An electro-reconfigurable metasurface and its preparation method

Abstract

This invention discloses an electro-reconfigurable metasurface and its fabrication method. The metasurface includes a voltage source and multiple subwavelength units. Each subwavelength unit includes a substrate, a dielectric layer, a nano-metal grating, a phase change material layer filling the gaps between the nano-metal gratings, and an anti-oxidation layer. By adjusting the structural parameters of the nano-metal gratings and the phase change material layer, as well as the thickness of the anti-oxidation layer, different structural colors within the visible spectrum can be modulated. The structural parameters of the nano-metal grating include the grating thickness, period, and duty cycle. The duty cycle is the ratio of the grating width to the period within one period, and the width is smaller than the wavelength of the external incident light. The phase change material layer includes both amorphous and crystalline phases. The phase transition of the phase change material layer is achieved by adjusting the pulse width and voltage amplitude generated by the voltage source connected to the dielectric layer, which is used to achieve grayscale modulation of the color. This invention can not only modulate stable structural colors but also quickly and effectively adjust the grayscale of colors.

Description

Technical Field

[0001] This invention belongs to the field of electrically tunable metasurfaces, and more specifically, relates to an electro-reconfigurable metasurface and its preparation method. Background Technology

[0002] Metasurfaces or metamaterials are two-dimensional array surfaces at the micro-nano scale. They are planar structures composed of artificially arranged subwavelength units in a periodic or non-periodic manner. By changing the geometry or arrangement of the subwavelength units, the amplitude, phase, or polarization properties of incident electromagnetic waves can be modulated.

[0003] However, traditional metasurface structures, limited by their fixed size after fabrication, can only achieve single-function optical control for specific incident light. In the past decade or so, the rapid development of modern optoelectronic technology has continuously increased the demand for dynamic optical adjustment. People are no longer satisfied with single-function metasurfaces and hope to design dynamically tunable and reconfigurable metasurfaces.

[0004] To date, there is still a lack of research on electro-reconfigurable metasurfaces that can adjust the color of light in the visible spectrum and dynamically and reversibly adjust the gray level of the color, as well as their fabrication methods. This is an area that urgently needs to be studied and has high research and application value. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an electro-reconfigurable metasurface and its preparation method, which can not only adjust the stable structural color, but also quickly and reversibly adjust the grayscale of the color.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an electro-reconfigurable metasurface for stable adjustment of structural colors in the visible spectrum and dynamic reversible adjustment of the grayscale of the colors, comprising a voltage source and a plurality of periodically arranged subwavelength units, wherein the number of the subwavelength units is at least four, and each subwavelength unit comprises, from bottom to top, a substrate, a dielectric layer, a nano-metal grating, a phase change material layer filling the gaps between the nano-metal gratings, and an anti-oxidation layer, wherein the voltage source is connected to both ends of the dielectric layer;

[0007] The structural color within the visible spectrum is achieved by modulating the position of the resonant wavelength and the size of the absorption peak within the visible spectrum. The position of the resonant wavelength and the size of the absorption peak are achieved by adjusting the structural parameters of the nano-metal grating and the phase change material layer, as well as the thickness of the anti-oxidation layer. The structural parameters of the nano-metal grating include the grating thickness, period, and duty cycle. The duty cycle is the ratio of the grating width to the period within one period, and the width is less than the wavelength of the external incident light. The phase change material layer is made of chalcogenide phase change material or vanadium oxide material, including both amorphous and crystalline phases. The thickness of the phase change material layer is greater than 10 nm and less than or equal to 50 nm. The phase transition of the phase change material layer is achieved by adjusting the pulse width and voltage amplitude generated by the voltage source. The phase transition of the phase change material layer is used to achieve grayscale modulation of the color.

[0008] The electro-reconfigurable metasurface provided by this invention has the following effects: (1) By adjusting the structural parameters of the metal grating and the phase change material layer filling the gap between the gratings, as well as the thickness of the anti-oxidation layer, the position of the resonance wavelength and the size of the absorption peak can be modulated, thereby achieving stable adjustment of the structural color in the visible spectrum range; (2) By using phase change material to fill the gap between the metal gratings, and taking advantage of the significant difference in photoelectric properties of the phase change material before and after the phase transition, the grayscale of the resulting structural color can be changed, thereby achieving dynamic and reversible adjustment of the grayscale of the color; (3) The structural color generated by the local surface plasmon resonance of this invention is a physical color generated by a physical phenomenon, which is different from the chemical color generated by dyes. It is stable in nature, and the anti-oxidation layer on top of the metal grating and the phase change material provides anti-oxidation protection for the structure, further stabilizing the properties of the structural color. The structural color generated by this electro-reconfigurable metasurface has the advantages of non-volatility, anti-oxidation, low crosstalk, and low power consumption, and the grayscale of the structural color can be quickly and reversibly adjusted, which has great application value.

