Solution for nanograting imprinting using laser polarization state

Abstract

The application discloses a solution for realizing nano-grating imprinting by using laser polarization state, wherein a simple structure is designed, laser-induced nano-grating is used to manufacture super-resolution patterns, the nano-grating remodeling strength and orientation are changed by adjusting laser wavelength, power and polarization direction, two methods for adjusting the polarization state of the illuminating white light to realize color regulation are provided, sensitive sensing of the polarization is realized, and high-resolution and high-saturation colors with a spatial resolution of 0.5 microns are obtained. The formed nano-grating has a polarization regulation effect on reflected light, by using the polarization maintaining and rotating characteristics of the nano-grating on linearly polarized white light, laser polarization states with an angular resolution of 10 degrees can be identified in pixels with a spatial resolution of 0.5 microns, and super-high-density optical storage is realized. Compared with the existing SOI (Silicon-On-Insulator) etching process, the solution has a simple manufacturing method and does not have a complex process.

Description

Technical Field

[0001] This invention relates to the field of laser-sensing periodic structures and color display technology, specifically to a solution for realizing nanograting imprinting using laser polarization states. Background Technology

[0002] Color, as a crucial sensory medium, plays a vital role across various industries. The continuous development of micro-sodium technology and materials has transformed light manipulation techniques from passively utilizing the limited optical properties of natural materials to actively constructing metamaterials with specific optical characteristics, among which plasma color technology holds immense potential. Utilizing subwavelength plasma structures, different geometric dimensions can be designed to selectively enhance or impede light at arbitrary resonant wavelengths, achieving near-field and far-field manipulation of the light field. These periodic nanoparticles, nanorods, or nanopores are mostly prepared using electron beam etching or ion beam etching methods, which are expensive, cannot be mass-produced, and lack dynamic tunability. Laser-induced periodic structures (LIPSs) technology can directly fabricate nanograting structures on the surfaces of different bulk materials, avoiding complex photolithography processes. Although it can achieve subwavelength spatial resolution imprinting of polarization orientation, it primarily focuses on fabricating two-dimensional ordered linear microstructures, making it difficult to achieve rich color display. Therefore, in the fields of color display and optical storage, the practical application of this laser direct-writing technology in polarization state recognition and super-resolution polarization imprinting requires further exploration. Summary of the Invention

[0003] In view of this, in order to solve the above-mentioned problems in the prior art, the present invention proposes a solution for realizing nanograting imprinting using laser polarization state, and applies it to super-resolution color sensitive display and ultra-high density optical storage.

[0004] The present invention solves the above problems through the following technical means:

[0005] On one hand, this invention provides a sample for nanograting imprinting using laser polarization states. The sample, from bottom to top, comprises a substrate, a metal thin film layer, a dielectric isolation layer, and a metal nano-island layer. The substrate serves as a support and can be a rigid, flat material such as glass or silicon wafer. The metal thin film layer has a thickness of 100 nm or more and can be made of metals such as gold, silver, platinum, or aluminum, deposited on the substrate by vapor deposition or ion sputtering. The dielectric isolation layer can be a flexible or rigid material. The flexible material can be an organic thin film, such as PMMA, PVP, or PVA, prepared by spin coating on the metal thin film layer, with different film thicknesses achieved by controlling the spin coating speed and time. The rigid material can be glass or ceramic, such as silicon oxide, aluminum oxide, calcium nitride, or calcium carbide, prepared by vapor deposition or chemical vapor deposition. The metal nano-island layer is prepared by particle sputtering and can be made of metals such as gold, silver, platinum, or aluminum. The size of the metal nanoparticles on the dielectric isolation layer is controlled by adjusting the sputtering time and current.

[0006] On the other hand, the present invention also provides a laser direct writing device for realizing nano-grating imprinting using laser polarization state, including a femtosecond laser system, a laser polarization adjustment device, a shutter, a laser focusing device, a micro-sodium displacement stage, and a PC with a laser direct writing control program installed; the sample is placed on the micro-sodium displacement stage, with the metal nano-islands of the sample facing the objective lens of the laser focusing device; the laser beam emitted by the femtosecond laser system passes sequentially through the laser polarization adjustment device, the shutter, and the laser focusing device, and is focused onto the metal nano-islands of the sample by the laser focusing device; the laser direct writing control program controls the micro-sodium displacement stage and the shutter, and the pattern is written by moving the micro-sodium displacement stage.

