A metasurface lens nanocasting process

Abstract

The super surface lens nano casting process provided by the application comprises the following steps: a mold with a plurality of columnar protrusions in the same shape as the nano column is prepared; a first resin liquid is poured into the mold; a substrate is placed; a filling structure is formed after solidification; the filling structure has a plurality of deep holes; a second resin liquid is poured into the deep holes; and a nano column is formed after solidification. The filling structure with a plurality of deep holes is used as a mold for preparing the nano column, and the nano column does not need to be separated from the filling structure after solidification. The problems that the existing process is difficult to form a vertical, smooth and high-consistency nano structure are overcome. The problems that the existing process is complicated, the equipment cost is high, and the time consumption is long are also overcome. The super surface lens prepared by the super surface lens nano casting process has high yield and good consistency, can produce nano columns with consistent structures according to requirements, and the whole process is efficient, large-scale and low-cost, thereby promoting the industrial application of the super surface lens in various fields.

Description

Technical Field

[0001] This invention relates to the field of optical device manufacturing technology, and in particular to a nano-casting process for metasurface lenses. Background Technology

[0002] Metasurface lenses, as a novel type of planar optical element, precisely control the amplitude, phase, and polarization of light through subwavelength-scale artificial microstructures. They can achieve the functions of traditional optical lenses while possessing advantages such as ultrathinness, lightweight design, and ease of integration, demonstrating enormous application potential in fields such as micro-imaging, optoelectronic co-packaging, AR / VR displays, laser communication, bio-imaging, and high-end optical instruments. Their core performance depends on the geometric parameters (such as diameter, height, and spacing) and arrangement precision of the nanostructures, especially high aspect ratio structures—nanopillar arrays with a height-to-diameter ratio exceeding 10:1—which are key to achieving wide-band efficient control, high numerical aperture, and multifunctional integration.

[0003] DUV lithography and NIL lithography are the mainstream fabrication processes for metasurface lenses. In terms of process flow, both processes follow the core steps of substrate cleaning, functional layer deposition, photoresist coating, patterning, development or demolding, etching or stripping, and photoresist removal and cleaning. In the end, they both need to transfer the template pattern formed by photoresist to the functional layer through plasma dry etching to obtain the nanopillar structure of the metasurface lens.

[0004] Both DUV lithography and NIL lithography face similar drawbacks in the fabrication of metasurface lenses, which are the main bottlenecks for the large-scale application of metasurface lenses. First, neither process can perfectly achieve the high aspect ratio nanostructures required for metasurface lenses, easily leading to problems such as sidewall tilting, undercutting during etching, structural collapse, or adhesion, deviating from the ideal design and resulting in low mass production yields. Second, dimensional deviations are difficult to avoid; deviations in key parameters such as linewidth, height, and duty cycle can lead to decreased focusing efficiency, increased chromatic and aberration, and increased scattering loss, affecting optical performance. Finally, since both processes ultimately rely on dry etching, etching damage and surface roughness issues arise, leading to increased scattering and absorption, and decreased phase modulation accuracy. It is difficult to form vertical, smooth, and highly consistent nanostructures, and the overall process steps are cumbersome, with high equipment costs and long processing times, further limiting their low-cost, large-scale application.

[0005] The present invention aims to overcome the above-mentioned defects of the prior art and provide an improved nano-casting process for metasurface lenses to achieve high-quality, high-throughput, and mass production of metasurface lenses, thereby accelerating their industrial application in various fields. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a nano-casting process for metasurface lenses, overcoming the issues of high manufacturing costs, complex processes, and low product yield in existing technologies. This enables high-efficiency, high-yield, large-scale, and low-cost production of metasurface lenses, accelerating their industrial application in various fields.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The above technical solution has the following advantages or beneficial effects: A nano-casting process for a metasurface lens, the metasurface lens comprising a substrate, a plurality of nanopillars disposed on the substrate, and a filling structure filling the spaces between the nanopillars, wherein the process includes a preparation mold having a plurality of columnar protrusions having the same shape as the nanopillars. It also includes the following steps: S1: Pour the first resin liquid into the mold; S2: Place the substrate on the first resin liquid; S3: Solidify the first resin liquid in the mold; S4: The cured first resin liquid is removed from the mold to obtain a filled structure, which has a number of deep pores that fit the nanopillars. S5: With the side of the filling structure with the deep hole opening facing upwards, pour the second resin liquid into the deep hole; S6: Curing the second resin liquid to form the nanopillars after curing.

