Preparation method of novel gradient metasurface

Abstract

The invention relates to the technical field of plasmon nano photonics, and discloses a preparation method of a novel gradient metasurface, which comprises the following steps: pretreating an aluminum sheet; prefabricating a pattern on the aluminum sheet and performing anodic oxidation; the preparation method comprises the following steps: preparing an anodized aluminum oxide thin film, fixing the anodized aluminum oxide thin film on a glass sheet, placing the glass sheet fixed with the anodized aluminum oxide thin film in chambering liquid, and taking out the glass sheet to obtain the novel gradient metasurface. By adopting electrochemical and chemical corrosion methods, for gradient metasurfaces with different areas, different sizes and different directions, the diversity of adjustable parameters of the nano array can be enriched, the time is shortened, the cost is reduced, the manufacturing cost and time are reduced to a great extent, and the production efficiency is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of plasmon nanophotonics, and in particular to a method for preparing a novel gradient supersurface. Background Art

[0002] Plasmon is a collective oscillation phenomenon formed when a metal surface interacts with light, especially at the nanoscale. This phenomenon has triggered the rise of plasmon nanophotonics, which combines the properties of plasmons with the application of photonics and opens up a new research field. The uniqueness of plasmon nanophotonics lies in its ability to manipulate the propagation of light and enhance the interaction between light and matter at the nanoscale, which makes it have broad application prospects in biosensing, optical imaging, information processing, and energy conversion. Plasmon nanophotonics combines the physical properties of plasmons with the basic theory of nanophotonics. It controls the behavior of plasmons at the nanoscale to achieve light manipulation. Its basic principles mainly include the following aspects: 1. Excitation of plasmons The excitation of plasmons requires specific conditions, usually involving the electronic structure of the metal and the wavelength and angle of the incident light. At the interface between the metal and the medium, when the wave vector of the incident light matches the wave vector of the plasmon, resonance occurs, thereby exciting the plasmon.

[0003] 2. Plasmon propagation Plasmons can propagate on metal surfaces, and the electric field strength will gradually decay during the propagation process, but a strong local field can still be maintained at the nanoscale. This characteristic makes plasmons have a wide range of application potentials in nanophotonics.

[0004] 3. Plasmon Coupling Plasmons can couple with light in different ways to form hybrid states, which makes the application of plasmons in optical devices more flexible.

[0005] As an interdisciplinary subject, plasmon nanophotonics combines multiple fields such as optics, materials science and nanotechnology, providing us with rich research and application prospects. With the in-depth understanding of plasmon properties and the continuous development of new materials and technologies, plasmon nanophotonics will play an increasingly important role in biomedicine, environmental monitoring, energy conversion and other fields. In the future, with the advancement of technology and the increase in application demand, plasmon nanophotonics is expected to achieve breakthroughs in more fields.

[0006] Gradient metasurface is a metasurface structure with spatial modulation, which can precisely control light by adjusting the geometry and optical properties of materials at the nanoscale. Compared with traditional metasurfaces, gradient metasurfaces can achieve smooth changes in phase, amplitude, polarization and other aspects, thus showing unique functions and advantages in optical devices and systems: 1. Precisely control the phase and amplitude of light Gradient metasurfaces can adjust the phase and amplitude of light with nanometer-scale precision, thus achieving a high degree of control over light. This precise control gives it great flexibility and diversity in optical applications.

[0007] 2. Spatial Modulation By realizing spatial modulation on metasurfaces, complex light fields and optical effects such as vortex beams and specific polarization states can be generated. This spatial modulation capability provides more possibilities for the design of new optical devices.

[0008] 3. Thin design The structure of gradient metasurfaces is usually thin, which enables lightweight and miniaturized design in optical devices. This thin design makes gradient metasurfaces have wide application potential in mobile devices, wearable devices and other fields.

[0009] 4. Large-scale manufacturing With the development of nanofabrication technology, the fabrication of gradient metasurfaces has become increasingly feasible, and they can achieve highly consistent performance over large areas. This advantage makes gradient metasurfaces suitable for large-scale applications.

[0010] 5. Material Diversity Gradient metasurfaces can be designed using a variety of materials, including metals, dielectric materials, and two-dimensional materials. The diversity of materials enables gradient metasurfaces to achieve good optical performance in different bands and environmental conditions.

[0011] Gradient metasurface is an optical material with broad application prospects. By precisely controlling the propagation characteristics of light, it can play an important role in imaging, adaptive optics, stealth technology, photonic integrated circuits and other fields. Its unique advantages, such as precise phase and amplitude control, spatial modulation capability, thin design, large-area manufacturing and material diversity, make it show great potential in modern optics and nanotechnology. With the continuous deepening of related research, the application field of gradient metasurface will be further expanded, and it may play a more important role in future optical technology. Summary of the invention

[0012] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a new method for preparing a gradient super surface.

