Terahertz metasurface with graphene and gold film double-layer structure and preparation and application of terahertz metasurface

Abstract

The invention discloses a terahertz metasurface with a graphene and gold film double-layer structure and preparation and application of the terahertz metasurface. The terahertz metasurface with the graphene and gold thin film double-layer structure comprises a lower gold thin film layer, a substrate layer and a periodic structure unit layer which are sequentially arranged from bottom to top, the periodic structure unit layer comprises a plurality of periodic structure units, each periodic structure unit presents two I-shaped structures which are crossed, and each periodic structure unit comprises an upper gold film layer arranged on the upper surface of the substrate layer and a graphene layer arranged on the upper surface of the upper gold film layer; and the lower metal film layer is fully paved on the lower surface of the substrate layer and can be connected with an external wire to receive a radio frequency signal.

Description

Technical Field

[0001] The invention belongs to the field of micro-nano manufacturing technology, and in particular relates to a terahertz super surface with a double-layer structure of graphene and gold film, and preparation and application thereof. Background Art

[0002] Currently, the demand for high data rate transmission and ultra-high resolution imaging for wireless communications is growing rapidly, pushing the carrier frequency of wireless communication systems to higher spectral regions such as terahertz (THz). The terahertz band is a part of the electromagnetic spectrum that lies between microwaves and infrared, with a frequency range of approximately 300 GHz to 3 THz. In the terahertz region, ultra-high bandwidth enables high-speed communication at data rates of up to terabits per second, making it an ideal choice for next-generation wireless networks.

[0003] In recent years, electronic devices in the terahertz band have been widely studied and applied, mainly in the fields of communication, imaging, sensing and optics in the terahertz band. However, due to frequency multiplication, mixing and network amplification, electronic devices in the terahertz band have high stray noise and mutual interference problems. The development of terahertz wireless communication technology has been hindered by the lack of materials and devices that can exceed the current frequency limit.

[0004] Metasurfaces composed of subwavelength, periodic arrays exhibit physical properties that natural materials cannot achieve. These structures can control the amplitude, polarization, and phase of terahertz waves. Based on the unique electrical properties of graphene metamaterials (high charge carrier mobility, electric field tunable conductivity, etc.), they have been applied in the field of terahertz devices, such as modulators, absorbers, filters, lasers, etc. These applications have led to a large number of theoretical studies on the design of graphene for terahertz metasurface devices.

[0005] Graphene micro-nano image processing technology can produce graphene devices and nanostructures with complex structures and high resolution, which are widely used in nanoelectronics, sensors, photonics, biomedicine, nanorobotics and other fields. These processed devices and structures can realize multiple functions, such as photoelectric sensors, electronic devices, nanocircuits, nanotransmission lines, etc., providing important tools and platforms for the development of micro-nano technology. Summary of the invention

[0006] The present invention is made in order to increase the selection space of terahertz metasurfaces and provide a terahertz metasurface with good processability and stable performance.

[0007] As a first aspect of the present invention, it relates to a graphene and gold film double-layer structure terahertz super surface, comprising a lower gold film layer, a substrate layer and a periodic structure unit layer arranged in sequence from bottom to top;

[0008] The periodic structure unit layer includes a plurality of periodic structure units, wherein each of the periodic structure units presents two I-shaped structures that cross each other, and the structure periodic unit includes an upper gold film layer disposed on the upper surface of the substrate layer and a graphene layer disposed on the upper surface of the upper gold film layer;

[0009] The lower metal film layer covers the lower surface of the substrate layer and can be connected to an external wire to receive a radio frequency signal.

[0010] In some feasible specific implementations, the multiple periodic structure units of the periodic structure unit layer are arranged in an array on the upper surface of the substrate layer and are parallel to each other.

[0011] In certain feasible specific embodiments, the ratio of the side length of the circumscribed rectangle of the periodic structural unit to the side length of the substrate layer is 1 to 15:300;

[0012] And the interval distance between every two adjacent periodic structural units is equal to the side length of the circumscribed rectangle of the periodic structural unit.

[0013] In some feasible specific implementations, the substrate layer is in a square shape with a side length of 1 cm to 3 cm; and the side length of the circumscribed rectangle of the periodic structural unit is 200 μm to 500 μm.

[0014] In some feasible specific implementations, the thickness ratio of the lower gold thin film layer, the graphene layer, and the upper gold thin film layer is 1-5:1-5:1-5.

[0015] In some feasible specific embodiments, the thickness of the lower gold thin film layer is 100nm to 500nm, the thickness of the upper gold thin film layer is 100nm to 500nm, and the thickness of the graphene layer is 100nm-500nm.

[0016] In some feasible embodiments, the thickness of the substrate layer is 100 μm to 500 μm.

[0017] In some feasible specific implementations, the substrate layer is a Rogers 5880 substrate, a silicon dioxide substrate or a polyimide substrate.