[0009] Furthermore, the thickness of the grating in the nano-metal grating is greater than or equal to 20 nm, the period is greater than or equal to 200 nm, and the duty cycle is 0.2 to 0.6.

[0010] Furthermore, the nano-metal grating is made of aluminum.

[0011] Furthermore, the antioxidant layer is made of a transparent material, and the thickness of the antioxidant layer is greater than or equal to 5 nm.

[0012] Furthermore, the antioxidant layer is made of silicon dioxide.

[0013] Furthermore, the metasurface is divided into transmissive metasurface and reflective metasurface.

[0014] Furthermore, the substrate of the transmissive metasurface is made of quartz glass, the dielectric layer of the transmissive metasurface is made of indium tin oxide, and the thickness of the dielectric layer is greater than or equal to 30 nm.

[0015] Furthermore, the substrate of the reflective metasurface is made of silicon or a highly reflective material, the dielectric layer of the reflective metasurface is made of aluminum, and the thickness of the dielectric layer is greater than or equal to 30 nm.

[0016] Secondly, the present invention provides a method for preparing the electro-reconfigurable metasurface described above, comprising the following steps:

[0017] (1) A dielectric layer is grown on a substrate using thin film deposition;

[0018] (2) A metal layer is grown on the dielectric layer using thin film deposition;

[0019] (3) Spin-coating photoresist onto the metal film and drying it;

[0020] (4) The pattern of the grating gap is exposed by electron beam and then developed;

[0021] (5) Metal gratings are fabricated using etching methods;

[0022] (6) A phase change material is grown using thin film deposition;

[0023] (7) Remove the photoresist on the grating using a stripping method;

[0024] (8) An antioxidant layer was grown using thin film deposition.

[0025] (9) Connect the voltage source to both ends of the dielectric layer to obtain an electro-reconfigurable metasurface. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an electro-reconfigurable metasurface provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the subwavelength unit structure in the electro-reconfigurable metasurface provided by the present invention;

[0028] Figure 3 The reflection spectrum is obtained from the reflective metasurface embodiment provided by this invention;

[0029] Figure 4 This is a chromaticity diagram obtained from an embodiment of the reflective metasurface provided by the present invention;

[0030] Figure 5 The transmission spectrum is obtained from the transmission metasurface embodiment provided by this invention;

[0031] Figure 6 This is a chromaticity diagram obtained from the transmissive metasurface embodiment provided by the present invention;

[0032] Figure 7 This is a flowchart of a method for preparing an electro-reconfigurable metasurface according to an embodiment of the present invention;

[0033] Figure 8 This is a process block diagram of a method for preparing an electro-reconfigurable metasurface according to an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] To achieve the function of modulating different structural colors with wavelengths within the visible spectrum and rapidly and reversibly modulating color grayscale, this invention provides an electro-reconfigurable metasurface, such as... Figure 1 As shown, the metasurface includes a voltage source 51 and a plurality of periodically arranged subwavelength units, with a minimum of four subwavelength units. Figure 2 As shown, the subwavelength unit includes a substrate 41, a dielectric layer 31, a nano-metal grating 21, a phase change material layer 22 filling the gaps between the nano-metal grating 21, and an anti-oxidation layer 11 arranged from bottom to top. The voltage source 51 is connected to both ends of the dielectric layer 31.