[0008] The above-mentioned metasurface lens nano-casting process further includes: S7: polishing and grinding the opening surface of the filling structure and the nanopillars.

[0009] The above-mentioned metasurface lens nanocasting process further includes: S7': applying an anti-reflective coating to the opening surface of the filling structure and the surface of the nanopillar.

[0010] The above-mentioned metasurface lens nano-casting process further includes step S6' after step S5: covering the upper surface of the second resin liquid with a glass cover plate, the upper surface of which is coated with an anti-reflective coating.

[0011] In the above-mentioned metasurface lens nano-casting process, the curing in step S3 adopts UV irradiation curing technology or thermal curing technology; the curing in step S6 adopts UV irradiation curing technology or thermal curing technology.

[0012] A nano-casting process for a metasurface lens, the metasurface lens comprising a substrate, a plurality of nanopillars disposed on the substrate, and a filling structure filling the spaces between the nanopillars, wherein the process includes a preparation mold and a transfer carrier plate, the mold having a plurality of columnar protrusions having the same shape as the nanopillars, and at least one side of the transfer carrier plate being a plane; It also includes the following steps: S1: Pour the first resin liquid into the mold; S2: Place a transfer carrier plate on the upper surface of the first resin liquid, with the plane of the transfer carrier plate facing the first resin liquid; S3: Solidify the first resin liquid in the mold, and at the same time complete the temporary bonding between the first resin liquid and the transfer carrier plate; S4: The cured first resin liquid is removed from the mold to obtain a filled structure, which has a number of deep pores that fit the nanopillars. S5: With the side of the filling structure with the deep hole opening facing upwards, pour the second resin liquid into the deep hole; S6: Place the substrate on the second resin liquid; S7: Solidify the second resin liquid to form the nanopillar.

[0013] S8: Debond the transfer carrier plate to obtain a flat lower surface of the filling structure.

[0014] The above-mentioned metasurface lens nano-casting process further includes: S9: applying an anti-reflective coating to the lower surface of the filled structure after curing and leveling.

[0015] In the above-mentioned metasurface lens nano-casting process, the curing in step S3 adopts UV irradiation curing technology or thermal curing technology; the curing in step S7 adopts UV irradiation curing technology or thermal curing technology.

[0016] In the above-described metasurface lens nano-casting process, the mold has an anti-stick coating on the surface that comes into contact with the first resin liquid.

[0017] In the above-described metasurface lens nanocasting process, the refractive index of the nanopillar is higher than that of the filling structure.

[0018] In the above-mentioned nano-casting process for metasurface lenses, the viscosity of the first resin liquid and the second resin liquid is ≥2cps at 25℃, such as 10cps.

[0019] The nano-casting process for metasurface lenses provided by this invention involves creating a mold with several columnar protrusions identical in shape to nanopillars. A first resin liquid is poured into the mold, a substrate is placed inside, and after curing, a filled structure with several deep pores is formed. A second resin liquid is then poured into these deep pores, and after curing, nanopillars are formed. This filled structure with several deep pores serves as the mold for preparing the nanopillars, and the nanopillars do not need to detach from the filled structure after curing. This overcomes the problem of existing processes failing to produce vertical, smooth, and highly consistent nanostructures, as well as the issues of cumbersome steps, high equipment costs, and long processing times. The metasurface lens nano-casting process provided by this invention produces metasurface lenses with high yield and good consistency, and can produce nanopillars with consistent structures according to requirements. Furthermore, the entire process is highly efficient, scalable, and low-cost, thereby promoting the industrial application of metasurface lenses in various fields. Attached Figure Description

[0020] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not intentionally drawn to scale; the focus is on illustrating the spirit of the invention.

[0021] Figure 1 This is a flowchart of the nano-casting process for metasurface lenses provided in Embodiment 1 of the present invention.