[0018] In certain feasible specific implementations, in the two I-shaped structures of the cross of the periodic structural unit, the width of each side of each I-shaped structure is 1 / 10 of the side length of the circumscribed rectangle of the periodic structural unit;

[0019] In the two I-shaped structures of the cross of the periodic structural unit, the length of the top side and the bottom side of each of the I-shaped structures is 1 / 2 of the side length of the circumscribed rectangle of the periodic structural unit.

[0020] In certain feasible specific implementations, the two I-shaped structures of the cross of the periodic structural unit have the same size, and the intersection of the two I-shaped structures is the center of the I-shaped structure.

[0021] As a second aspect of the present invention, it relates to a method for preparing a terahertz super surface with a double-layer structure of graphene and gold film, comprising the following steps:

[0022] (1) depositing gold on the lower surface of the substrate layer by magnetron sputtering to form a lower gold thin film layer;

[0023] (2) depositing gold on the upper surface of the substrate layer using a hard mask to form an upper gold thin film layer of a plurality of periodic structural units;

[0024] (3) growing a silicon dioxide film on a silicon substrate as a substrate for graphene growth;

[0025] (4) depositing a graphene film on the upper surface of the substrate by a chemical vapor deposition method;

[0026] (5) spin coating a PMMA material on the upper surface of the graphene film, immersing the substrate on which the PMMA is spin coated in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0027] (6) Using glass to transfer the floating graphene film into clean water and clean it, so that the graphene film floats on the surface of the clean water;

[0028] (7) placing the substrate layer, removing the clean water, and allowing the cleaned graphene film to fall exactly on the upper surface of the substrate layer, covering the upper gold film layer, and forming a graphene layer of multiple periodic structural units;

[0029] (8) immersing the substrate layer after the graphene film is transferred in an acetone solution to remove the PMMA material;

[0030] (9) Cleaning the graphene film outside the region where the multiple periodic structural units are located with deionized water, and drying to obtain the graphene and gold film double-layer structure terahertz supersurface.

[0031] In certain feasible specific implementations, in the process of depositing gold on the upper surface of the substrate layer using a hard mask to form a gold thin film layer of a plurality of periodic structural units:

[0032] First, a silicon substrate is arranged on the upper surface of the substrate layer, and a hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0033] Next, a layer of photoresist is spin-coated on the hard mask;

[0034] Next, the pattern on the mask is transferred to the photoresist through exposure and development;

[0035] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to expose the area on the upper surface of the substrate layer where gold needs to be deposited;

[0036] Next, gold is deposited on the exposed areas using electrochemical deposition.

[0037] In certain feasible embodiments, during the process of depositing a graphene film on the upper surface of the substrate by a chemical vapor deposition method:

[0038] First, the cleaned substrate is placed in a CVD reaction chamber;

[0039] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0040] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0041] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, which were maintained for 5 minutes, and then methane gas with a flow rate of 1.5 sccm was introduced for 10 minutes to allow the chemical substances to be deposited on the substrate surface to form graphene;

[0042] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0043] In certain feasible embodiments, the method further comprises:

[0044] Gold contacts are selected on the lower gold film layer and silver epoxy is used to make electrical connections with external wires.

[0045] As a third aspect of the present invention, it relates to a modulator using the above-mentioned graphene and gold film double-layer structure terahertz supersurface.

[0046] As a fourth aspect of the present invention, it relates to a filter using the above-mentioned graphene and gold film double-layer structure terahertz supersurface.

[0047] As a fifth aspect of the present invention, it relates to a terahertz imaging device, which uses the above-mentioned graphene and gold film double-layer structure terahertz supersurface.

[0048] As a sixth aspect of the present invention, it relates to a wireless terahertz communication device, which uses the above-mentioned graphene and gold film double-layer structure terahertz supersurface.

[0049] As a seventh aspect of the present invention, it relates to a terahertz sensor, characterized in that it uses the above-mentioned graphene and gold film double-layer structure terahertz supersurface.

[0050] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0051] The terahertz metasurface of a double-layer structure of graphene and gold film provided in an embodiment of the present invention has a structural periodic unit including an upper gold film layer arranged on the upper surface of the substrate layer and a graphene layer arranged on the upper surface of the upper gold film layer, forming a "sandwich structure" of graphene, gold film and substrate, combining the double-layer design of graphene and gold film, providing stable support through the substrate layer structure, and having good conductivity and reflection in the terahertz band through the upper metal film layer, thereby ensuring smooth transmission of current and facilitating the processing and enhancement of terahertz wave signals. The conductivity of the graphene layer can be adjusted according to external conditions (such as electric field and magnetic field), thereby realizing dynamic regulation of terahertz waves. Compared with the terahertz metasurface of pure gold film or the terahertz metasurface of pure graphene structure or graphene patch provided in the prior art, the adjustability of the terahertz metasurface is improved, and better performance is shown in the terahertz band, including higher reflectivity and a wider frequency response range. By adjusting parameters such as the thickness of the graphene layer and the thickness of the gold film layer, tunability can be achieved and the performance of the terahertz metasurface can be further optimized to meet different application requirements.

