Visible light dual-wavelength polarization multiplexing metasurface hologram and preparation method thereof

Abstract

The application discloses a visible light dual-wavelength polarization multiplexing super surface hologram and a preparation method thereof, and relates to the technical field of micro-nano manufacturing. The super surface hologram comprises: a super atom array with a period of 450nm in x and y directions and a height of 800nm, which is formed based on a nano-imprinting technology; in the super atom array, all the super atoms are cuboid columnar structures, and the main bodies are composed of polymers doped with titanium dioxide nanoparticles; the size and position of each super atom are determined according to a GS algorithm; the GS algorithm is used for calculating phase information of a target image under corresponding wavelength polarized light; and the wavelength polarized light comprises X polarized light with a wavelength of 532nm and Y polarized light with a wavelength of 671nm. The application can solve the problems of long manufacturing process period, small scale and high cost of a traditional super surface device, and provides a new development idea for multi-color imaging technology based on super surface holography.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-nano manufacturing, in particular to a visible light dual-wavelength polarization multiplexing metasurface hologram and a preparation method thereof. BACKGROUND

[0002] A metasurface is a new type of subwavelength structure that can flexibly control the amplitude, polarization and phase of electromagnetic waves at the micro level. In the field of optics, metasurfaces have a wide range of applications, such as superlenses, holographic imaging, invisibility cloaks, and absorption enhancement devices. As a new device with information storage, encryption and transmission functions, metasurface holograms can break through the limitations of traditional holographic imaging devices, such as small field of view and large size. However, a major problem with most metasurface holograms is that they can only work at a specific single wavelength and do not have multi-wavelength imaging capabilities.

[0003] In addition, metasurfaces working in the visible light range are usually based on pure titanium dioxide (TiO2) due to its high refractive index and low extinction coefficient. The traditional manufacturing process of titanium dioxide metasurfaces can be summarized as follows: first, a TiO2 film is grown on a substrate using physical vapor deposition (PVD); then, an electron beam lithography (EBL) is used to manufacture an etching hard mask; and finally, ion beam etching (IBE) or other methods are used to etch the required columnar structure. It is not difficult to see that the above manufacturing process has a long cycle, many steps and high cost, which is not conducive to mass production and wide application of metasurface holograms. SUMMARY

[0004] The purpose of the present application is to provide a visible light dual-wavelength polarization multiplexing metasurface hologram and a preparation method thereof, which can solve the problems of long manufacturing process cycle, small scale and high cost of traditional metasurface devices, and provide a new development idea for multi-color imaging technology based on metasurface holography.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0006] A visible light dual-wavelength polarization multiplexing metasurface hologram comprises: being composed of a super atom array with a period of 450 nm in x and y directions and a height of 800 nm based on a nanoimprinting technology; all the super atoms in the super atom array are cuboid columnar structures, and the main body is composed of a polymer doped with titanium dioxide nanoparticles; the size and position of each super atom are determined according to a GS algorithm; the GS algorithm is used to calculate the phase information of a target image under corresponding wavelength polarized light; the wavelength polarized light comprises 532 nm X polarized light and 671 nm Y polarized light.

[0007] Optionally, the overall length and width of the metasurface hologram are 53.55 mu m and 45.45 mu m respectively.

[0008] Optionally, the length and width of the super atom are between 100 and 380 nm.

[0009] The application further provides a preparation method of the visible light dual-wavelength polarization multiplexing metasurface hologram, comprising:

[0010] Etching a silicon substrate to obtain a metasurface hologram silicon master mold;

[0011] Performing surface fluorination treatment on the silicon master mold;

[0012] Sequentially spin-coating and solidifying hPDMS and PDMS on the silicon master mold after fluorination treatment, and separating the completely solidified silicon master mold and PDMS submold to obtain a corresponding negative structure submold;

[0013] Spin-coating a stamping glue on the submold, then inversely clamping the two on a support substrate, then applying a downward pressure on the top of the silicon master mold while performing ultraviolet curing; the stamping glue is a polymer doped with titanium dioxide nanoparticles; the support substrate adopts a glass substrate;

[0014] Peeling off the submold to obtain a replica with the same structure as the silicon master mold, and completing the preparation of the visible light dual-wavelength polarization multiplexing metasurface hologram.