[0036] The principle of metasurface modulation of structural colors in the visible spectrum provided in this embodiment is as follows: Incident light with a certain frequency passes through the anti-oxidation layer 11 and reaches the metal grating 21 and the phase change material layer 22 filled between the grating gaps. Since the nano-metal grating is a subwavelength structure, this nano-grating structure, which is smaller than the wavelength of the incident light, has a confinement effect on surface plasmons. Therefore, after the incident light and the free electrons on the surface of the metal grating are coupled to each other, a local surface plasmon resonance phenomenon is generated, which enhances the local electric field and produces a strong absorption peak at the resonance wavelength, thus generating structural colors. According to the principle of local surface plasmon resonance, the enhanced local electric field and the strong absorption peak at the resonance wavelength are sensitive to the structural parameters near the nano-metal grating. Therefore, the position of the resonance wavelength and the size of the absorption peak can be modulated by adjusting the structural parameters of the metal grating 21 and the phase change material layer 22 filled between the grating gaps, as well as the thickness of the anti-oxidation layer 11, thereby modulating different structural colors.

[0037] Furthermore, in this embodiment, the phase transition of the phase change material layer 22 modulates the grayscale of the color. This embodiment uses phase change material to fill the gaps in the metal grating. The significant difference in photoelectric properties of the phase change material before and after the phase transition causes a change in the grayscale of the resulting structural color. Since the phase change material can undergo a reversible phase transition by generating Joule heating through an electric current, it provides electro-reconfigurable characteristics for the metasurface structure. The phase transition process of the phase change material layer 22 provided in this embodiment is as follows: When a wide and moderately strong electric pulse is applied to both ends of the dielectric layer 31 using a voltage source, the generated Joule heating causes the temperature of the phase change material layer 22 to be higher than the crystallization temperature but lower than the melting point, and the phase change material layer 22 transforms from an amorphous state to a crystalline state; when a short and strong electric pulse is applied to both ends of the dielectric layer 31 using a voltage source, the generated Joule heating causes the temperature of the phase change material layer 22 to be higher than the melting temperature. After rapid annealing, the phase change material layer 22 transforms from a crystalline state to an amorphous state.

[0038] Specifically, the nano-metal grating 21 provided in this embodiment can be made of metal materials such as gold, silver, and aluminum. Different structural parameters correspond to different structural colors. The structural parameters of the metal grating 21 that determine the structural color include the thickness h2 of the grating, the period p, and the duty cycle d. The duty cycle d is the ratio of the width w1 of the grating within one period p to the period p. After selecting the duty cycle d and the period p, the width w1 of the metal grating 21 should be less than the wavelength of the incident light, thereby forming a subwavelength structure.

[0039] The phase change material layer 22 provided in this embodiment is made of sulfur-based phase change materials or vanadium oxide materials, such as germanium tellurium, antimony tellurium, germanium-antimony-tellurium, or germanium-antimony-selenium tellurium. To ensure that the phase change material layer 22 can effectively adjust the grayscale of the obtained structural color, the thickness h3 of the phase change material layer 22 should not be less than 10 nm. Furthermore, due to the extinction coefficient of the material itself, to avoid excessive light attenuation in the material and resulting in low grayscale of the obtained structural color, the thickness h3 of the phase change material layer 22 should not be greater than 50 nm.

[0040] The anti-oxidation layer 11 can be made of silicon dioxide or other transparent materials, and its thickness h1 is not less than 5nm. It is used to prevent the metal grating 21 and the phase change material layer 22 from oxidation and to improve the service life of the metasurface.

[0041] The electro-reconfigurable metasurface provided in this embodiment has the following effects: (1) By adjusting the structural parameters of the metal grating and the phase change material layer filling the gap between the gratings, as well as the thickness of the anti-oxidation layer, the position of the resonant wavelength and the size of the absorption peak can be modulated, thereby achieving stable adjustment of the structural color; (2) By using phase change material to fill the gap between the metal gratings, the significant difference in photoelectric properties of the phase change material before and after the phase transition causes the grayscale of the resulting structural color to change, thereby achieving dynamic and reversible adjustment of the grayscale of the color; (3) The structural color generated by the local surface plasmon resonance in this embodiment is a physical color generated by a physical phenomenon, which is different from the chemical color generated by dyes. It is stable in nature, and the anti-oxidation layer on top of the metal grating and the phase change material provides anti-oxidation protection for the structure, further stabilizing the properties of the structural color. The structural color generated by this electro-reconfigurable metasurface has the advantages of non-volatility, anti-oxidation, low crosstalk, and low power consumption, and the grayscale of the structural color can be adjusted quickly and reversibly, which has great application value.

[0042] In one embodiment, to obtain structural colors within the visible spectrum, the thickness h2 of the metal grating 21 is not less than 20 nm, the period p is not less than 200 nm, and the duty cycle is 0.2 to 0.6.