[0052] The graphene and gold film double-layer structure terahertz supersurface provided in the embodiment of the present invention has a periodic structural unit using two I-shaped structures crossed in a "cross" shape, which is convenient for structural molding and has good processability, thereby improving the success rate of manufacturing the terahertz supersurface. In addition, the influence of the micro-nano effect is taken into consideration, thereby improving the performance stability of the terahertz supersurface.

[0053] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of the structure of a terahertz supersurface with a double-layer structure of graphene and gold film provided in an embodiment of the present invention.

[0055] Figure 2 It is a schematic diagram of the specific structure of the periodic structural unit of the graphene and gold film double-layer structure terahertz supersurface provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0057] The inventors have found that since graphene films are difficult to process and integrate micro-nano images into functional devices without significantly affecting their electrical properties, the research on these functional devices is still in its infancy. The existing graphene terahertz supersurfaces and their preparation processes still have problems such as unsatisfactory performance and difficult preparation, and in-depth scientific research is still needed. Based on this, an embodiment of the present invention provides a graphene and gold film double-layer structure terahertz supersurface and its preparation and application.

[0058] Embodiment 1

[0059] Reference Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a graphene and gold film double-layer structure terahertz super surface, including a lower gold film layer, a substrate layer and a periodic structure unit layer arranged in sequence from bottom to top;

[0060] The periodic structure unit layer includes a plurality of periodic structure units, wherein each of the periodic structure units presents two I-shaped structures that cross each other, and the structure periodic unit includes an upper gold film layer disposed on the upper surface of the substrate layer and a graphene layer disposed on the upper surface of the upper gold film layer;

[0061] The lower metal film layer covers the lower surface of the substrate layer and can be connected to an external wire to receive a radio frequency signal.

[0062] The terahertz metasurface of a double-layer structure of graphene and gold film provided in an embodiment of the present invention has a structural periodic unit including an upper gold film layer arranged on the upper surface of the substrate layer and a graphene layer arranged on the upper surface of the upper gold film layer, forming a "sandwich structure" of graphene, gold film and substrate, combining the double-layer design of graphene and gold film, providing stable support through the substrate layer structure, and having good conductivity and reflection in the terahertz band through the upper metal film layer, thereby ensuring smooth transmission of current and facilitating the processing and enhancement of terahertz wave signals. The conductivity of the graphene layer can be adjusted according to external conditions (such as electric field and magnetic field), thereby realizing dynamic regulation of terahertz waves. Compared with the terahertz metasurface of pure gold film or the terahertz metasurface of pure graphene structure or graphene patch provided in the prior art, the adjustability of the terahertz metasurface is improved, and better performance is shown in the terahertz band, including higher reflectivity and a wider frequency response range. By adjusting parameters such as the thickness of the graphene layer and the thickness of the gold film layer, tunability can be achieved and the performance of the terahertz metasurface can be further optimized to meet different application requirements.

[0063] The graphene and gold film double-layer structure terahertz supersurface provided in the embodiment of the present invention has a periodic structural unit using two I-shaped structures crossed in a "cross" shape, which is convenient for structural molding and has good processability, thereby improving the success rate of manufacturing the terahertz supersurface. In addition, the influence of the micro-nano effect is taken into consideration, thereby improving the performance stability of the terahertz supersurface.

[0064] In an alternative embodiment, referring to Figure 2 As shown, the multiple periodic structural units of the periodic structural unit layer are arranged in an array on the upper surface of the substrate layer and are parallel to each other. The array arrangement of multiple periodic structural units enables the terahertz metasurface to realize complex functions in a limited space, which is conducive to the miniaturization and integration of devices. By accurately designing the size, shape and arrangement of the periodic structural units, precise control of terahertz waves can be achieved. The arrayed periodic structural units can cooperate with each other to jointly enhance the performance of the terahertz metasurface. In addition, it is easy to process and manufacture.

[0065] In a specific embodiment, the substrate layer is in the shape of a square with a side length of 1 cm to 3 cm; the side length of the circumscribed rectangle of the periodic structure unit is 200 μm to 500 μm, and the spacing distance between every two adjacent periodic structure units is equal to the side length of the circumscribed rectangle of the periodic structure unit. By reasonably selecting the size of the substrate layer, it is possible to accommodate enough periodic structure units. The square shape also helps to maintain the symmetry and uniformity of the structure and improve the overall performance of the metasurface. The size and spacing distance of the periodic structure units, and the smaller unit size help to improve the resolution and sensitivity of the metasurface, which can not only optimize the tuning performance of the terahertz metasurface, but also enable the terahertz metasurface to have the highest possible broadband tuning. At the same time, the periodicity and orderliness of the metasurface structure are ensured, which helps to form a uniform electromagnetic field distribution and stable scattering characteristics.