[0007] By changing the wavelength of the femtosecond laser, the intensity of the reshaping and imprinting of the metal nanoislands varies, resulting in different morphologies and thus controlling the pattern to present different colors.

[0008] By varying the power of the femtosecond laser, the reshaping and imprinting of the metal nanoislands by different power lasers can be made to differ, resulting in different morphologies and thus controlling the pattern to present different colors.

[0009] By changing the polarization state of the femtosecond laser, the orientation and arrangement of the metal nanoparticles reshaped into metal nano islands by lasers with different polarization directions are different, thereby controlling the pattern to present different colors.

[0010] The binary image is imported into the laser direct writing control program, which guides the micro-sodium displacement stage to move on the 2D plane according to the pattern requirements. By controlling the shutter switch, the laser writing is adjusted or turned off so that the femtosecond laser can directly write discontinuous patterns.

[0011] The resolution can be adjusted by setting the step size of the micro-sodium displacement stage to control the pixel size.

[0012] Furthermore, this invention also provides a detection mechanism for nano-grating imprinting using laser polarization states, achieving a color-sensitive response to polarization. The detection mechanism includes two types: the first type includes a first natural light source, a first adjustable analyzer, and a first observation device; incident natural light from the first natural light source is perpendicularly irradiated onto the laser-imprinted image, and the first adjustable analyzer is placed in the reflected light path. Adjusting the polarization direction of the first adjustable analyzer obtains linearly polarized reflected light with different polarization directions. Linearly polarized reflected light with different polarization directions can display different colors. The color change of the pattern under different polarization angles is observed through the first observation device. The second type includes a second natural light source, a first adjustable polarizer, and a second observation device; incident natural light from the second natural light source is perpendicularly irradiated onto the first adjustable polarizer, and then onto the laser-imprinted image. Adjusting the angle of the transmission axis of the first adjustable polarizer changes the polarization direction of the white light, achieving white light with different polarization directions irradiating the imprinted image. The color change of the pattern under white light irradiation with different polarization directions is observed through the second observation device. Both types of patterns can produce color patterns with identical effects.

[0013] Furthermore, this invention also provides an orthogonal polarization analyzer for detecting nanogratings using laser polarization states, identifying the angular resolution of laser polarization states. The orthogonal polarization analyzer includes a third natural light source, a second adjustable polarizer, a second adjustable analyzer, and a third observation device. The incident natural light from the third natural light source is adjusted to linear polarization by the second adjustable polarizer and then illuminates the laser-etched pattern. The reflected light is then observed through the second adjustable analyzer and the third observation device to observe the laser-etched pattern. The transmission axis of the second adjustable analyzer is always perpendicular to the transmission axis of the second adjustable polarizer. Under this device, the laser-etched pattern exhibits different brightness and darkness phenomena. Only when the vector direction of the laser-etched nanograting is aligned with or perpendicular to the transmission axis of the second adjustable polarizer, the polarization direction of the reflected light is consistent with the polarization direction of the incident light. The reflected light is not observable through the second adjustable analyzer and appears black. When the vector direction of the laser-etched nanograting is between 0° and 90° from the transmission axis of the second adjustable polarizer, the polarization direction of the reflected light rotates, forming an angle with the polarization direction of the incident light. Therefore, the reflected light can still pass through the second adjustable analyzer, and the pattern shape can be observed. The rotation capability is maximum (45°) and the reflective light transmittance is maximum, as is the pattern brightness, when the nanograting vector direction forms a 45° angle with the transmission axis of the adjustable polarizer. Nine polarization states and a 10° angular resolution can be achieved on a 0.5 μm × 0.5 μm pixel, enabling ultra-high-density optical storage.