[0013] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing a novel gradient supersurface comprises the following steps: Step 1: Pre-treat the aluminum sheet. Cut the high-purity aluminum foil into round aluminum sheets with a diameter of 2 cm. Put the aluminum sheets into containers containing ethanol, water, and ethanol in turn. Wash them in an ultrasonic machine for 7 minutes respectively. Take out the aluminum sheet and blow dry it. Then, electrochemically polish the dried aluminum sheet. Put the polished aluminum sheet into an electrolyte in an ice water bath and pass a current of 30 V and 2 A. After 6-7 minutes, turn off the power, take out the aluminum sheet and rinse it. Step 2: Pre-pattern the aluminum sheet and perform anodization, cover the aluminum sheet obtained in step 1 with a square 400nm nickel film with periodic protrusions, use a hydraulic press to apply a pressure of 6 MPa for 2 min to form a square 400nm depression on the aluminum sheet, then place the aluminum sheet in electrolyte 2 at 4°C, pass a current of 160 V and 0.03 A, and oxidize for 1 h to obtain a circular porous anodized aluminum film; Step 3: Fix the anodized aluminum film obtained in step 2 on a glass sheet, place the glass sheet with the anodized aluminum film fixed in a pore expansion liquid, and take it out to obtain the novel gradient metasurface.

[0014] Preferably, in step 3, the anodized aluminum film obtained in step 2 is fixed on a glass sheet, the glass sheet is connected to one end of a peristaltic pump, and then the pull-back distance parameter and flow rate parameter of the peristaltic pump are set to set the time of chemical etching, the glass sheet fixed with the anodized aluminum film is placed vertically in a 40°C pore-widening solution, and then the peristaltic pump is started to pull the glass sheet back from the pore-widening solution at a uniform speed to obtain the novel gradient metasurface.

[0015] Preferably, in step 3, the anodized aluminum film obtained in step 2 is fixed on a glass sheet, and the glass sheet with the anodized aluminum film fixed thereon is placed in pore expansion solutions of different temperatures at different inclination angles, and different reaction times are set according to the temperature, so as to obtain a new type of gradient metasurface with different gradient areas and different pore size change ranges.

[0016] Preferably, the pore-enlarging liquid is a phosphoric acid solution with a mass fraction of 5%.

[0017] Preferably, in step 1, electrolyte 1 comprises perchloric acid and ethanol in a volume ratio of 1:7.

[0018] Preferably, in step 2, the second electrolyte comprises phosphoric acid, ethylene glycol and water in a volume ratio of 1:200:400.

[0019] The beneficial effects of the present invention are: 1. Reduce costs and production cycles: Compared with the existing mainstream gradient metasurface preparation methods (such as photolithography technology), this method uses electrochemical and chemical etching methods to achieve gradient metasurfaces for different regions, sizes, and directions. It can enrich the diversity of adjustable parameters of nanoarrays, while shortening time and reducing costs, greatly reducing production costs and time, and significantly improving production efficiency.

[0020] 2. High parameter flexibility: This method allows the parameters of the gradient metasurface to be flexibly adjusted according to different needs without investing a lot of additional funds and time, and has a high degree of customization capability.

[0021] 3. Meet the growing market demand: As various industries have shown great interest in the excellent properties exhibited by gradient metasurfaces, this method can better meet the increasing demand for gradient metasurface nanoarrays.

[0022] 4. Broad application prospects: The samples prepared by this method and their derived structures have broad application prospects in many fields, including but not limited to high-tech fields such as nonlinear optics, integrated chips, nanolasers and biosensors, and have significant technical advantages and industrial potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The basic preparation steps for porous anodized aluminum; Figure 2 It is the basic morphology of tetragonal 400 nm porous anodic aluminum oxide; Figure 3 This is a schematic diagram of an experimental device according to an embodiment of the present invention; Figure 4 Schematic diagram of a gradient supersurface with a gradient direction of Γ-X; Figure 5 This is a schematic diagram of an experimental device for Example 2 of the present invention; Figure 6 Schematic diagram of the gradient hypersurface with a gradient direction of Γ-M. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0025] Embodiment 1: like Figure 1First, pre-treat the aluminum sheet. Cut the high-purity aluminum foil into round aluminum sheets with a diameter of 2 cm, and put the aluminum sheets into small beakers containing anhydrous ethanol, ultrapure water, and anhydrous ethanol in turn. Wash them in an ultrasonic machine for 7 minutes to remove dust and oil on the surface of the aluminum sheet, and then take them out and blow dry. Subsequently, the aluminum sheet is electrochemically polished. Put the aluminum sheet into electrolyte 1 (electrolyte 1 includes 100 ml perchloric acid and 700 ml ethanol) in an ice water bath, connect the positive electrode to the aluminum sheet and the negative electrode to the lead plate, and pass a current of 30 V and 2 A. After 6-7 minutes, turn off the power, take out the aluminum sheet, and rinse it with anhydrous ethanol and ultrapure water in turn.

[0026] Pre-pattern on aluminum sheet and perform anodization. Cover the polished aluminum sheet with a nickel film with periodic protrusions of 400 nm in a square shape, and use a hydraulic press to apply a pressure of 6 MPa for 2 min to form a square 400 nm depression on the polished sheet. Place the aluminum sheet in electrolyte II at 4°C (in electrolyte II, phosphoric acid: ethylene glycol: water = 1:200:400), pass a current of 160V, 0.03 A, and oxidize for 1 h to obtain a porous anodized aluminum film with circular holes with a period of 400 nm in a square arrangement.