[0066] In a specific embodiment, the thickness of the lower gold film layer is 100nm to 500nm, the thickness of the substrate layer is 100μm to 500μm, the thickness of the upper gold film layer is 100nm to 500nm, and the thickness of the graphene layer is 100nm-500nm. By reasonably setting the thickness of each layer of the terahertz supersurface with a double-layer structure of graphene and gold film, it is ensured that the gold film has good conductivity and reflectivity, while maintaining reasonable cost and material usage. Thinner films may be difficult to form a complete continuous layer, affecting the conductive properties; while thicker films may increase costs and unnecessary material waste. The thickness range of the substrate layer provides sufficient mechanical strength and stability to support the multilayer structure above. As a conductive layer, the upper gold film layer is thick enough to ensure good current transmission and signal quality. The thickness of the stacked graphene layer is 100nm to 500nm. By adjusting the thickness, electromagnetic regulation can be achieved to optimize the tuning performance of the terahertz supersurface.

[0067] In a specific embodiment, the substrate layer is a Rogers 5880 substrate, a silicon dioxide substrate or a polyimide substrate. The above three materials have a lower dielectric constant and loss tangent, which helps to reduce the attenuation and distortion of the signal during transmission. In addition, they also have good thermal stability and mechanical strength.

[0068] In a specific embodiment, in the two I-shaped structures of the cross of the periodic structural unit, the width of each side of each I-shaped structure is 1 / 10 of the side length of the circumscribed rectangle of the periodic structural unit;

[0069] In the two I-shaped structures of the cross of the periodic structural unit, the length of the top side and the bottom side of each of the I-shaped structures is 1 / 2 of the side length of the circumscribed rectangle of the periodic structural unit.

[0070] Specifically, the two I-shaped structures of the cross of the periodic structure unit have the same size, and the intersection of the two I-shaped structures is the center of the I-shaped structure.

[0071] In the embodiment of the present invention, by setting the width and length of the side of the I-shaped structure, the structural stability of the I-shaped structure is ensured, which helps to increase the fineness of the structure and the sensitivity of electromagnetic control. By using two I-shaped structures that cross in a "cross" shape, the two I-shaped structures are symmetrical, not only have high anisotropy, but also the terahertz metasurface exhibits more uniform electromagnetic properties as a whole. This I-shaped structure is more convenient to process, so as to further ensure the overall performance and consistency of the terahertz metasurface.

[0072] In order to more clearly illustrate the graphene and gold thin film double-layer structure terahertz supersurface provided by the embodiment of the present invention, the following example of a method for preparing the graphene and gold thin film double-layer structure terahertz supersurface is provided.

[0073] Before preparing the graphene and gold film double-layer structure terahertz super surface, the pattern to be etched can be designed and optimized by electromagnetic simulation software to achieve better tuning performance and as high broadband tuning as possible for the terahertz super surface. The electromagnetic simulation software can be selected from the ANSYS series software. In the embodiment of the present invention, the Maxwell module in ANSYS Electronics Desktop is used to implement the simulation process. First, a geometric model is created: two I-shaped structures with a "cross" cross are used as periodic structural units to design the geometric figures of the terahertz super surface, and the CAD file (Auto CAD drawing) of the designed geometric figures is imported to create a geometric model describing the microstructure of the terahertz emission source to reflect the physical size and shape of the emission source. Next, define the material properties: assign material properties to different parts of the model in the material library of ANSYS, including the materials of the substrate layer, the lower gold film layer, the upper gold film layer and the graphene layer. Next, set the grid: use the grid division tool of ANSYS to grid the geometric model. The density and shape of the grid can be adjusted according to the requirements of simulation accuracy and computing resources. Next, set up the simulation: Select the analysis type: Select frequency domain analysis as the simulation target. Set boundary conditions: Set appropriate boundary conditions for the model, set gold as a perfect conductor, and set graphene as a perfect emitter. Set the excitation source: According to the working principle of the terahertz emission source, set the bottom surface as a voltage source. The parameters of the voltage source are the actual voltage (6V) of future physical tests to ensure the accuracy of the simulation results. Set the solution parameters: Set the parameters of the solver according to the simulation requirements, such as the number of iterations, convergence criteria, and solution accuracy. Finally, run the simulation and analyze the results: Use ANSYS's post-processing tools to view and analyze the simulation results. Select the size and shape of the optimized pattern to be etched.

[0074] Exemplarily, in the embodiment of the present invention, the size and shape parameters of the pattern to be etched after optimization are selected as shown in Table 1. The corresponding hard masks are made of silicon dioxide according to the different pattern sizes and shapes. Based on this, in the embodiment of the present invention, the selected graphene and gold film double-layer structure terahertz super surface is as shown in Examples 1-5, wherein the size of the periodic structural unit of each graphene and gold film double-layer structure terahertz super surface, the size of the substrate layer, the thickness of the substrate layer, the lower gold film layer, the upper gold film layer and the graphene layer are shown in Table 1.

[0075] Table 1 Parameters of graphene and gold film double-layer structure terahertz metasurface

[0076]

[0077] Example 1

[0078] Step 1, deposit gold on the lower surface of the substrate layer:

[0079] Gold was deposited on the lower surface of the substrate layer of 1 cm*1 cm*100 μm by magnetron sputtering to form a gold film with a thickness of 100 nm;

[0080] Step 2: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0081] First, a silicon substrate is placed on the upper surface of the substrate layer, and a 1 cm*1 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0082] Next, a layer of photoresist is spin-coated on the hard mask;

[0083] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0084] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0085] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 100 nm.