[0015] Optionally, the silicon substrate is etched to obtain a metasurface hologram silicon master mold, and the method specifically comprises:

[0016] Firstly, the silicon substrate is immersed in acetone, isopropyl alcohol and deionized water for 10 min respectively, and then the silicon substrate is blown dry on both sides using N2;

[0017] Secondly, spin-coat photoresist PMMA on the surface of the silicon substrate at a speed of 2000 rpm, and then bake at 180 DEG C for 300 s;

[0018] Thirdly, use electron beam lithography to expose the PMMA, and then develop to obtain an etching mask;

[0019] Fourthly, etching the silicon substrate using an inductively coupled plasma reactive ion etching device, and then removing the surface residual PMMA using a plasma stripper to obtain a silicon master;

[0020] Fifthly, immersing the silicon master in acetone, isopropyl alcohol and deionized water respectively for 10 minutes, and then blowing dry the front and back surfaces of the silicon master using N2 to obtain a super-hologram silicon master.

[0021] Optionally, the silicon master is subjected to surface fluorination treatment, specifically including:

[0022] Firstly, taking a proper amount of anti-sticking agent perfluorooctyltrichlorosilane in an evaporation dish;

[0023] Secondly, placing the evaporation dish and the silicon master subjected to oxygen plasma bombardment in a vacuum box together;

[0024] Thirdly, in a vacuum environment, the perfluorooctyltrichlorosilane volatilizes and adheres to the surface of the silicon master to realize surface hydrophobization.

[0025] Optionally, sequentially spin-coating and curing hPDMS and PDMS on the silicon master subjected to fluorination treatment, and separating the completely cured silicon master and PDMS master to obtain a corresponding negative structure master, specifically including:

[0026] Firstly, fixing the silicon master subjected to fluorination treatment on a support substrate using a high-temperature adhesive tape;

[0027] Secondly, spin-coating the hPDMS precursor on the silicon master at a speed of 1000 rpm, and then baking in a 70°C oven for 2 hours to realize semi-curing;

[0028] Thirdly, spin-coating the PDMS precursor on the semi-cured hPDMS at a speed of 1000 rpm, and then baking in a 100°C oven for 2 hours to realize complete curing of the hPDMS and PDMS;

[0029] Fourthly, separating the silicon master and the PDMS master, and then rinsing the PDMS master with isopropyl alcohol and deionized water respectively, and then blowing dry the front and back surfaces of the PDMS master using N2, and finally performing fluorination treatment to obtain a corresponding negative structure master.

[0030] Optionally, spin-coating imprint glue on the master, and then inverting the master and the substrate on a support substrate, and then applying downward pressure on the top of the silicon master while performing ultraviolet curing, specifically including:

[0031] First, spin the imprinting glue on the surface of the PDMS sub-mold at a speed of 1800 rpm, and then place it in a vacuum box for 5 min to exhaust the air bubbles in the contact surface between the imprinting glue and the PDMS sub-mold;

[0032] First, spin the PMMA on the glass substrate at a speed of 2000 rpm, and then bake it in a 100°C oven for 2 min to improve the adhesion between the subsequent imprinting glue and the glass substrate;

[0033] Invert the sub-mold on the glass substrate and perform UV exposure while applying a pressure of 50 kPa to achieve the curing of the imprinting glue.