[0027] like Figure 3 Set the peristaltic pump parameters to a flow rate of 6.4 ml and a flow rate of 800 μL / m. Fix the obtained square 400 nm anodized aluminum film on a glass sheet with tape to ensure the flatness of the sample. Use tape or rope to connect the glass sheet with the sample to one end of the peristaltic pump.

[0028] The sample was placed vertically in a 50°C pore-enlarging liquid (the pore-enlarging liquid was a 5% by mass phosphoric acid solution), and the Γ-X azimuth of the sample was parallel to the surface of the pore-enlarging liquid. Then the peristaltic pump was started to pull the sample back from the pore-enlarging liquid at a uniform speed. When the sample was pulled back, the contact reaction time with the pore-enlarging liquid gradually decreased, thereby obtaining the following Figure 4 A gradient metasurface with a gradient area of ​​1 cm and a gradient direction of Γ-X.

[0029] Embodiment 2: like Figure 1First, pre-treat the aluminum sheet. Cut the high-purity aluminum foil into round aluminum sheets with a diameter of 2 cm, and put the aluminum sheets into small beakers containing anhydrous ethanol, ultrapure water, and anhydrous ethanol in turn. Wash them in an ultrasonic machine for 7 minutes to remove dust and oil on the surface of the aluminum sheet, and then take them out and blow dry. Subsequently, the aluminum sheet is electrochemically polished. Put the aluminum sheet into electrolyte 1 (electrolyte 1 includes 100 ml perchloric acid and 700 ml ethanol) in an ice water bath, connect the positive electrode to the aluminum sheet and the negative electrode to the lead plate, and pass a current of 30 V and 2 A. After 6-7 minutes, turn off the power, take out the aluminum sheet, and rinse it with anhydrous ethanol and ultrapure water in turn.

[0030] Pre-pattern the aluminum sheet and perform anodization. Cover the polished aluminum sheet with a nickel film with periodic protrusions of 400 nm in a square shape, and use a hydraulic press to apply a pressure of 6 MPa for 2 min to form a square 400 nm depression on the polished sheet. Place the aluminum sheet in electrolyte II at 4 °C (in electrolyte II, phosphoric acid: ethylene glycol: water = 1:200:400), pass a current of 160V, 0.03 A, and oxidize for 1 h to obtain a porous anodized aluminum film with circular holes with a period of 400 nm in a square arrangement.

[0031] like Figure 5 The obtained anodized aluminum film was fixed on a glass sheet, and the glass sheet with the sample fixed was vertically placed in a pore expansion liquid (a 5% phosphoric acid solution) at a temperature of 30°C and immersed for 5 hours, and the azimuth angle of the sample Γ-M was parallel to the liquid surface, so as to obtain the following Figure 6 The gradient metasurface has a gradient area of ​​50 μm and a gradient direction of Γ-M.

[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a novel gradient super surface, characterized in that: The following steps are involved: Step 1: Pre-treat the aluminum sheet, cut the high-purity aluminum foil into round aluminum sheets, and put the aluminum sheets into containers containing ethanol, water, and ethanol in turn, wash them in an ultrasonic machine, take out the aluminum sheet and blow dry it, then electrochemically polish the dried aluminum sheet, put the polished aluminum sheet into an electrolyte in an ice water bath, and pass a current of 30 V, 2 A. After 6-7 minutes, turn off the power, take out the aluminum sheet and rinse it; Step 2: Pre-pattern the aluminum sheet and perform anodization, cover the aluminum sheet obtained in step 1 with a square nickel film with periodic protrusions, apply a pressure of 6 MPa using a hydraulic press to form square depressions on the aluminum sheet, and then place the aluminum sheet in electrolyte 2 at 4°C, pass a current of 160 V and 0.03 A, and oxidize for 1 h to obtain a circular porous anodized aluminum film; Step 3: Fix the anodized aluminum film obtained in step 2 on a glass sheet, place the glass sheet with the anodized aluminum film fixed in a pore expansion liquid, and take it out to obtain the novel gradient metasurface.

2. The method for preparing a novel gradient supersurface according to claim 1, characterized in that: In step 3, the anodized aluminum film obtained in step 2 is fixed on a glass sheet, the glass sheet is connected to one end of a peristaltic pump, and then the pull-back distance parameter and flow rate parameter of the peristaltic pump are set to set the time of chemical etching, the glass sheet fixed with the anodized aluminum film is placed vertically in a 40°C pore-widening solution, and then the peristaltic pump is started to pull the glass sheet back from the pore-widening solution at a uniform speed to obtain the novel gradient metasurface.

3. The method for preparing a novel gradient supersurface according to claim 1, characterized in that: In step 3, the anodized aluminum film obtained in step 2 is fixed on a glass sheet, and the glass sheet with the anodized aluminum film fixed is placed in pore expansion liquids of different temperatures at different inclination angles, and different reaction times are set according to the temperature, so as to obtain a new type of gradient metasurface with different gradient areas and different pore size change ranges.

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