[0086] Step 3: Prepare the substrate for graphene growth:

[0087] A layer of silicon dioxide film is grown on a 1cm*1cm silicon substrate as a substrate for graphene growth;

[0088] Step 4, forming a graphene film by chemical vapor deposition on the surface of the substrate:

[0089] First, the cleaned substrate is placed in a CVD reaction chamber;

[0090] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0091] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0092] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, which were maintained for 5 minutes, and then a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the substrate surface to form a 100 nm thick graphene film;

[0093] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0094] Step 5, transferring the graphene film to the upper surface of the substrate layer:

[0095] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0096] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0097] Next, the substrate layer is placed, and the clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, covers the upper gold film layer, and forms a graphene layer of multiple periodic structural units;

[0098] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0099] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain the graphene and gold film double-layer structure terahertz supersurface.

[0100] Wherein, in the above step 2, an acetone solution may be used to remove the photoresist, and a phosphoric acid solution with a concentration of not less than 85% may be used to remove the hard mask.

[0101] In the above step 5, the transfer solution is prepared by mixing water and isopropanol in a ratio of 95 ml:5 ml.

[0102] In the embodiment of the present invention, after the above preparation method obtains the graphene and gold film double-layer structure terahertz supersurface, gold contacts can be selected on the lower gold film layer and electrically connected to external wires using silver epoxy resin.

[0103] Example 2

[0104] Step 1, deposit gold on the lower surface of the substrate layer:

[0105] Gold was deposited on the lower surface of the substrate layer of 2.5 cm*2.5 cm*200 μm by magnetron sputtering to form a gold film with a thickness of 200 nm;

[0106] Step 2: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0107] First, a silicon substrate is placed on the upper surface of the substrate layer, and a 2.5 cm*2.5 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0108] Next, a layer of photoresist is spin-coated on the hard mask;

[0109] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0110] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0111] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 200 nm.

[0112] Step 3: Prepare the substrate for graphene growth:

[0113] A layer of silicon dioxide film is grown on a 2.5cm*2.5cm silicon substrate as a substrate for graphene growth;

[0114] Step 4, forming a graphene film by chemical vapor deposition on the surface of the substrate:

[0115] First, the cleaned substrate is placed in a CVD reaction chamber;

[0116] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0117] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0118] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, and the flow rate was maintained for 5 minutes. Then, a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the surface of the substrate to form a graphene film with a thickness of 200 nm.

[0119] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0120] Step 5, transferring the graphene film to the upper surface of the substrate layer:

[0121] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0122] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0123] Next, the substrate layer is placed, and the clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, covers the upper gold film layer, and forms a graphene layer of multiple periodic structural units;

[0124] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0125] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain the graphene and gold film double-layer structure terahertz supersurface.

[0126] Wherein, in the above step 2, an acetone solution may be used to remove the photoresist, and a phosphoric acid solution with a concentration of not less than 85% may be used to remove the hard mask.

[0127] In the above step 5, the transfer solution is prepared by mixing water and isopropanol in a ratio of 95 ml:5 ml.

[0128] In the embodiment of the present invention, after the above preparation method obtains the graphene and gold film double-layer structure terahertz supersurface, gold contacts can be selected on the lower gold film layer and electrically connected to external wires using silver epoxy resin.

[0129] Example 3

[0130] Step 1, deposit gold on the lower surface of the substrate layer:

[0131] Gold was deposited on the lower surface of the substrate layer of 3 cm*3 cm*500 μm by magnetron sputtering to form a gold film with a thickness of 500 nm;

[0132] Step 2: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0133] First, a silicon substrate is placed on the upper surface of the substrate layer, and a 3 cm*3 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0134] Next, a layer of photoresist is spin-coated on the hard mask;

[0135] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0136] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0137] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 500 nm.

[0138] Step 3: Prepare the substrate for graphene growth:

[0139] A layer of silicon dioxide film is grown on a 3cm*3cm silicon substrate as a substrate for graphene growth;

[0140] Step 4, forming a graphene film by depositing it on the surface of the substrate by chemical vapor deposition method:

[0141] First, the cleaned substrate is placed in a CVD reaction chamber;

[0142] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0143] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0144] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, and the flow rates were maintained for 5 minutes. Then, a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the substrate surface to form a graphene film with a thickness of 500 nm.

[0145] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0146] Step 5, transferring the graphene film to the upper surface of the substrate layer:

[0147] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0148] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0149] Next, the substrate layer is placed, and the clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, covers the upper gold film layer, and forms a graphene layer of multiple periodic structural units;

[0150] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0151] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain the graphene and gold film double-layer structure terahertz supersurface.

[0152] Wherein, in the above step 2, an acetone solution may be used to remove the photoresist, and a phosphoric acid solution with a concentration of not less than 85% may be used to remove the hard mask.

[0153] In the above step 5, the transfer solution is prepared by mixing water and isopropanol in a ratio of 95 ml:5 ml.