[0022] Figure 2 This is a flowchart of the nano-casting process for metasurface lenses provided in Embodiment 2 of the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but these are not intended to limit the scope of the invention.

[0024] Example 1:

[0025] The nano-casting process for metasurface lenses provided in Embodiment 1 of this invention is based on... Figure 1 This includes preparing a mold, on which several columnar protrusions with the same shape as the nanopillars are provided; It also includes the following steps: S1: Pour the first resin liquid into the mold; S2: Place the substrate on the first resin liquid; S3: The first resin liquid in the curing mold; S4: The cured first resin liquid is removed from the mold to obtain a filled structure with several deep pores that fit the nanopillars. S5: With the side of the filling structure with the deep hole opening facing upwards, pour the second resin liquid into the deep hole; S6: Cures the second resin liquid, which forms nanopillars after curing.

[0026] A metasurface lens is obtained by the nano-casting process of the metasurface lens provided in Example 1. The metasurface lens has a substrate, on which there are a plurality of nanopillars, and the nanopillars are filled with a filling structure.

[0027] The mold provided in Embodiment 1 of this invention has columnar protrusions with the same shape as the nanopillars of the metasurface lens, but slightly larger in size. The specific size difference is determined by the shrinkage of the first resin liquid. The specific calculation method for the shrinkage is a well-known technique and will not be elaborated here. This design ensures that the filling structure obtained after the first resin liquid has been cured is completely consistent with the required filling structure of the metasurface lens. In addition, due to the shrinkage, there is a certain gap between the filling structure after the first resin liquid has been cured and the mold, which facilitates demolding.

[0028] The nano-casting process for metasurface lenses provided in Embodiment 1 of this invention involves creating a mold with several columnar protrusions identical in shape to nanopillars. A first resin liquid is poured into the mold, a substrate is placed inside, and after curing, a filled structure with several deep pores is formed. A second resin liquid is then poured into these deep pores, and after curing, nanopillars are formed. This filled structure with several deep pores serves as the mold for preparing the nanopillars, and the nanopillars do not need to detach from the filled structure after curing. This overcomes the problem of existing processes failing to produce vertical, smooth, and highly consistent nanostructures, as well as the cumbersome steps, high equipment costs, and long processing times of existing processes. The metasurface lens nano-casting process provided by this invention produces metasurface lenses with high yield and good consistency, and can produce nanopillars with consistent structures according to requirements. Furthermore, the surface is relatively smooth without polishing or grinding, meeting the requirements of metasurface lenses. The entire process is highly efficient, scalable, and low-cost, thereby promoting the industrial application of metasurface lenses in various fields.

[0029] The nano-casting process for metasurface lenses provided in Embodiment 1 of this invention further includes: S7: polishing and smoothing the opening surface and nanopillars of the filling structure. In some metasurface lenses with higher flatness requirements, we can also add a polishing and smoothing process to make the surface of the metasurface lens smoother and meet customer needs.

[0030] The nano-casting process for metasurface lenses provided in Embodiment 1 of this invention further includes: S7': applying an anti-reflective coating to the opening surface of the filled structure and the surface of the nanopillars. The application of the anti-reflective coating can significantly improve light transmittance, reduce surface reflection, and simultaneously smooth the structural surface, isolate external erosion, and protect the metasurface lens structure.

[0031] In the nano-casting process of metasurface lenses provided in Embodiment 1 of the present invention, step S5 is followed by S6': covering the upper surface of the second resin liquid with a glass cover plate, the upper surface of which is coated with an anti-reflective coating. The covering with the glass cover plate flattens the surface structure of the metasurface lens, making the surface of the metasurface lens smoother. Furthermore, the anti-reflective coating on the glass cover plate can reduce reflection, increase light transmittance, and protect the metasurface lens structure.

[0032] In the nano-casting process for metasurface lenses provided in Embodiment 1 of this invention, the curing in step S3 employs either UV irradiation curing technology or thermal curing technology. The intensity and time of UV irradiation in step S3 are determined based on the amount of the first resin liquid, or the temperature and time of thermal curing are determined based on the amount of the first resin liquid. The curing in step S6 employs either UV irradiation curing technology or thermal curing technology. The intensity and time of UV irradiation in step S6 are determined based on the amount of the second resin liquid, or the temperature and time of thermal curing are determined based on the amount of the second resin liquid.