[0043] In one embodiment, the substrate 41 of the metasurface may be made of silicon or silicon dioxide. If an electro-reconfigurable reflective metasurface is designed (see Embodiment 1 below), the substrate may be made of silicon or a highly reflective material; if an electro-reconfigurable transmissive metasurface is designed (see Embodiment 2 below), the substrate may be made of transparent materials such as quartz glass, i.e., silicon dioxide or silicon nitride.

[0044] In one embodiment, the dielectric layer 31 of the metasurface can be made of a transparent conductive material or a metallic material, and the thickness h4 of the dielectric layer 31 is not less than 30 nm. If an electro-reconfigurable reflective metasurface is designed (see Embodiment 1 below), the dielectric layer 31 can be made of a metallic material such as aluminum; if an electro-reconfigurable transmissive metasurface is designed (see Embodiment 2 below), the dielectric layer 31 is made of a transparent conductive material such as indium tin oxide.

[0045] The following detailed description of an electro-reconfigurable metasurface provided by the present invention, with reference to specific embodiments, is as follows:

[0046] Two embodiments of the present invention are described herein: an electro-reconfigurable reflective metasurface and an electro-reconfigurable transmissive metasurface.

[0047] Example 1:

[0048] This embodiment provides an electro-reconfigurable reflective metasurface design with CMY color system structural colors (subtractive primary colors). Different structural parameters are used to achieve the CMY structural colors, and grayscale modulation can be achieved through phase transitions of phase change materials. The design method is as follows:

[0049] The electro-reconfigurable reflective metasurface provided in this embodiment uses silicon as the substrate; aluminum as the dielectric layer; aluminum as the metal grating; Ge2Sb2Se4Te1 (GSST2241) as the phase change material; and silicon dioxide as the anti-oxidation layer. For visible light incident light, to ensure the electro-reconfigurable reflective metasurface generates localized surface plasmon resonances and obtains high-purity structural colors, the selected three-color unit parameters are as follows:

[0050] (1) For the cyan unit, the thickness of the dielectric layer is 40nm, the thickness of the metal grating is 30nm, the period of the metal grating is 500nm, the duty cycle of the metal grating is 0.4, the thickness of the phase change material is 20nm, and the thickness of the anti-oxidation layer is 20nm.

[0051] (2) For the magenta unit, the thickness of the dielectric layer is 40 nm, the thickness of the metal grating is 30 nm, the period of the metal grating is 400 nm, the duty cycle of the metal grating is 0.4, the thickness of the phase change material is 18 nm, and the thickness of the antioxidant layer is 20 nm.

[0052] (3) For the yellow unit, the thickness of the dielectric layer is 40nm, the thickness of the metal grating is 20nm, the period of the metal grating is 350nm, the duty cycle of the metal grating is 0.4, the thickness of the phase change material is 10nm, and the thickness of the anti-oxidation layer is 20nm.

[0053] Based on the above structure and parameters, verification of its reflectance spectrum shows that: Figure 3 and 4 As shown in the figure, a350, a400, and a500 are the reflectance spectra of the yellow, magenta, and cyan units (with periods of 350nm, 400nm, and 500nm respectively) in the visible light range and their positions in the chromaticity diagram when the phase change material is in an amorphous state, respectively; c350, c400, and c500 are the reflectance spectra of the yellow, magenta, and cyan units (with periods of 350nm, 400nm, and 500nm respectively) in the visible light range and their positions in the chromaticity diagram when the phase change material is in a crystalline state, respectively.

[0054] For the yellow unit, when the phase change material is amorphous, the device reflects yellow light with a reflectivity trough of 0.091 at 429 nm; when the phase change material is crystalline, the device reflects white light with a reflectivity of 0.394 for 429 nm wavelength light.

[0055] For the magenta unit, when the phase change material is amorphous, the device reflects magenta with a reflectivity trough of 0.026 at 534nm; when the phase change material is crystalline, the device reflects white with a reflectivity of 0.420 for 534nm wavelength light.

[0056] For the cyan unit, when the phase change material is amorphous, the device reflects cyan with a reflectivity trough of 0.030 at 602nm; when the phase change material is crystalline, the device reflects white with a reflectivity of 0.4383 for 602nm wavelength light.