[0154] In the embodiment of the present invention, after the above preparation method obtains the graphene and gold film double-layer structure terahertz supersurface, gold contacts can be selected on the lower gold film layer and electrically connected to external wires using silver epoxy resin.

[0155] Example 4

[0156] Step 1, deposit gold on the lower surface of the substrate layer:

[0157] Gold was deposited on the lower surface of the substrate layer of 2.5 cm*2.5 cm*200 μm by magnetron sputtering to form a gold film with a thickness of 200 nm;

[0158] Step 2: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0159] First, a silicon substrate is placed on the upper surface of the substrate layer, and a 2.5 cm*2.5 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0160] Next, a layer of photoresist is spin-coated on the hard mask;

[0161] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0162] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0163] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 200 nm.

[0164] Step 3: Prepare the substrate for graphene growth:

[0165] A layer of silicon dioxide film is grown on a 2.5cm*2.5cm silicon substrate as a substrate for graphene growth;

[0166] Step 4, forming a graphene film by chemical vapor deposition on the surface of the substrate:

[0167] First, the cleaned substrate is placed in a CVD reaction chamber;

[0168] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0169] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0170] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, and the flow rate was maintained for 5 minutes. Then, a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the surface of the substrate to form a graphene film with a thickness of 200 nm.

[0171] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0172] Step 5, transferring the graphene film to the upper surface of the substrate layer:

[0173] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0174] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0175] Next, the substrate layer is placed, and the clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, covers the upper gold film layer, and forms a graphene layer of multiple periodic structural units;

[0176] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0177] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain the graphene and gold film double-layer structure terahertz supersurface.

[0178] Wherein, in the above step 2, an acetone solution may be used to remove the photoresist, and a phosphoric acid solution with a concentration of not less than 85% may be used to remove the hard mask.

[0179] In the above step 5, the transfer solution is prepared by mixing water and isopropanol in a ratio of 95 ml:5 ml.

[0180] In the embodiment of the present invention, after the above preparation method obtains the graphene and gold film double-layer structure terahertz supersurface, gold contacts can be selected on the lower gold film layer and electrically connected to external wires using silver epoxy resin.

[0181] Example 5

[0182] Step 1, deposit gold on the lower surface of the substrate layer:

[0183] Gold was deposited on the lower surface of the substrate layer of 2.5 cm*2.5 cm*200 μm by magnetron sputtering to form a gold film with a thickness of 200 nm;

[0184] Step 2: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0185] First, a silicon substrate is placed on the upper surface of the substrate layer, and a 2.5 cm*2.5 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0186] Next, a layer of photoresist is spin-coated on the hard mask;

[0187] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0188] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0189] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 200 nm.

[0190] Step 3: Prepare the substrate for graphene growth:

[0191] A layer of silicon dioxide film is grown on a 2.5cm*2.5cm silicon substrate as a substrate for graphene growth;

[0192] Step 4, forming a graphene film by chemical vapor deposition on the surface of the substrate:

[0193] First, the cleaned substrate is placed in a CVD reaction chamber;

[0194] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0195] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0196] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, and the flow rate was maintained for 5 minutes. Then, a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the surface of the substrate to form a graphene film with a thickness of 200 nm.

[0197] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0198] Step 5, transferring the graphene film to the upper surface of the substrate layer:

[0199] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0200] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0201] Next, the substrate layer is placed, and the clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, covers the upper gold film layer, and forms a graphene layer of multiple periodic structural units;

[0202] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0203] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain the graphene and gold film double-layer structure terahertz supersurface.

[0204] Wherein, in the above step 2, an acetone solution may be used to remove the photoresist, and a phosphoric acid solution with a concentration of not less than 85% may be used to remove the hard mask.

[0205] In the above step 5, the transfer solution is prepared by mixing water and isopropanol in a ratio of 95 ml:5 ml.

[0206] In the embodiment of the present invention, after the above preparation method obtains the graphene and gold film double-layer structure terahertz supersurface, gold contacts can be selected on the lower gold film layer and electrically connected to external wires using silver epoxy resin.

[0207] Comparative Example 1

[0208] Step 1: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0209] First, a silicon substrate is placed on the upper surface of a substrate layer of 1 cm*1 cm*100 μm, and a 1 cm*1 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0210] Next, a layer of photoresist is spin-coated on the hard mask;

[0211] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0212] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0213] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 100 nm.

[0214] Step 2: Prepare the substrate for graphene growth:

[0215] A layer of silicon dioxide film is grown on a 1cm*1cm silicon substrate as a substrate for graphene growth;

[0216] Step 3, forming a graphene film by depositing it on the surface of the substrate by chemical vapor deposition method:

[0217] First, the cleaned substrate is placed in a CVD reaction chamber;

[0218] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0219] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0220] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, which were maintained for 5 minutes, and then a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the substrate surface to form a 100 nm thick graphene film;

[0221] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0222] Step 4, transferring the graphene film to the upper surface of the substrate layer:

[0223] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0224] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0225] Next, the substrate layer is placed, and the clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, covers the upper gold film layer, and forms a graphene layer of multiple periodic structural units;

[0226] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0227] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain a terahertz super surface.