[0033] In the nano-casting process for metasurface lenses provided in Embodiment 1, the mold surface in contact with the first resin liquid is covered with an anti-stick coating. This anti-stick coating makes it easier for the cured first resin liquid to detach from the mold. The materials used for the anti-stick coating are mainly fluoropolymer coatings, silicone coatings, or ceramic coatings.

[0034] In the metasurface lens nanocasting process provided in Embodiment 1, the refractive index of the nanopillars is higher than that of the filling structure. This configuration enables the metasurface lens to more efficiently and flexibly control the phase of the light wave, achieving complete phase coverage from 0 to 2π. At the same time, the high refractive index difference strongly confines the light field within the nanopillars, effectively reducing optical crosstalk between adjacent units and improving transmission efficiency, ultimately achieving high-efficiency and high-quality beam focusing and deflection.

[0035] In the nano-casting process of the metasurface lens provided in Example 1, the viscosity of the first resin liquid is 2 cps at 25°C. The first resin liquid is cured by UV irradiation, and the intensity and duration of the UV irradiation are determined according to the design structure and dosage of the metasurface lens. If a thermosetting process is performed, the thermosetting temperature and time are determined according to the specific design structure and dosage of the metasurface lens.

[0036] In the nano-casting process of the metasurface lens provided in Example 1, the viscosity of the second resin liquid is 2 cps at 25°C. The second resin liquid is cured by UV irradiation, and the intensity and time of UV irradiation are determined according to the specific design structure and material dosage of the metasurface lens. If a thermosetting process is performed, the thermosetting temperature and time are determined according to the specific design structure and material dosage of the metasurface lens. These parameters can be obtained through a limited number of experiments and will not be elaborated here.

[0037] Example 2:

[0038] The nano-casting process for metasurface lenses provided in Embodiment 2 of this invention is based on... Figure 2 The metasurface lens includes a substrate, a plurality of nanopillars disposed on the substrate, and a filling structure filling the space between the nanopillars. The substrate includes a preparation mold and a transfer carrier plate. The mold is provided with a plurality of columnar protrusions with the same shape as the nanopillars. At least one side of the transfer carrier plate is a plane. It also includes the following steps: S1: Pour the first resin liquid into the mold; S2: Place a transfer plate on the upper surface of the first resin liquid, with the flat side of the transfer plate facing the first resin liquid; S3: The first resin liquid in the mold is cured, and the temporary bonding between the first resin liquid and the transfer carrier plate is completed at the same time. S4: The cured first resin liquid is removed from the mold to obtain a filled structure with several deep pores that fit the nanopillars. S5: With the side of the filling structure with the deep hole opening facing upwards, pour the second resin liquid into the deep hole; S6: Place the substrate on the second resin liquid; S7: Curing the second resin liquid to form nanopillars.

[0039] S8: Debond transfer carrier plate, the lower surface of the resulting filled structure is a flat surface.

[0040] A metasurface lens is obtained by the nano-casting process of the metasurface lens provided in Example 2. The metasurface lens has a substrate with a plurality of nanopillars on the substrate and a filling structure between the nanopillars.

[0041] The mold provided in Embodiment 2 of the present invention has columnar protrusions with the same shape as the nanopillars of the metasurface lens, but slightly larger in size. The specific size difference is determined by the shrinkage of the first resin liquid. The specific calculation method for the shrinkage is a well-known technique and will not be elaborated here. This design ensures that the filling structure obtained after the first resin liquid is cured is completely consistent with the required filling structure of the metasurface lens. In addition, due to the shrinkage, there is a certain gap between the filling structure after the first resin liquid is cured and the mold, which facilitates demolding.

[0042] The transfer carrier plate provided in Embodiment 2 of the present invention has at least one flat surface. Using the transfer carrier plate during the process can protect the filling structure, especially after the filling structure is detached from the mold. When the filling structure is used as a mold for the second resin liquid, it can protect the filling structure. Furthermore, the transfer carrier plate can also flatten the surface of the filling structure that contacts it, thereby eliminating the need for polishing and grinding in conventional processes, reducing steps, and improving production efficiency.

