Plasmonic metasurface and method for manufacturing the same
Plasma metasurfaces were prepared by seed-mediated and template assembly methods, solving the problems of high cost and high loss. This resulted in low-cost, high-efficiency preparation of plasma metasurfaces with high optical performance, suitable for multiple optical applications.
Patent Information
- Application Number
- CN202510555851.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2026-08-25
AI Technical Summary
Existing methods for preparing plasma metasurfaces suffer from high costs and high losses, making it difficult to achieve high precision and large-scale production. Furthermore, traditional methods struggle to address both radiation and non-radiation losses simultaneously.
Single-crystal plasma nanoparticles were synthesized using a seed-mediated method, and plasma metasurfaces were constructed using a template assembly method. Low-optical-loss plasma nanoparticles and functionalized ligand molecules were combined with nanoimprinting technology to rapidly assemble micro- and nanostructures.
This technology enables the low-cost and high-efficiency fabrication of plasma metasurfaces, reducing optical losses and improving electromagnetic wave modulation effects, making it suitable for multiple optical applications.
Smart Images
Figure CN122632366A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of two-dimensional metasurface technology, specifically relating to a plasma metasurface and its preparation method. Background Technology
[0002] Two-dimensional plasmonic metasurfaces are subwavelength-scale artificial materials that can be used to adjust parameters such as the phase, polarization state, intensity, wavelength, and bandwidth of electromagnetic waves. With continuous advancements in technology, metasurfaces have shown enormous application potential in numerous fields.
[0003] However, the fabrication of plasma metasurfaces currently faces many challenges: (1) Traditional top-down processing methods such as photolithography, although capable of large-area and low-cost fabrication, have limited resolution and cannot meet high-precision requirements; electron beam etching (EBL), while having high resolution, is costly and inefficient, making large-scale production impossible; nanoimprint technology has stringent material requirements and cannot fabricate high-melting-point metal microstructures. (2) During the modulation of electromagnetic waves, some energy is inevitably lost due to the interaction between the material and light. The electromagnetic loss of metasurfaces mainly comes from two aspects: radiation loss and non-radiation loss. Radiation loss mainly comes from the conversion of plasmons to photons, while non-radiation loss comes from interband excitation and electron scattering. These limitations restrict the modulation effect of metasurfaces on electromagnetic waves, becoming a bottleneck restricting their application in multiple optical applications.
[0004] In summary, given the existing shortcomings of two-dimensional metasurfaces, there is currently no effective means to simultaneously solve both problems. Summary of the Invention
[0005] The purpose of this invention is to provide a simple-to-operate, low-optical-loss plasma metasurface and its preparation method. First, single-crystal plasma nanoparticles are synthesized by a seed-mediated method. Then, the plasma nanoparticles are arranged into an array structure by a template assembly method to construct a plasma metasurface with single-crystal plasma nanoparticles as superatoms. By using the above key technologies, the preparation cost of the metasurface is reduced, the optical performance of the metasurface is improved, and the shortcomings of existing related technologies are overcome.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] This application discloses a low-optical-loss plasma metasurface, comprising superatoms and a substrate material. The superatoms are composed of low-optical-loss plasma nanoparticles, and the substrate material comprises all planar materials that can provide support. The plasma nanoparticles have a single-crystal structure and their surfaces are coated with functionalized ligand molecules.
[0008] Preferably, the plasma nanoparticles are composed of gold, silver, and aluminum.
[0009] Preferably, the plasma nanoparticles are spherical, rod-shaped, or helical in shape.
[0010] Preferably, the functionalized ligand molecules all contain thiol groups. The ligand molecules also contain at least one of the following properties: 1) hydrophilicity (e.g., polyethylene glycol, polyvinylpyrrolidone, bovine serum albumin); 2) charged properties (e.g., sodium polystyrene sulfonate, (11-mercaptodecyl)trimethylamine bromide).
[0011] This application also discloses a method for low-cost fabrication of plasma metasurfaces, which specifically includes the following steps:
[0012] S1. Prepare the assembly master template;
[0013] S2. Prepare a sub-template using the master template from step S1;
[0014] S3, Synthetic plasma nanoparticles;
[0015] S4. Using the sub-template from step S2, assemble the plasma nanoparticles from step S3 onto the substrate to obtain a plasma metasurface.
[0016] Preferably, step S1 specifically includes the following sub-steps:
[0017] S11. Spin-coat photoresist onto the substrate surface;
[0018] S12. Expose and develop the photoresist to obtain a master template with surface micro-patterns.
[0019] Preferably, the exposure method in step S12 includes ultraviolet exposure and electron beam exposure.
[0020] Preferably, step S2 specifically includes the following sub-steps:
[0021] S21. Cast the polydimethylsiloxane precursor onto the mother template in step S12;
[0022] S22. After cross-linking and curing, the material is demolded to obtain a sub-mold containing surface micro-patterns.
[0023] Preferably, the crosslinking curing temperature in step S22 is 80°C and the time is 5 hours.