[0228] Comparative Example 2

[0229] Gold was deposited on the lower surface of the substrate layer of 1 cm*1 cm*100 μm by magnetron sputtering to form a gold film with a thickness of 100 nm;

[0230] Step 2: Deposit gold on the upper surface of the substrate layer using a hard mask:

[0231] First, a silicon substrate is placed on the upper surface of the substrate layer, and a 1 cm*1 cm hard mask pre-made with silicon dioxide is positioned and fixed on the upper surface of the silicon substrate;

[0232] Next, a layer of photoresist is spin-coated on the hard mask;

[0233] Next, the pattern on the hard mask is transferred to the photoresist through exposure and development;

[0234] Next, using reactive ion etching (RIE) technology, etching is performed in an alternative gas (such as argon) to remove the photoresist and hard mask by a chemical dissolution method, thereby exposing the area on the upper surface of the substrate layer where gold needs to be deposited;

[0235] Next, gold was deposited on the exposed area using an electrochemical deposition method to form a gold film with a thickness of 100 nm, thereby obtaining a pure gold film structure terahertz supersurface.

[0236] Comparative Example 3

[0237] Step 1, deposit gold on the lower surface of the substrate layer:

[0238] Gold was deposited on the lower surface of the substrate layer of 1 cm*1 cm*100 μm by magnetron sputtering to form a gold film with a thickness of 100 nm;

[0239] Step 2: Prepare the substrate for graphene growth:

[0240] A layer of silicon dioxide film is grown on a 1cm*1cm silicon substrate as a substrate for graphene growth;

[0241] Step 3, forming a graphene film by depositing it on the surface of the substrate by chemical vapor deposition method:

[0242] First, the cleaned substrate is placed in a CVD reaction chamber;

[0243] Next, introduce argon gas into the CVD reaction chamber and exhaust it at a high flow rate for 20 minutes to ensure that all the air in the tube is exhausted;

[0244] Next, after the exhaust is completed, a mixed gas of 500 sccm of argon and 500 sccm of hydrogen is introduced, the temperature is raised to 1050°C for 60 minutes, and the temperature is kept constant for annealing for 30 minutes;

[0245] Next, the hydrogen gas was adjusted to 0.5 sccm and the argon gas to 950 sccm, which were maintained for 5 minutes, and then a methane gas with a flow rate of 1.5 sccm was introduced to grow graphene, so that the chemical substances were deposited on the substrate surface to form a 100 nm thick graphene film;

[0246] Finally, after the growth is completed, the methane gas is turned off and the temperature is lowered to room temperature to complete the preparation of the graphene film.

[0247] Step 4, transferring the graphene film to the upper surface of the substrate layer:

[0248] First, a PMMA material is spin-coated on the upper surface of the graphene film, and the substrate on which the PMMA is spin-coated is immersed in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution;

[0249] Next, the floating graphene film is transferred to clean water with glass and cleaned, so that the graphene film floats on the surface of the clean water;

[0250] Next, a substrate layer is placed, and clean water is pumped away, so that the cleaned graphene film falls exactly on the upper surface of the substrate layer, forming a graphene layer with multiple periodic structural units;

[0251] Next, the substrate layer after the graphene film is transferred is immersed in an acetone solution to remove PMMA;

[0252] Next, the graphene film outside the region where the multiple periodic structural units are located is cleaned with deionized water, and dried to obtain a terahertz super surface.

[0253] Experimental verification:

[0254] The terahertz wave absorption performance of the terahertz metasurface obtained in the above examples 1-5 and comparative examples 1-3 was measured using a terahertz time-domain spectrometer (model: separated terahertz time-domain spectrometer TA-TDS-SEP). The specific experimental process includes:

[0255] Prepare a power supply and a bias voltage device for providing a stable bias voltage.

[0256] The sample was connected to a power supply and bias voltage device, and a bias voltage of 6V was applied.

[0257] Terahertz time-domain spectroscopy (THz-TDS) was used to measure the terahertz wave absorption properties of the samples before and after applying a bias voltage.

[0258] During the measurement process, the experimental environment must be kept stable to avoid the influence of external factors on the measurement results.

[0259] The measured data were recorded, including key indicators such as frequency response, absorption rate, tuning amplitude, etc. The measured data were processed and analyzed, and the tuning performance and broadband tuning capability of the sample were calculated to obtain the experimental results, as shown in Table 2.

[0260] Experimental results show that the graphene and gold film double-layer structure terahertz metasurface prepared in the embodiment of the present invention exhibits excellent tuning performance under a bias voltage of 6V compared with the terahertz metasurfaces of comparative examples 1-3, while maintaining high-quality resonance and having high-bandwidth tuning capability.

[0261] Table 2 Experimental results

[0262]

[0263] Embodiment 2

[0264] Based on the same inventive concept, an embodiment of the present invention further provides a modulator using the graphene and gold film double-layer structure terahertz supersurface prepared in the above-mentioned embodiment 1.