[0043] The nano-casting process for metasurface lenses provided in Embodiment 2 of this invention uses a filling structure with several deep pores as a mold for preparing nanopillars. After the nanopillars are cured, they do not need to be detached from the filling resin, thus avoiding the problem of easy damage to the nanopillars. The entire process is highly efficient, has a high yield, is scalable, and has a low cost, which can promote the industrial application of metasurface lenses in various fields.

[0044] The nano-casting process for metasurface lenses provided in Embodiment 2 of the present invention further includes: S9: applying an anti-reflective coating to the lower surface of the solidified and leveled filling structure; the lower surface is the side that contacts the translation carrier plate. The application of the anti-reflective coating can significantly improve light transmittance, reduce surface reflection, and at the same time smooth the surface of the structure, isolate external erosion, and protect the metasurface lens structure.

[0045] In the nano-casting process of metasurface lenses provided in Embodiment 2 of the present invention, the curing in step S3 adopts UV irradiation curing technology or thermal curing technology; the intensity and time of UV irradiation in step S3 are determined according to the amount of the first resin liquid, or the temperature and time of thermal curing are determined according to the amount of the first resin liquid; the curing in step S7 adopts UV irradiation curing technology or thermal curing technology; the intensity and time of UV irradiation in step S7 are determined according to the amount of the second resin liquid, or the temperature and time of thermal curing are determined according to the amount of the second resin liquid.

[0046] In the nano-casting process for metasurface lenses provided in Embodiment 2 of this invention, the mold surface in contact with the first resin liquid is covered with an anti-stick coating. The anti-stick coating makes it easier for the cured first resin liquid to detach from the mold. The materials for the anti-stick coating are mainly divided into fluoropolymer coatings, silicone coatings, or ceramic coatings.

[0047] In the high aspect ratio metasurface lens nanocasting process provided in Embodiment 2, the refractive index of the nanopillars is higher than that of the filling resin. This configuration enables the metasurface lens to more efficiently and flexibly control the phase of the light wave, achieving complete phase coverage from 0 to 2π. At the same time, the high refractive index difference strongly confines the light field within the nanopillars, effectively reducing optical crosstalk between adjacent units and improving transmission efficiency, ultimately achieving high-efficiency and high-quality beam focusing and deflection.

[0048] In the nano-casting process of the metasurface lens provided in Example 2, the viscosity of the first resin liquid is 10 cps at 25°C. The first resin liquid is cured by UV irradiation. The intensity and duration of UV irradiation are determined according to the design requirements and material usage of the metasurface lens. Specific parameters can be obtained from a limited number of experiments and will not be elaborated here. When using a thermosetting process, the thermosetting temperature and time can also be obtained from a limited number of experiments and will not be elaborated here.

[0049] In the nano-casting process of the metasurface lens provided in Example 2, the viscosity of the second resin liquid is 10 cps at 25°C. The second resin liquid is cured by UV irradiation. The intensity and duration of UV irradiation are determined based on the specific design structure and material usage of the metasurface lens, and can be obtained through a limited number of experiments, which will not be elaborated here. When a thermosetting process is used to cure the second resin liquid, the thermosetting temperature and time are determined based on the specific design requirements and material usage of the metasurface lens, and can be obtained through a limited number of experiments, which will not be elaborated here.

[0050] In summary, the nano-casting process for metasurface lenses provided in Embodiment 2 of this invention involves fabricating a mold with several columnar protrusions identical in shape to the nanopillars, preparing a transfer carrier plate with at least one flat side, pouring a first resin liquid into the mold, and allowing it to solidify to form a filled structure with several deep pores. A second resin liquid is then poured into these deep pores, a substrate is placed on top, and the process solidifies to form nanopillars. This filler structure with several deep pores serves as the mold for preparing the nanopillars, and the nanopillars do not need to be detached from the filler structure after solidification. The transfer carrier plate is then removed from the filler structure. This overcomes the problem of existing processes failing to produce vertical, smooth, and highly consistent nanostructures, as well as the issues of cumbersome steps, high equipment costs, and long processing times associated with existing processes. The nano-casting process for metasurface lenses provided by this invention produces metasurface lenses with high yield and good consistency, and can produce nanopillars with consistent structures according to requirements. Furthermore, the entire process is highly efficient, scalable, and low-cost, thereby promoting the industrial application of metasurface lenses in various fields.