[0014] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0015] This invention utilizes laser-induced nanogratings to fabricate super-resolution patterns. By adjusting the laser wavelength, power, and polarization direction to alter the reshaping intensity of nanoparticles and the orientation of the nanograting, two methods are proposed to regulate the polarization state of illuminating white light, achieving color sensitivity to polarization and obtaining high-resolution, high-saturation colors with a spatial resolution of 0.5 micrometers. The formed nanograting exhibits polarization-preserving and rotational properties for polarized light, enabling the identification of laser polarization states with a spatial resolution of 0.5 micrometers and an angular resolution of 10°, thus achieving ultra-high-density optical storage. Compared to existing SOI (Silicon-On-Insulator) etching processes, the method described in this application is simpler, requiring no complex etching processes to obtain near-diffraction-limited micro-sodium-scale patterns and ultra-high-density optical storage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the sample structure for nanograting imprinting using laser polarization state according to the present invention;

[0018] Figure 2 This is a transmission electron microscope (TEM) image of the gold nanoislands on the top layer of the sample of this invention;

[0019] Figure 3 This is a schematic diagram of the laser direct writing device for realizing nanograting imprinting using laser polarization state according to the present invention;

[0020] Figure 4 This is a diagram illustrating the effect of focusing laser beams of different polarization states onto gold nanoislands according to the present invention.

[0021] Figure 5 This is a schematic diagram of the first detection mechanism for realizing nanograting imprinting using laser polarization state according to the present invention;

[0022] Figure 6 This is a schematic diagram of the second detection mechanism for realizing nanograting imprinting using laser polarization state according to the present invention;

[0023] Figure 7This invention is a color map of patterns written with different laser wavelengths and the same laser power under white light with the same polarization direction.

[0024] Figure 8 This is a color map of the pattern produced by this invention observed under different polarized white light;

[0025] Figure 9 This is a schematic diagram of the orthogonal polarization analyzer, the detection mechanism for realizing nanograting imprinting using laser polarization state, according to the present invention.

[0026] Figure 10 This is an image showing the effect of the ultra-high density optical storage produced by this invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Sample; 11. Substrate; 12. Metal thin film layer; 13. Dielectric isolation layer; 14. Metal nano-island layer; 21. Femtosecond laser system; 22. Laser polarization adjustment device; 221. 1 / 2 glass slide; 222. 1 / 4 glass slide; 23. Shutter; 24. Laser focusing device; 241. Total reflection mirror; 242. Objective lens; 25. Micro-sodium displacement stage; 26. PC; 31. First adjustable analyzer; 32. First observation device; 41. First adjustable polarizer; 42. Second observation device; 51. Second adjustable analyzer; 52. Third observation device; 53. Second adjustable polarizer. Detailed Implementation

[0029] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Please see Figure 1 This invention provides a sample 1 for nanograting imprinting using laser polarization state. The sample 1 comprises, from bottom to top, a substrate 11, a metal thin film layer 12, a dielectric isolation layer 13, and a metal nano-island layer 14. The substrate 11 is a glass substrate; the metal thin film layer 12 is made of gold; the dielectric isolation layer 13 is an organic thin film, made of PMMA; and the metal nano-island layer 14 is made of gold.

[0032] Preparation method: A gold thin film layer is deposited on the substrate 11 material by vapor deposition. The substrate 11 with the gold film is placed on a spin coater. The organic PMMA is prepared into a solution, and the dielectric isolation layer 13 is prepared by spin coating. Different spin coating times and speeds are set according to the required thickness. Then, a 30 nm thick gold nanoislands are prepared on the sample 1 after the PMMA dielectric isolation layer 13 is deposited using a sputtering apparatus. Please refer to [reference needed]. Figure 2 Transmission electron microscopy (TEM) image of the top gold nanoislands, with a scale bar of 100 nm.

[0033] Example 2

[0034] Please refer to Figure 3 The present invention provides a laser direct writing device for realizing nanograting imprinting using laser polarization state, including a femtosecond laser system 21, a laser polarization adjustment device 22, a shutter 23, a laser focusing device 24, a micro sodium displacement stage 25, and a PC 26 with laser direct writing control program installed. The laser focusing device 24 is a fluorescence microscope.

[0035] The laser pulse transmission path sequentially passes through a femtosecond laser system 21, a laser polarization adjustment device 22, a shutter 23, a fluorescence microscope, and a micro-sodium displacement stage 25. The femtosecond laser system 21 outputs femtosecond pulsed mode-locked laser light, and the laser polarization adjustment device 22 generates different polarization states of the femtosecond pulsed mode-locked laser light. The polarized light with different polarization states passes through the shutter 23 and couples into the objective lens 242 of the fluorescence microscope, focusing on the surface of the metal nano-island layer 14. The sample 1 is placed on the micro-sodium displacement stage 25, and the laser acts on the metal nano-island layer 14 of the sample 1. The high energy of the femtosecond pulsed mode-locked laser reshapes the metal nano-islands into metal nanoparticles, which then exhibit a regular arrangement, forming a nano-grating structure, achieving nanoscale imprinting. A PC 26 controls the movement of the micro-sodium displacement stage 25, ensuring the laser acts on a designated area. The shutter 23 controls the on / off state of the laser, enabling direct writing of single pixels and discontinuous areas.