[0057] The verification results of the reflection spectrum show that the design method of the electro-reconfigurable reflective metasurface provided in this embodiment is reliable and can obtain structural colors of the CMY color system with significant grayscale adjustment effect.

[0058] Example 2:

[0059] This embodiment provides an electro-reconfigurable transmissive metasurface design with RGB color system structural colors (additive color mixing of the three primary colors). Different structural parameters are used to achieve the RGB structural colors, and grayscale modulation can be achieved through phase transitions of phase change materials. The design method is as follows:

[0060] The electro-reconfigurable transmissive metasurface provided in this embodiment uses quartz glass, i.e., silicon dioxide, as its substrate; indium tin oxide as its dielectric layer; aluminum as its metal grating; Ge2Sb2Se4Te1 (GSST2241) as its phase change material; and silicon dioxide as its anti-oxidation layer. For visible light incident light, to ensure the electro-reconfigurable transmissive metasurface generates localized surface plasmon resonances and obtains high-purity structural colors, the selected three-color unit parameters are as follows:

[0061] (1) For the red unit, the thickness of the dielectric layer is 100nm, the thickness of the metal grating is 40nm, the period of the metal grating is 600nm, the duty cycle of the metal grating is 0.4, the thickness of the phase change material is 40nm, and the thickness of the anti-oxidation layer is 100nm.

[0062] (2) For the green unit, the thickness of the dielectric layer is 100nm, the thickness of the metal grating is 30nm, the period of the metal grating is 500nm, the duty cycle of the metal grating is 0.4, the thickness of the phase change material is 30nm, and the thickness of the antioxidant layer is 100nm.

[0063] (3) For the blue unit, the thickness of the dielectric layer is 60nm, the thickness of the metal grating is 20nm, the period of the metal grating is 310nm, the duty cycle of the metal grating is 0.4, the thickness of the phase change material is 20nm, and the thickness of the anti-oxidation layer is 10nm.

[0064] Based on the above structure and parameters, verification of its transmission spectrum shows that: Figure 5 and 6 As shown in the figure, a310, a500, and a600 are the transmission spectra of the blue, green, and red units (with periods of 310 nm, 500 nm, and 600 nm for the metal grating structure, respectively) in the visible light range and their positions in the chromaticity diagram when the phase change material is in an amorphous state, respectively; c310, c500, and c600 are the transmission spectra of the blue, green, and red units (with periods of 310 nm, 500 nm, and 600 nm for the metal grating structure, respectively) in the visible light range and their positions in the chromaticity diagram when the phase change material is in a crystalline state, respectively.

[0065] For the red unit, when the phase change material is amorphous, the device transmits red light with a peak transmittance of 0.502 at a position of 651 nm; when the phase change material is crystalline, the device transmittance is extremely low with a peak transmittance of only 0.070.

[0066] For the green unit, when the phase change material is amorphous, the device transmits green light with a peak transmittance of 0.422 nm at a peak position of 552 nm; when the phase change material is crystalline, the device transmittance is extremely low with a peak transmittance of only 0.089 nm.

[0067] For the blue unit, when the phase change material is amorphous, the device transmits blue light with a peak transmittance of 0.306 nm at a peak position of 495 nm; when the phase change material is crystalline, the device transmittance is extremely low with a peak transmittance of only 0.089 nm.

[0068] The verification results of the transmission spectrum show that the design method of the electro-reconfigurable transmission metasurface provided in this embodiment is reliable and can obtain structural colors of the RGB color system with significant grayscale adjustment effect.

[0069] The present invention describes one or more preferred embodiments. Any partial changes or modifications that are derived from the technical concept of the present invention and can be easily deduced by those skilled in the art do not depart from the scope of the patent rights of the present invention.

[0070] In addition, the present invention also provides a method for preparing the above-mentioned electro-reconfigurable metasurface, such as... Figure 7 As shown, it includes the following steps:

[0071] Step 1: A dielectric layer is grown on the substrate using thin film deposition.

[0072] Step 2: Using thin film deposition, a metal layer is grown on the dielectric layer.

[0073] Step 3: Spin coat the metal film obtained in step 2 with photoresist and dry it.

[0074] Step four: Expose the pattern of the grating gaps using an electron beam (EBL) and then develop the image.

[0075] Step 5: Use etching to fabricate the metal grating.