[0034] According to the specific embodiments provided by the application, the following technical effects are disclosed:

[0035] The application discloses a visible light dual-wavelength polarization multiplexing super surface hologram and a preparation method thereof. The super surface hologram comprises a super atom array with a period of 450 nm in x and y directions and a height of 800 nm, which is formed based on a nano-imprinting technology. In the super atom array, all the super atoms are cuboid columnar structures, and the main bodies are composed of polymers doped with titanium dioxide nanoparticles. The size and position of each super atom are determined according to a GS algorithm. The GS algorithm is used to calculate the phase information of a target image under corresponding wavelength polarized light. The wavelength polarized light comprises X polarized light with a wavelength of 532 nm and Y polarized light with a wavelength of 671 nm. The application can solve the problems of long manufacturing process period, small scale and high cost of a traditional super surface device, and provide a new development idea for multi-color imaging technology based on super surface holography. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0037] Figure 1 It is a three-dimensional schematic diagram of the super surface hologram of the present application;

[0038] Figure 2 It is a three-dimensional schematic diagram of a single super atom in the present embodiment;

[0039] Figure 3 It is a schematic diagram of the working principle of the super surface hologram in the present embodiment;

[0040] Figure 4The images shown are far-field images of the metasurface hologram obtained in this embodiment under different wavelengths and linearly polarized light incident on the surface; (a) is the far-field energy distribution of 532nm wavelength x-linearly polarized light passing through the metasurface hologram, and (b) is the far-field energy distribution of 671nm wavelength y-linearly polarized light passing through the metasurface hologram.

[0041] Figure 5 This is a schematic diagram illustrating the principle of fluorination treatment on the surface of the silicon master mold (or PDMS sub-mold) in this embodiment;

[0042] Figure 6 This is a flowchart of the reverse nanoimprinting process in this embodiment. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The purpose of this invention is to provide a visible light dual-wavelength polarization multiplexed metasurface hologram and its preparation method, which can solve the problems of long manufacturing cycle, small scale and high cost of traditional metasurface devices, and provide a new development idea for multicolor imaging technology based on metasurface holography.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1 As shown, this invention provides a visible light dual-wavelength polarization multiplexed metasurface hologram, which can form different images under 532nm X-polarized light and 671nm Y-polarized light respectively, laying the foundation for the wide application of metasurface holograms.

[0047] Metasurface holograms are composed of periodically arranged columnar structures, each called a superatom. Superatoms at different positions correspond to the actual transmission phase at that location. Unlike traditional photolithography, nanoimprint lithography offers greater substrate compatibility, allowing the substrate to be made of glass or flexible plastic, and its shape to be planar or curved.

[0048] As one specific implementation method, the structure and fabrication process of the metasurface hologram include:

[0049] The first step is to get the silicon master of the metasurface hologram by etching the silicon substrate. The second step is to perform surface fluorination treatment on the silicon master to facilitate subsequent demolding. The third step is to spin-coat hPDMS on the silicon master in turn, and then perform baking and curing. The fourth step is to spin-coat PDMS on the surface of hPDMS, and then perform baking and curing, thereby obtaining the corresponding negative structure sub-mold. The fifth step is to spin-coat the polymer doped with TiO2 nanoparticles on the sub-mold, and then invert the two on the support substrate, and then apply downward pressure to the top of the silicon master while performing ultraviolet curing. Finally, the sub-mold is peeled off, i.e. the replica with the same structure as the silicon master is obtained.

[0050] Wherein, the dual-wavelength refers to 532nm and 671nm, and the polarization multiplexing refers to splitting and imaging of X-direction and Y-direction linearly polarized light. The super atom is a cuboid columnar structure on the surface of the substrate, and different sizes and shapes of super atoms have different optical responses to X-direction linearly polarized and Y-direction linearly polarized incident light, so that independent regulation of X-direction and Y-direction transmission phases can be realized. All super atoms have the same height and arrangement period. All super atoms are dielectric materials.