[0024] Preferably, step S3 employs a seed-mediated method, which specifically includes the following sub-steps:
[0025] S31, The reducing agent reacts with the precursor to generate seeds;
[0026] S32. The reducing agent further reduces the precursor and grows it on the seed from step S31.
[0027] S33. Plasma nanoparticles were obtained by ligand modification.
[0028] Preferably, the reducing agent includes sodium borohydride, ascorbic acid, sodium citrate, etc.
[0029] Preferably, step S4 uses a template assembly method, which specifically includes the following sub-steps:
[0030] S41. Surface activation of the substrate;
[0031] S42. Drop the plasma nanoparticle suspension obtained in step S3 onto the substrate activated in step S41.
[0032] S43. Cover the sub-template from step S2, and remove the sub-template after the solvent has completely evaporated to obtain the plasma metasurface.
[0033] Preferably, the surface activation in step S41 includes two methods: 1) plasma treatment to change hydrophilicity and hydrophobicity; 2) spin-coating of polyelectrolyte solution to change charge.
[0034] Compared with the prior art, the present invention has the following advantages:
[0035] 1) This invention proposes a low-optical-loss plasma metasurface. The plasma nanoparticles synthesized using a seed-mediated method exhibit high uniformity and low defect density, effectively suppressing radiation loss. By using conductive noble metals (such as gold, silver, and aluminum) to support resonances with spectral energies lower than their interband transitions, non-radiative losses can be effectively reduced. This overcomes the shortcomings of existing preparation methods, which suffer from high optical losses, and provides better optical performance for the metasurface.
[0036] 2) This invention provides a low-cost, simple, and efficient method for fabricating plasma metasurfaces. Template assembly technology is a novel micro / nano fabrication technique derived from nanoimprinting. It induces nanomaterials to spontaneously assemble into the voids of the template, forming micro / nano structures. Compared to nanoimprinting, it retains the advantages of simple, efficient fabrication of micro / nano structures and high resolution, and overcomes the limitations of low melting point and high fluidity of printing materials through the self-assembly of nanomaterials. Compared to top-down fabrication methods such as electron beam etching and focused ion beam etching, it significantly reduces manufacturing costs through rapid replication and reuse of sub-templates, and the simple and efficient assembly method also greatly improves production efficiency. Attached Figure Description
[0037] Figure 1 This is a flowchart of the process for preparing the master template and the sub-template in this invention.
[0038] Figure 2This is a flowchart of the synthesis of plasma nanoparticles using the seed-mediated method in this invention.
[0039] Figure 3 This is a flowchart of the preparation of plasma metasurfaces using the template assembly method in this invention.
[0040] In the figure: 1-Electron beam, 2-Photoresist, 3-Substrate 1, 4-Sub-template, 5-Substrate 2, 6-Activated surface, 7-Solvent, 8-Plasma nanoparticles. Detailed Implementation
[0041] 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. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Any metasurface obtained by changing the nanoparticle material or shape but still assembling using the template method will infringe upon the patent of this invention.
[0042] This application discloses a low-optical-loss plasma metasurface, comprising superatoms and a substrate material. The superatoms are composed of low-optical-loss plasma nanoparticles, and the substrate material comprises all planar materials that can provide support. The plasma nanoparticles have a single-crystal structure and their surfaces are coated with functionalized ligand molecules.
[0043] This application also discloses a method for low-cost fabrication of plasma metasurfaces, which specifically includes the following steps:
[0044] S1. Prepare the assembly master template.
[0045] S2. Prepare a sub-template using the master template from step S1.
[0046] S3, Synthetic plasma nanoparticles.
[0047] S4. Using the sub-template from step S2, assemble the plasma nanoparticles from step S3 onto the substrate surface to obtain a plasma metasurface.
[0048] In one feasible embodiment, such as Figure 1 As shown, step S1 specifically includes the following sub-steps:
[0049] S11. Spin-coat photoresist onto the substrate surface;
[0050] S12. Expose and develop the photoresist to obtain a master template with surface micro-patterns.
[0051] In one feasible embodiment, the exposure method in step S12 includes ultraviolet exposure and electron beam exposure.
[0052] In one feasible embodiment, such as Figure 1 As shown, step S2 specifically includes the following sub-steps:
[0053] S21. Cast the polydimethylsiloxane precursor onto the mother template in step S12;
[0054] S22. After cross-linking and curing, the material is demolded to obtain a sub-mold containing surface micro-patterns.
[0055] In one feasible embodiment, the crosslinking curing temperature in step S22 is 80°C and the time is 5 hours.
[0056] In one feasible embodiment, step S3 specifically includes the following sub-steps:
[0057] S31, The reducing agent reacts with the precursor to generate seeds;
[0058] S32. The reducing agent further reduces the precursor and grows it on the seed from step S31.
[0059] S33. Plasma nanoparticles were obtained by ligand modification.
[0060] In one feasible embodiment, the reducing agent includes sodium borohydride, ascorbic acid, sodium citrate, etc.