[0265] Embodiment 3

[0266] Based on the same inventive concept, an embodiment of the present invention further provides a filter, using the graphene and gold film double-layer structure terahertz supersurface prepared in the above embodiment one.

[0267] Embodiment 4

[0268] Based on the same inventive concept, an embodiment of the present invention further provides a terahertz imaging device, which uses the graphene and gold film double-layer structure terahertz supersurface prepared in the above embodiment one.

[0269] Embodiment 5

[0270] Based on the same inventive concept, an embodiment of the present invention further provides a wireless terahertz communication device, which uses the graphene and gold film double-layer structure terahertz supersurface prepared in the above embodiment one.

[0271] Embodiment 6

[0272] Based on the same inventive concept, an embodiment of the present invention further provides a terahertz sensor, which uses the graphene and gold film double-layer structure terahertz supersurface prepared in the above embodiment 1.

[0273] Unless otherwise stated, any technical solution disclosed in the present invention disclosed above, if it discloses a numerical range, then the disclosed numerical range is a preferred numerical range, and any technician in the field should understand that the preferred numerical range is only a numerical value with a more obvious technical effect or representative value among many implementable numerical values. Since there are too many numerical values ​​to be exhaustive, the present invention discloses some numerical values ​​to illustrate the technical solution of the present invention, and the numerical values ​​listed above should not constitute a limitation on the scope of protection of the present invention.

[0274] If the words "first", "second", etc. are used in this article to limit components, those skilled in the art should know that the use of "first" and "second" is only to distinguish the components for the convenience of description. Unless otherwise stated, the above words have no special meaning.

[0275] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the present invention include states or shapes that are approximate, similar, or close to them.

[0276] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A terahertz supersurface with a double-layer structure of graphene and gold film, characterized in that: It includes a lower gold film layer, a substrate layer and a periodic structure unit layer which are arranged in sequence from bottom to top; The periodic structure unit layer includes a plurality of periodic structure units, wherein each of the periodic structure units presents two I-shaped structures that cross each other, and the structure periodic unit includes an upper gold film layer disposed on the upper surface of the substrate layer and a graphene layer disposed on the upper surface of the upper gold film layer; The lower metal film layer covers the lower surface of the substrate layer and can be connected to an external wire to receive a radio frequency signal.

2. The graphene and gold film double-layer structure terahertz supersurface according to claim 1, characterized in that: The multiple periodic structure units of the periodic structure unit layer are arranged in an array on the upper surface of the substrate layer and are parallel to each other.

3. The graphene and gold film double-layer structure terahertz supersurface according to claim 2, characterized in that: The ratio of the side length of the circumscribed rectangle of the periodic structural unit to the side length of the substrate layer is 1 to 15:300; And the interval distance between every two adjacent periodic structural units is equal to the side length of the circumscribed rectangle of the periodic structural unit.

4. The graphene and gold film double-layer structure terahertz supersurface according to claim 1, characterized in that: The thickness ratio of the lower gold thin film layer, the graphene layer and the upper gold thin film layer is 1-5:1-5:1-5.

5. A method for preparing a terahertz supersurface with a double-layer structure of graphene and gold film, characterized in that: The following steps are involved: (1) depositing gold on the lower surface of the substrate layer by magnetron sputtering to form a lower gold thin film layer; (2) depositing gold on the upper surface of the substrate layer using a hard mask to form an upper gold thin film layer of a plurality of periodic structural units; (3) growing a silicon dioxide film on a silicon substrate as a substrate for graphene growth; (4) depositing a graphene film on the upper surface of the substrate by a chemical vapor deposition method; (5) spin coating a PMMA material on the upper surface of the graphene film, immersing the substrate on which the PMMA is spin coated in a transfer solution for etching, so that the graphene film is separated from the substrate and floats on the surface of the transfer solution; (6) Using glass to transfer the floating graphene film to clean water and wash it, so that the graphene film floats on the surface of the clean water; (7) placing the substrate layer, removing the clean water, and allowing the cleaned graphene film to fall exactly on the upper surface of the substrate layer, covering the upper gold film layer, and forming a graphene layer of multiple periodic structural units; (8) immersing the substrate layer after the graphene film is transferred in an acetone solution to remove the PMMA material; (9) Cleaning the graphene film outside the region where the multiple periodic structural units are located with deionized water, and drying to obtain the graphene and gold film double-layer structure terahertz supersurface.

6. A modulator, characterized in that: A terahertz super surface with a double-layer structure of graphene and gold film as described in any one of claims 1 to 4 is used.

7. A filter, characterized in that: A terahertz super surface with a double-layer structure of graphene and gold film as described in any one of claims 1 to 4 is used.

8. A terahertz imaging device, characterized in that: A terahertz super surface with a double-layer structure of graphene and gold film as described in any one of claims 1 to 4 is used.

9. A wireless terahertz communication device, characterized in that: A terahertz super surface with a double-layer structure of graphene and gold film as described in any one of claims 1 to 4 is used.

10. A terahertz sensor, characterized in that: A terahertz supersurface with a double-layer structure of graphene and gold film as described in any one of claims 1 to 4 is used.

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