[0051] For the size and position of the super atom, the phase information of the target image A under the X-polarized light of 532nm and the phase information of the target image B under the Y-polarized light of 671nm are extracted by GS (Gerchberg-Saxton) algorithm. The actual transmission phase under the incidence of two-wavelength polarized light is obtained by simulating the super atom. Further, the designed metasurface contains the phase information of the two target images. This means that each super atom contains two phase information: the first one is the phase information of the target image A at this position under the incidence of X-polarized light of 532nm. The second one is the phase information of the target image B at this position under the incidence of Y-polarized light of 671nm. According to the above phase information, suitable super atoms are selected and placed at different positions to finally form a complete metasurface hologram.

[0052] As a more detailed preparation process, the etching process mainly includes: relying on electron beam lithography (EBL) technology, obtaining the etching mask corresponding to the required metasurface hologram on the surface of the silicon substrate. Relying on inductively coupled plasma etching (ICP) technology, etching the metasurface hologram on the surface of the silicon substrate, that is, the silicon master mold. Then the surface of the silicon master mold also needs to be fluorinated to facilitate subsequent demolding. The fluorination process mainly includes: taking an appropriate amount of anti-sticking agent perfluorooctyltrichlorosilane in an evaporation dish, and placing the evaporation dish and the silicon master mold (or sub-mold) subjected to oxygen plasma bombardment in a vacuum box. In a vacuum environment, perfluorooctyltrichlorosilane volatilizes and adheres to the surface of the silicon master mold (or sub-mold), thereby realizing surface fluorination. The sub-mold manufacturing process includes: spin coating hPDMS precursor on the silicon master mold, then baking until semi-cured, then spin coating PDMS precursor on the semi-cured hPDMS, and finally baking until the two are completely cured. Remove the silicon master mold, and then fluorinate the sub-mold as described above. Spin coating the polymer doped with titanium dioxide nanoparticles, that is, the imprinting glue, on the front surface of the sub-mold. By adjusting the coating rate and time, the residual thickness of the imprinting glue can be adjusted. The reverse nanoimprint process includes: inverting the sub-mold on the glass substrate, applying a suitable pressing force while performing ultraviolet light exposure, thereby realizing the curing of the imprinting glue. Finally, remove the sub-mold to obtain a replica of the silicon master mold, that is, the required metasurface hologram.

[0053] In the above process, when the liquid fluorine-based anti-sticking agent and the silicon master mold (or PDMS sub-mold) subjected to plasma bombardment are placed in a vacuum environment at the same time, the anti-sticking agent volatilizes and adheres to the surface of the silicon master mold (or PDMS sub-mold), thereby realizing the anti-sticking effect. Moreover, the PDMS sub-mold is a double-layer stepped structure, wherein the hPDMS with high Young's modulus is in direct contact with the silicon master mold, and the surface of the hPDMS is covered with PDMS.

[0054] Therefore, the technical scheme has the following beneficial effects:

[0055] (1) The cuboid super atom adopted in the present application has high design freedom and can independently control the transmission phase of different polarized light, thereby realizing polarization multiplexing function.

[0056] (2) The present application realizes dual-color holographic display based on 532nm X-polarized light and 671nm Y-polarized light, thereby enriching the information storage and other functions of the metasurface hologram.

[0057] (3) Based on the polarization control principle, the present application realizes the visible light dual-wavelength polarization multiplexing function through a single-layer metasurface. Compared with the traditional imaging system, it has smaller volume, lower complexity and higher integration.

[0058] (4) The present application adopts a polymer doped with titanium dioxide nanoparticles as the imprinting glue. The good fluidity of the material lays the foundation for the direct imprinting molding of the super surface hologram. At the same time, the material has high refractive index and low extinction coefficient in the visible light band, which provides guarantee for the imaging quality of the super surface hologram.

[0059] (5) The present application adopts a simple and low-cost surface fluorination method to realize the hydrophobization of the silicon master mold and the sub-mold. The specific operation process is as follows: first, take an appropriate amount of anti-sticking reagent perfluorooctyltrichlorosilane in an evaporating dish. Second, place the evaporating dish and the silicon master mold (or sub-mold) subjected to oxygen plasma bombardment in a vacuum box. Third, in a vacuum environment, perfluorooctyltrichlorosilane volatilizes and adheres to the surface of the silicon master mold (or sub-mold), thereby realizing surface fluorination.