[0051] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a manner common to the art; any possible variations and modifications made by those skilled in the art without departing from the technical solution of the present invention, or equivalent embodiments with equivalent changes, do not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A nano-casting process for a metasurface lens, the metasurface lens comprising a substrate, a plurality of nanopillars disposed on the substrate, and a filling structure filling the spaces between the nanopillars, characterized in that, This includes preparing a mold, on which several columnar protrusions with the same shape as the nanopillars are provided; It also includes the following steps: S1: Pour the first resin liquid into the mold; S2: Place the substrate on the first resin liquid; S3: Solidify the first resin liquid in the mold; S4: The cured first resin liquid is removed from the mold to obtain a filled structure, which has a number of deep pores that fit the nanopillars. S5: With the side of the filling structure with the deep hole opening facing upwards, pour the second resin liquid into the deep hole; S6: Curing the second resin liquid to form the nanopillars after curing.

2. The nano-casting process for metasurface lenses as described in claim 1, characterized in that, Also includes: S7: Polish and grind the opening surface of the filling structure and the nanopillars.

3. The nano-casting process for metasurface lenses as described in claim 1, characterized in that, Also includes: S7': Apply an anti-reflective coating to the opening surface of the filling structure and the surface of the nanopillar.

4. The nano-casting process for metasurface lenses as described in claim 1, characterized in that, The process includes step S6' after step S5: covering the upper surface of the second resin liquid with a glass cover plate, the upper surface of which is coated with an anti-reflective coating.

5. The nano-casting process for metasurface lenses as described in claim 1, characterized in that, The curing process in step S3 employs either UV irradiation curing technology or thermal curing technology. The curing in step S6 is performed using UV irradiation curing technology or thermal curing technology.

6. A nano-casting process for a metasurface lens, the metasurface lens comprising a substrate, a plurality of nanopillars disposed on the substrate, and a filling structure filling the spaces between the nanopillars, characterized in that, The process includes preparing a mold and a transfer carrier plate. The mold is provided with a plurality of columnar protrusions with the same shape as the nanopillars, and at least one side of the transfer carrier plate is a plane. It also includes the following steps: S1: Pour the first resin liquid into the mold; S2: Place a transfer carrier plate on the upper surface of the first resin liquid, with the plane of the transfer carrier plate facing the first resin liquid; S3: Solidify the first resin liquid in the mold, and at the same time complete the temporary bonding between the first resin liquid and the transfer carrier plate; S4: The cured first resin liquid is removed from the mold to obtain a filled structure, which has a number of deep pores that fit the nanopillars. S5: With the side of the filling structure with the deep hole opening facing upwards, pour the second resin liquid into the deep hole; S6: Place the substrate on the second resin liquid; S7: Solidify the second resin liquid to form the nanopillars; S8: Debond the transfer carrier plate to obtain a flat lower surface of the filling structure.

7. The nano-casting process for metasurface lenses as described in claim 6, characterized in that, Also includes: S9: Apply an anti-reflective coating to the lower surface of the filled structure after it has been cured and leveled.

8. The nano-casting process for metasurface lenses as described in claim 6, characterized in that, The curing in step S3 uses UV irradiation curing technology or thermal curing technology; the curing in step S7 uses UV irradiation curing technology or thermal curing technology.

9. The nano-casting process for metasurface lenses as described in claim 1 or 6, characterized in that, The mold has an anti-stick coating on the surface that comes into contact with the first resin liquid.

10. The nano-casting process for metasurface lenses as described in claim 1 or 6, characterized in that, The refractive index of the nanopillars is higher than that of the filling structure.

11. The nano-casting process for metasurface lenses as described in claim 1 or 6, characterized in that, The viscosity of the first resin liquid and the second resin liquid is ≥2cps at 25°C.

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