[0061] In one feasible embodiment, such as Figure 3 As shown, step S4 uses the template assembly method, which specifically includes the following sub-steps:
[0062] S41. Surface activation of the substrate;
[0063] S42. Drop the plasma nanoparticle suspension obtained in step S3 onto the substrate activated in step S41.
[0064] S43. Cover the sub-template from step S2, and remove the sub-template after the solvent has completely evaporated to obtain the plasma metasurface.
[0065] In one feasible embodiment, surface activation in step S41 includes two methods: 1) plasma treatment to change hydrophilicity and hydrophobicity; 2) spin-coating of polyelectrolyte solution to change charge.
[0066] Example 1:
[0067] In this embodiment, the substrate 3 for preparing the sub-template is made of silicon, and the photoresist 2 on its surface is polymethyl methacrylate. The preparation process is as follows: Figure 1 As shown, photoresist 2 is first spin-coated onto substrate 3, and then the master template micro-pattern is prepared by electron beam exposure 1 and development. Polydimethylsiloxane precursor is cast onto the master template, crosslinked and cured at 80°C for 5 hours, and then peeled off to obtain sub-template 4.
[0068] In this embodiment, the plasma nanoparticle material is gold, spherical in shape, with a radius of 50 nm, and polyethylene glycol with thiol-terminated methyl groups as surface ligands. The preparation process is as follows: Figure 2 As shown, chloroauric acid (precursor) is first reduced to gold seeds with a diameter of 2-3 nm using sodium borohydride (reducing agent). Then, chloroauric acid (precursor) is further reduced using ascorbic acid (reducing agent) and deposited onto the gold seeds described in step S31, gradually growing into gold nanospheres with a diameter of 50 nm. Subsequently, the surface of the gold nanospheres described in step S32 is modified using thiol- and methyl-terminated polyethylene glycol (ligands) to obtain hydrophilic gold nanospheres.
[0069] In this embodiment, the substrate material for preparing the metasurface is quartz, and the surface is activated using oxygen plasma. The preparation process is as follows: Figure 3 As shown, the surface of substrate 25 was first treated with oxygen plasma, and then a suspension of gold nanoparticles (7, 8) was dropped onto the surface of substrate 25 and covered with a sub-template 4. After the solvent had completely evaporated, the sub-template was removed to obtain the plasma metasurface.
Claims
1. A plasma metasurface, composed of superatoms and a substrate material, characterized in that, The superatoms are composed of plasma nanoparticles synthesized by a seed-mediated method. The plasma nanoparticles have a single-crystal structure, which can effectively reduce optical loss. The plasma nanoparticles are bonded to the substrate surface through hydrophilic-hydrophobic interactions or electrostatic interactions.
2. The plasma metasurface as described in claim 1, characterized in that, The plasma nanoparticles are made of materials including gold, silver, and aluminum.
3. The plasma metasurface as described in claim 1, characterized in that, The plasma nanoparticles are rod-shaped, spherical, or helical.
4. A method for preparing a plasma metasurface, characterized in that, The plasmonic metasurface is prepared by arranging the superatoms into an array structure on a substrate using a template assembly method. Specific steps include: S1. Prepare the assembly master template; S2. Prepare a sub-template using the master template from step S1; S3, Synthetic plasma nanoparticles; S4. The plasma nanoparticles from step S3 are assembled onto the substrate using the sub-template from step S2 to obtain the plasma metasurface as described in claim 1.
5. The method for preparing a plasma metasurface as described in claim 4, characterized in that, Steps S1 and S2 specifically include the following sub-steps: S11. Spin-coat photoresist onto the substrate surface; S12. Expose and develop the photoresist to obtain a master template with surface micro-patterns; S21. Cast the polydimethylsiloxane precursor onto the mother template in step S12; S22. After cross-linking and curing, the material is demolded to obtain a sub-mold containing surface micro-patterns.
6. The method for preparing a plasma metasurface as described in claim 5, characterized in that, The exposure methods in step S12 include ultraviolet exposure and electron beam exposure.
7. The method for preparing a plasma metasurface as described in claim 4, characterized in that, Step S3 specifically includes the following sub-steps: S31, The reducing agent reacts with the precursor to generate seeds; S32. The reducing agent further reduces the precursor and grows it on the seed from step S31. S33. Plasma nanoparticles were obtained by ligand modification.
8. The method for preparing a plasma metasurface as described in claim 7, characterized in that, The standard deviation of the plasma nanoparticle size obtained in step S3 is less than 5 nm.
9. The method for preparing a plasma metasurface as described in claim 4, characterized in that, Step S4 specifically includes the following sub-steps: S41. Surface activation of the substrate; S42. Drop the suspension of plasma nanoparticles obtained in step S3 onto the surface of the substrate activated in step S41. S43. Cover the sub-template from step S2, and remove the sub-template after the solvent has completely evaporated to obtain the plasma metasurface.
10. The method for preparing a plasma metasurface as described in claim 9, wherein substrate surface activation includes: 1) Plasma treatment alters the surface's hydrophilicity and hydrophobicity; 2) Spin-coating polyelectrolytes with positive / negative charges alters the surface charge.