[0060] (6) The present application adopts double-layer PDMS as the sub-mold. The hPDMS in direct contact with the silicon master mold has a higher Young's modulus, and is not prone to deformation when imprinting high aspect ratio structures.

[0061] (7) The present application adopts reverse imprinting. The specific operation process is as follows: first, place the sub-mold face (i.e. with the structure surface) upwards on the spin coater. Second, drop an appropriate amount of imprinting glue on the front surface of the sub-mold using a glue head dropper, and precisely control the thickness of the imprinting glue on the front surface of the sub-mold, i.e. the thickness of the residual layer, by adjusting the spin coating speed and time. Third, cover the glass substrate on the front surface of the sub-mold for imprinting. The traditional forward imprinting process is to first spin coat the imprinting glue on the glass substrate, and then press the sub-mold face downwards on the glass substrate for imprinting. In this process, the residual layer is too thick, which is not conducive to the final imaging quality of the super surface hologram.

[0062] Based on the above technical solutions, the following specific embodiments are provided as shown below.

[0063] As shown in Figure 1 , the overall length and width of the visible light dual-wavelength polarization multiplexing super surface hologram based on nanoimprint technology are 53.55 μm and 45.45 μm, respectively. The upper surface is composed of super atom arrays with a period of 450 nm in the x and y directions and a height of 800 nm. The cross-section of all super atoms is rectangular, which makes them have different optical responses to x and y direction linearly polarized incident light. Therefore, by changing the size of the super atom cross-section, the transmission phase of x and y direction linearly polarized light can be independently controlled. As shown in Figure 2 , the main body of the super atom is composed of a polymer with titanium dioxide nanoparticles distributed inside, and the length and width of the cross-section are between 100 and 380 nm. As shown in Figure 3As shown, the above-mentioned metasurface hologram can realize wavelength polarization multiplexing for 532 nm x-polarized incident light and 671 nm y-polarized incident light, and present two images of different colors in the plane. Figure 2 and Figure 3 In the above-mentioned formulas, λ represents the wavelength of incident light, P represents the period of superatoms, H represents the height of superatom structure, W represents the width of superatom, and L represents the length of superatom.

[0064] The phase information of the two target images under 532 nm x-polarized light and 671 nm y-polarized light is extracted by using the GS (Gerchberg-Saxton) algorithm. Through simulation calculation, the actual transmission phase of all superatoms under 532 nm x-polarized light and 671 nm y-polarized light is obtained. According to the phase information of the two images, superatoms with the same phase information are placed in different positions in turn until a complete metasurface hologram is formed. The far-field energy distribution of 532 nm x-polarized light passing through the metasurface hologram is shown in part (a) of Figure 4 , and the far-field energy distribution of 671 nm y-polarized light passing through the metasurface hologram is shown in part (b) of Figure 4 .

[0065] Based on the size of each superatom, the silicon substrate is etched to obtain a silicon master mold of the metasurface hologram. The detailed process is as follows: first, immerse the silicon substrate in acetone, isopropyl alcohol and deionized water for 10 min, and then blow dry the front and back surfaces of the silicon substrate with N2. Second, spin coat photoresist PMMA on the surface of the silicon substrate at a speed of 2000 rpm, and then bake at 180°C for 300 s. Third, expose the PMMA using electron beam lithography (EBL), and then develop to obtain an etching mask. Fourth, etch the silicon substrate using an inductively coupled plasma reactive ion etching (ICP-RIE) device, and then remove the residual PMMA on the surface using a plasma stripper, thereby obtaining a silicon master mold. Fifth, immerse the silicon master mold in acetone, isopropyl alcohol and deionized water for 10 min, and then blow dry the front and back surfaces of the silicon master mold with N2.