[0036] The laser polarization adjustment device 22 includes a half glass plate 221 and a quarter glass plate 222, wherein the femtosecond pulse mode-locked laser passes through the half glass plate 221 and the quarter glass plate 222 in sequence, and different combinations are obtained by rotating the two glass plates to control the polarized light with different polarization states.

[0037] The micro-sodium displacement stage 25 and the shutter 23 are controlled by the PC 26, which installs the laser direct writing control program. The laser direct writing control program controls the opening and closing of the shutter 23 and the horizontal movement of the micro-sodium displacement stage 25. Specifically, one opening and closing of the shutter 23 completes the etching of one pixel, and the micro-sodium displacement stage 25 moves the sample 1 to complete the etching of different areas.

[0038] Laser reshaping of metal nanoislands results in large-scale, irregularly ellipsoidal gold particles. Due to the laser-induced formation of a nanograting from this large-scale gold particle array, the reshaped nanoislands are arranged in a regular nanograting structure. Incident light illuminating the nanograting is decomposed into two components: one parallel to the nanograting vector direction and the other perpendicular to it. The polarization state of the reflected light is determined by the superposition of these two components with a phase difference. The resonance peak of the component perpendicular to the nanograting vector direction is around 600 nm, while that of the component parallel to the nanograting vector direction is around 780 nm. By adjusting the polarization angle of the incident light, the magnitudes of these two components can be controlled, thereby adjusting the resonance peaks and achieving different color displays.

[0039] By continuously varying the incident laser wavelength from 400 nm to 900 nm, the high energy of femtosecond pulsed mode-locked lasers was used to reshape metal nanoislands into metal nanoparticles with different morphologies. Due to the high energy of shorter wavelengths, the effect of shorter wavelengths is more pronounced at the same power. The reshaped metal nanoparticles exhibit a regular arrangement to form a nanograting, achieving nanoscale imprinting.

[0040] By continuously changing the power of the incident laser from 0.1mW, the high energy of the femtosecond pulse mode-locked laser is used to reshape the metal nanoislands into metal nanoparticles of different morphologies, which then exhibit a regular arrangement to form a nanograting, thus achieving nanoscale imprinting.

[0041] Adjusting the polarization adjustment device changes the polarization direction of the incident laser (0°~180°), thereby changing the arrangement orientation of the metal nano-islands after they are reshaped into metal particles, and realizing nanoscale imprinting in different directions.

[0042] The binary image to be imprinted can be split by color. The split images are imported into the laser direct writing control program. Each split image is set with a set of parameters for laser wavelength, laser power, and laser polarization direction according to different colors. The laser direct writing control program then links the opening and closing of the shutter 23 and the movement of the sample 1 by the micro-sodium displacement stage 25 to complete the imprinting of the pattern on the sample 1.

[0043] The pixel can be adjusted by adjusting the distance of a single step of the laser displacement stage, and a resolution of 0.5 micrometers × 0.5 micrometers can be achieved.

[0044] Please see Figure 4 , Figure 4The images illustrate the effects of focusing laser beams with different polarization states onto gold nanoislands. Figure a shows laser writing with 0° polarization, Figure b shows laser writing with 45° polarization, Figure c shows laser writing with 90° polarization, and Figure d shows laser writing with 135° polarization. The figures clearly show that the gold nanoislands are reshaped into directional particles under the influence of the laser, and these particles exhibit a regular arrangement, forming a nanoscale grating. The vector direction of the grating is parallel to the laser polarization direction.

