and after adjustment are large, it can be characterized to a certain extent that there is a strong coupling effect between the functional primitives. When the change in reflectivity and the change in refractive index before and after adjustment are small, it can be characterized to a certain extent that there is a weak coupling effect between the functional primitives. By classifying metasurfaces, when there is a weak coupling effect between functional primitives, local functional primitives can be adjusted, and when there is a strong coupling effect between functional primitives, global functional primitives can be adjusted, so that the efficiency of the designed metasurface is improved without deviating from the preset sound field control function.

[0109] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for preparing a metasurface, characterized in that: include: Step S1, designing the number, size and arrangement of metasurface functional primitives; Step S2, using a prefabricated mold to imprint the designed metasurface on a polymer by mechanical pressure, grinding and polishing the polymer and then heat shrinking it to obtain the metasurface to be metallized; Step S3, forming a metal metasurface through a metallization process on the metasurface to be metallized; Step S4, applying a preset decibel sound source on one side of the metal metasurface, receiving the sound source on the other side of the metasurface, calculating the decibel attenuation, forming a preset pressure difference on both sides of the metal metasurface, measuring the amount of air passing through the metal metasurface within a preset time, and calculating the metasurface performance characterization parameter according to the decibel attenuation combined with the amount of air passing through the metal metasurface; Step S5, judging whether the performance of the metasurface meets the standard according to the metasurface performance characterization parameter; Step S6, adjusting the number, size and arrangement of local functional primitives of the metasurface, performing simulation tests, dividing the metasurface into several regions, and obtaining the reflectivity and transmittance of the regions where the functional primitives are not adjusted at a specific wavelength; Step S7, calculating coupling characterization parameters according to the reflectivity change and transmittance change before and after the adjustment, classifying the metasurface according to the coupling characterization parameters, and selecting the adjustment method for the functional element, including: The global functional primitives need to be adjusted; Or, local functional primitives need to be adjusted.

2. The method for preparing a metasurface according to claim 1, characterized in that: In the step S3, the metastructure surface to be metallized is subjected to a metallization process to form a metal metastructure surface, wherein the metallization process is to use an ion beam to perform gold plating on the metastructure surface to be metallized.

3. The method for preparing a metasurface according to claim 1, characterized in that: In step S4, the process of calculating the decibel attenuation includes: Get the preset decibel level applied; Get the decibel level of the received sound source; The difference between the applied preset decibel level and the decibel level of the received sound source is the decibel attenuation.

4. The method for preparing a metasurface according to claim 1, characterized in that: In step S4, the metasurface performance characterization parameter is calculated according to formula (1): In formula (1), C represents the parameter characterizing the performance of the metasurface, dB represents the decibel attenuation, dB0 represents the preset decibel attenuation threshold, Q represents the amount of air passing through the metal metasurface, and Q0 represents the preset threshold for the amount of air passing through the metal metasurface.

5. The method for preparing a metasurface according to claim 4, characterized in that: In step S5, the process of determining whether the performance of the metasurface meets the standard according to the metasurface performance characterization parameter includes: Compare the metasurface performance characterization parameters with the preset metasurface performance characterization parameter comparison threshold, If the metasurface performance characterization parameter is greater than a preset metasurface performance characterization parameter comparison threshold, the metasurface performance is determined to meet the standard; If the metasurface performance characterization parameter is less than or equal to a preset metasurface performance characterization parameter comparison threshold, it is determined that the metasurface performance does not meet the standard.

6. The method for preparing a metasurface according to claim 1, characterized in that: In step S6, the metasurface is divided into a plurality of regions, wherein the area of ​​each region is equal.

7. The method for preparing a metasurface according to claim 1, characterized in that: In step S7, the process of obtaining the reflectivity change amount and the transmittance change amount before and after adjustment includes: Obtain the reflectivity and transmittance of each area of ​​the metasurface; Screening the area where the functional primitives have not been adjusted, and obtaining the reflectivity and transmittance of the area where the functional primitives have not been adjusted before and after the adjustment; Calculate the difference between the reflectivity of the region without functional primitive adjustment before and after adjustment, and the difference between the transmittance of the region without functional primitive adjustment before and after adjustment; The average value of the difference in reflectivity of the regions where the functional element adjustment is not performed is recorded as the reflectivity change, and the average value of the difference in transmittance of the regions where the functional element adjustment is not performed is recorded as the transmittance change.

8. The method for preparing a metasurface according to claim 1, characterized in that: In step S7, the coupling characterization parameter is calculated according to formula (2): In formula (2), L represents the coupling characterization parameter, Pf represents the reflectivity change, Pf0 represents the preset reflectivity change threshold, Pt represents the transmittance change, and Pt0 represents the preset transmittance change threshold.

9. The method for preparing a metasurface according to claim 8, characterized in that: In the step S7, the metasurface is classified according to the coupling characterization parameter. Compare the coupling characterization parameter with the preset coupling characterization parameter comparison threshold, If the coupling characterization parameter is less than the preset coupling characterization parameter comparison threshold, the metasurface category is a weak coupling category; If the coupling characterization parameter is greater than or equal to a preset coupling characterization parameter comparison threshold, the metasurface category is a strong coupling category.

10. The method for preparing a metasurface according to claim 9, characterized in that: In step S7, a method for adjusting the functional primitive is selected, wherein: If the metasurface category is a weak coupling category, the local functional primitives need to be adjusted; If the metasurface category is a strong coupling category, the global functional primitives need to be adjusted.

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