[0066] Before using the silicon master mold (or sub-mold), it needs to be subjected to surface fluorination treatment (i.e. surface hydrophobization treatment) to facilitate subsequent demolding. First, take an appropriate amount of anti-sticking agent perfluorooctyltrichlorosilane in an evaporating dish. Second, place the evaporating dish and the silicon master mold (or sub-mold) subjected to oxygen plasma bombardment in a vacuum box together, as shown in Figure 5The third step, the perfluorooctyltrichlorosilane volatilizes and adheres to the surface of the silicon master (or sub-mold) under vacuum environment, thereby realizing the hydrophobization of the surface.

[0067] Figure 6 The schematic diagram of the reverse nanoimprint process is shown. The first step, the fluorinated silicon master is fixed on the support substrate (not shown in the figure) using high-temperature adhesive tape. The second step, the hPDMS precursor is first spin-coated on the silicon master at a speed of 1000 rpm, and then baked in a 70°C oven for 2h to realize semi-curing. The third step, the PDMS precursor is first spin-coated on the semi-cured hPDMS at a speed of 1000 rpm, and then baked in a 100°C oven for 2h to realize complete curing of the hPDMS and PDMS. The fourth step, the silicon master and PDMS sub-mold are separated, and then the PDMS sub-mold is washed with isopropanol and deionized water respectively, and then blown dry with N2 on both sides of the PDMS sub-mold, and finally fluorinated. The fifth step, the imprinting glue (i.e. polymer doped with titanium dioxide nanoparticles) is first spin-coated on the surface of the PDMS sub-mold at a speed of 1800 rpm, and then placed in a vacuum box for 5min to remove the air bubbles in the contact surface between the imprinting glue and the PDMS sub-mold. The sixth step, PMMA is first spin-coated on the glass substrate at a speed of 2000 rpm, and then baked in a 100°C oven for 2min to improve the adhesion between the subsequent imprinting glue and the glass substrate. The seventh step, the sub-mold is inverted on the glass substrate, and ultraviolet light exposure is performed while applying a pressure of 50kPa, thereby realizing the curing of the imprinting glue. The eighth step, the glass substrate and the PDMS sub-mold are separated, and the replica remains on the surface of the glass substrate.

[0068] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0069] The principles and implementation manners of the present application are described by using specific examples in the specification. The above description of the embodiments is only for the purpose of helping to understand the core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range will be changed. In view of the above, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A visible light dual-wavelength polarization multiplexed metasurface hologram, characterized in that, include: Based on nanoimprinting technology, it consists of a superatomic array with a period of 450 nm in both the x and y directions and a height of 800 nm. In this superatomic array, all superatoms are cuboid columnar structures, and the main body is composed of a polymer doped with titanium dioxide nanoparticles. The size and position of each superatom are determined according to the GS algorithm. The GS algorithm is used to calculate the phase information of the target image under corresponding wavelength polarized light. The wavelength polarized light includes 532 nm X-polarized light and 671 nm Y-polarized light. Methods for preparing visible light dual-wavelength polarization multiplexed metasurface holograms include: The silicon substrate is etched to obtain a metasurface holographic silicon master model; The silicon master mold is subjected to surface fluorination treatment; hPDMS and PDMS were spin-coated and cured sequentially on the fluorinated silicon master mold, and the fully cured silicon master mold and PDMS sub-mold were separated to obtain the corresponding negative structure sub-mold. The imprinting adhesive is spin-coated onto the sub-mold, and then both are inverted onto the support substrate. Next, downward pressure is applied to the top of the silicon master mold while UV curing is performed. The imprinting adhesive is a polymer doped with titanium dioxide nanoparticles. The support substrate is a glass substrate. The sub-mold was peeled off to obtain a replica with the same structure as the silicon master mold, thus completing the fabrication of a visible light dual-wavelength polarization multiplexed metasurface hologram.