[0045] Example 3

[0046] This invention also provides a detection mechanism for nanograting imprinting using laser polarization state, which controls the color. There are two schemes; the first scheme: [See details]. Figure 5 The detection mechanism includes a first natural light source, a first adjustable analyzer 31, and a first observation device 32; wherein the first natural light source is a first halogen lamp, and the first observation device 32 is a first microscope. Natural light from the first halogen lamp is perpendicularly irradiated onto the laser-etched image. The first adjustable analyzer 31 is placed in the reflected light path, and the angle of the transmission axis of the first adjustable analyzer 31 is adjusted to allow reflected light with different polarization directions to pass through. The color change of the pattern in the etched image at different analysis angles is observed through the first microscope. Second scheme: Please refer to [link / reference]. Figure 6 The detection mechanism includes a second natural light source, a first adjustable polarizer 41, and a second observation device 42; wherein the second natural light source is a second halogen lamp, and the second observation device 42 is a second microscope. Natural light from the second halogen lamp is perpendicularly irradiated onto the first adjustable polarizer 41, and then onto the laser-etched image. Adjusting the angle of the transmission axis of the first adjustable polarizer 41 changes the polarization direction of the white light, allowing white light with different polarization directions to irradiate the etched image. The color change of the pattern under white light irradiation with different polarization directions is observed through the second microscope. Since different laser parameters etched onto sample 1 result in different reshaped morphologies and arrangement orientations of the metal nanoparticles, both detection mechanisms can change the image color by adjusting the angle of the polarizer's transmission axis, achieving polarization-sensitive color response and control.

[0047] Please refer to the effect of this embodiment. Figure 7The graph above shows the horizontal axis representing the power of a 750nm, 0° polarized laser, and the vertical axis representing the polarization direction of the incident polarized white light. Since the angle between the polarization direction of the white light and the grating structure is symmetrically distributed in the vector direction, only the 0°-90° polarized white light illumination pattern needs to be shown. The pattern does not have rich colors under natural light, but it displays different colors under natural light and under white light with different polarization directions, indicating that the written pattern has obvious polarization sensitivity. The graph below shows the horizontal axis representing the laser power, and the vertical axis representing different laser wavelengths. The images are all observed under 0° polarized white light. It is clear from the graph that under white light with the same polarization direction, the patterns written with different laser wavelengths and the same laser power have different colors.

[0048] Please refer to the effect of this embodiment. Figure 8 The pattern is divided into different images according to the desired colors to be etched. Each image is configured with corresponding laser parameters, with a pixel spacing of 700 nm and a laser direct-writing area of ​​280 μm × 280 μm. The pattern is then written into the image using the laser direct-writing device according to the set laser parameters. The pattern exhibits rich colors when observed under 0° polarized white light, but the colors under 90° polarized white light are completely different, demonstrating significant polarization sensitivity. The veins in the leaves are clearly visible, with a minimum spacing of 700 nm, approaching the optical diffraction limit, achieving super-resolution display.

[0049] Example 4

[0050] This invention also provides an orthogonal polarization analyzer for detecting nanograting imprints using laser polarization states, and performing polarization state resolution analysis. Please refer to [link to relevant documentation]. Figure 9The orthogonal polarization analyzer of the detection mechanism includes a third natural light source, a second adjustable polarizer 53, a second adjustable analyzer 51, and a third observation device 52. The incident natural light irradiated by the third natural light source is adjusted to linearly polarized light after passing through the second adjustable polarizer 53 and irradiating the laser-etched pattern. The reflected light then passes through the second adjustable analyzer 51 and the third observation device 52 to observe the laser-etched pattern. The transmission axis of the second adjustable analyzer 51 is always perpendicular to the transmission axis of the second adjustable polarizer 53, forming an orthogonal polarization analyzer. The nanograting has a modulating effect on polarized light. When the incident polarized white light is parallel or perpendicular to the vector direction of the nanograting, the polarization direction of the reflected light remains consistent with that of the incident light, exhibiting polarization-preserving properties. Therefore, the reflected light is filtered out after passing through the second adjustable analyzer 51. The modulating effect on the polarized white light is greatest when the incident polarized white light forms a 45° angle with the vector direction of the nanograting, rotating the polarization direction of the reflected light 45° towards the vector direction of the nanograting. When the angle is less than 45°, the rotation ability of the polarized light is weaker, and the polarization direction of the reflected light forms an angle less than 45° with that of the incident light. Therefore, light still passes through the analyzer after the reflected light passes through, and the pattern can be observed. By utilizing the polarization-preserving and rotation properties of the nanograting on polarized white light, the readout of laser-written patterns with specific polarization directions can be achieved, and the polarization state resolution can be obtained.