[0076] Step 6: Using thin film deposition, a phase change material layer is grown on the metal grating.

[0077] Step 7: Remove the photoresist on the grating using a stripping method.

[0078] Step 8: Use thin film deposition to grow an antioxidant layer.

[0079] Step nine: Connect the voltage source to both ends of the dielectric layer to obtain an electro-reconfigurable metasurface.

[0080] Specifically, the thin film deposition method provided in this embodiment can employ magnetron sputtering, such as... Figure 8 As shown.

[0081] The electro-reconfigurable metasurface prepared in the above steps can be used as a pixel unit. Different pixel units will be obtained by preparing it with different structural parameters. For example, if it is prepared with the three parameters in Example 1, three reflective CMY color pixel units of cyan, magenta and yellow can be obtained. If it is prepared with the three parameters in Example 2, three transmissive RGB color pixel units of red, green and blue can be obtained.

[0082] The method for fabricating metasurfaces provided by this invention has a simple manufacturing process, which gives this invention good application value.

[0083] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An electro-reconfigurable metasurface for the stable adjustment of structural colors in the visible spectrum and the dynamic and reversible adjustment of color grayscale, characterized in that, It includes a voltage source and a number of periodically arranged subwavelength units, the number of which is at least 4. Each subwavelength unit includes, from bottom to top, a substrate, a dielectric layer, a nano-metal grating, a phase change material layer filling the gaps between the nano-metal gratings, and an anti-oxidation layer. The voltage source is connected to both ends of the dielectric layer. The structural color within the visible spectrum is achieved by modulating the position of the resonant wavelength and the size of the absorption peak within the visible spectrum. The position of the resonant wavelength and the size of the absorption peak are achieved by adjusting the structural parameters of the nano-metal grating and the phase change material layer, as well as the thickness of the anti-oxidation layer. The structural parameters of the nano-metal grating include the grating thickness, period, and duty cycle. The duty cycle is the ratio of the grating width to the period within one period, and the width is less than the wavelength of the external incident light. The phase change material layer is made of chalcogenide phase change material or vanadium oxide material, including both amorphous and crystalline phases. The thickness of the phase change material layer is greater than 10 nm and less than or equal to 50 nm. The phase transition of the phase change material layer is achieved by adjusting the pulse width and voltage amplitude generated by the voltage source. The phase transition of the phase change material layer is used to achieve grayscale modulation of the color.

2. The electro-reconfigurable metasurface according to claim 1, characterized in that, The thickness of the nano-metal grating is greater than or equal to 20 nm, the period is greater than or equal to 200 nm, and the duty cycle is 0.2 to 0.

6.

3. The electro-reconfigurable metasurface according to claim 2, characterized in that, The nano-metal grating is made of aluminum.

4. The electro-reconfigurable metasurface according to claim 1, characterized in that, The antioxidant layer is made of a transparent material and has a thickness greater than or equal to 5 nm.

5. The electro-reconfigurable metasurface according to claim 4, characterized in that, The antioxidant layer is made of silicon dioxide.

6. The electro-reconfigurable metasurface according to claim 1, characterized in that, The metasurfaces are classified into transmissive metasurfaces and reflective metasurfaces.

7. The electro-reconfigurable metasurface according to claim 6, characterized in that, The substrate of the transmissive metasurface is made of quartz glass, and the dielectric layer of the transmissive metasurface is made of indium tin oxide material, with a thickness greater than or equal to 30 nm.

8. The electro-reconfigurable metasurface according to claim 6, characterized in that, The substrate of the reflective metasurface is made of silicon or a highly reflective material, and the dielectric layer of the reflective metasurface is made of aluminum, with a thickness greater than or equal to 30 nm.

9. A method for preparing an electro-reconfigurable metasurface according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) A dielectric layer is grown on a substrate using thin film deposition; (2) A metal layer is grown on the dielectric layer using thin film deposition; (3) Spin-coating photoresist onto the metal film and drying it; (4) The pattern of the grating gap is exposed by electron beam and then developed; (5) Metal gratings are fabricated using etching methods; (6) A phase change material is grown using thin film deposition; (7) Remove the photoresist on the grating using a stripping method; (8) An antioxidant layer was grown using thin film deposition. (9) Connect the voltage source to both ends of the dielectric layer to obtain an electro-reconfigurable metasurface.

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