2. The visible light dual-wavelength polarization multiplexed metasurface hologram according to claim 1, characterized in that, The overall length and width of the metasurface hologram are 53.55 μm and 45.45 μm, respectively.

3. The visible light dual-wavelength polarization multiplexed metasurface hologram according to claim 1, characterized in that, The length and width of the superatoms are between 100 and 380 nm.

4. The visible light dual-wavelength polarization multiplexed metasurface hologram according to claim 1, characterized in that, Etching the silicon substrate yields a metasurface holographic silicon master model, specifically including: The first step is to immerse the silicon substrate in acetone, isopropanol and deionized water for 10 minutes respectively, and then use N2 to dry both sides of the silicon substrate. The second step is to spin-coat PMMA photoresist onto the silicon substrate at a speed of 2000 rpm, and then bake it at 180°C for 300 seconds. The third step involves exposing the PMMA using electron beam lithography, followed by development to obtain an etching mask; The fourth step involves etching the silicon substrate using an inductively coupled plasma reactive ion etching (ICP-RI) system, followed by removing residual PMMA from the surface using a plasma resist remover to obtain the silicon master mold. The fifth step involves immersing the silicon master mold in acetone, isopropanol, and deionized water for 10 minutes each, and then drying both sides of the silicon master mold with N2 to obtain the metasurface holographic silicon master mold.

5. The visible light dual-wavelength polarization multiplexed metasurface hologram according to claim 1, characterized in that, The silicon master mold undergoes surface fluorination treatment, specifically including: First, take an appropriate amount of the anti-sticking reagent perfluorooctyltrichlorosilane into an evaporating dish; The second step is to place the evaporation dish and the silicon master mold bombarded by oxygen plasma together in a vacuum chamber; The third step involves perfluorooctyltrichlorosilane volatilizing and adhering to the surface of the silicon master mold in a vacuum environment, thereby achieving surface hydrophobicity.

6. The visible light dual-wavelength polarization multiplexed metasurface hologram according to claim 1, characterized in that, hPDMS and PDMS were sequentially spin-coated and cured onto the fluorinated silicon master mold. The fully cured silicon master mold and PDMS sub-mold were then separated to obtain the corresponding negative structure sub-mold, specifically including: The first step is to use high-temperature tape to fix the fluorinated silicon master mold onto the support substrate; The second step is to spin-coat the hPDMS precursor onto the silicon master mold at a speed of 1000 rpm, and then bake it in a 70°C oven for 2 hours to achieve semi-curing. The third step is to spin-coat the PDMS precursor onto the semi-cured hPDMS at a speed of 1000 rpm, and then bake it in an oven at 100°C for 2 hours to achieve complete curing of hPDMS and PDMS. The fourth step involves separating the silicon master mold and the PDMS sub-mold. The PDMS sub-mold is then rinsed with isopropanol and deionized water, respectively. Subsequently, both sides of the PDMS sub-mold are dried with N2, and finally, fluorination is performed to obtain the corresponding negative structure sub-mold.

7. The visible light dual-wavelength polarization multiplexed metasurface hologram according to claim 1, characterized in that, The imprinting adhesive is spin-coated onto the sub-mold, and then both are inverted onto the support substrate. Next, downward pressure is applied to the top of the silicon master mold while UV curing is performed. Specifically, this includes: First, spin-coat the embossing adhesive onto the surface of the PDMS sub-mold at a speed of 1800 rpm, and then place it in a vacuum chamber for 5 minutes to remove air bubbles in the contact surface between the embossing adhesive and the PDMS sub-mold. First, PMMA was spin-coated onto a glass substrate at 2000 rpm, and then baked in a 100°C oven for 2 minutes to improve the adhesion between the subsequent imprinting adhesive and the glass substrate. The sub-mold is placed upside down on a glass substrate, and ultraviolet light is applied while a pressure of 50 kPa is applied to achieve curing of the imprinting adhesive.

Images