[0051] Please refer to the effect of this embodiment. Figure 10 Each letter in the characters "#Advanced materials#" is written using a different laser polarization state, from left to right: 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 180°. The polarization direction of the polarizer is changed at 10° intervals, and the pattern is observed to change in brightness in 90° cycles under an orthogonal polarization analyzer. Laser polarization states parallel or perpendicular to the polarizer's polarization direction are completely filtered out; the pattern is clearly visible when the laser polarization state forms a 10° angle with the polarizer's polarization direction, achieving 9 polarization states and a 10° angular resolution. The pattern is written using 0.5 μm × 0.5 μm pixels, achieving a 0.5 μm spatial resolution. Furthermore, in conjunction with a reference... Figure 7 Three different colors are written using three different laser wavelengths, thus enabling the recording of 3×9 states and achieving ultra-high density optical storage.

[0052] This invention utilizes laser-induced nanogratings to fabricate super-resolution patterns. By adjusting the laser wavelength, power, and polarization direction to alter the reshaping intensity of nanoparticles and the orientation of the nanograting, two methods are proposed to regulate the polarization state of illuminating white light, achieving sensitive polarization sensing and obtaining high-resolution, high-saturation colors with a spatial resolution of 0.5 micrometers. The formed nanogratings have a polarization-regulating effect on reflected light. Utilizing the polarization-preserving and rotational properties of the nanogratings for linearly polarized white light, laser polarization states with an angular resolution of 10° can be identified within pixels with a spatial resolution of 0.5 micrometers, achieving ultra-high-density optical storage. Compared to existing SOI (Silicon-On-Insulator) etching processes, the method described in this application is simpler and does not require complex processes.

[0053] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A laser direct-writing device for imprinting nanogratings using laser polarization states, characterized in that, The sample includes a nanograting imprint using laser polarization state, as well as a femtosecond laser system, a laser polarization adjustment device, a shutter, a laser focusing device, a micro-nano displacement stage, and a PC with a laser direct writing control program installed. The sample, from bottom to top, comprises a substrate, a metal thin film layer, a dielectric isolation layer, and a metal nano island layer. The dielectric isolation layer is an organic thin film, specifically PMMA. The sample is placed on the micro-nano displacement stage, with the metal nano islands of the sample facing the objective lens aperture of the laser focusing device; The femtosecond laser system outputs femtosecond pulse mode-locked laser, and the laser polarization adjustment device is used to generate different polarization states of the femtosecond pulse mode-locked laser. The polarized light with different polarization states is coupled through the shutter and enters the objective lens of the laser focusing device, and is focused on the surface of the metal nano-island layer. The laser acts on the metal nano-island layer of the sample, and the high energy of the femtosecond pulse mode-locked laser is used to reshape the metal nano-islands into metal nanoparticles, which are arranged in a regular manner to form a nanograting structure, thereby realizing nanoscale imprinting. The nanograting structure is composed of metal nanoparticles reshaped by femtosecond lasers and arranged in a specific orientation. The nanograting structure achieves super-resolution display with optical diffraction limit on pixels of 0.5 micrometers × 0.5 micrometers; The nanograting structure has the functions of maintaining and rotating the polarization angle of the incident light, and can identify the laser polarization state with an angular resolution of 10° in a pixel with a spatial resolution of 0.5 micrometers, thereby realizing ultra-high density optical storage. The laser direct writing control program controls the movement of the micro-nano displacement stage, so that the laser acts on the set area. The laser direct writing control program controls the opening and closing of the shutter, and the shutter controls the on and off of the laser, realizing direct writing of single pixels and non-contiguous areas. The laser polarization adjustment device includes a half glass plate and a quarter glass plate. The femtosecond pulse mode-locked laser passes through the half glass plate and the quarter glass plate in sequence. By rotating the two glass plates, different combinations are obtained, and polarized light with different polarization states can be generated. The laser direct writing device splits the binary image to be imprinted into colors, imports the split images into the laser direct writing control program, sets a set of parameters for laser wavelength, laser power, and laser polarization direction for each split image according to different colors, and then the laser direct writing control program links the opening and closing of the shutter and the movement of the micro-nano displacement stage to complete the imprinting of the pattern on the sample.

2. The laser direct writing device for realizing nanograting imprinting using laser polarization state according to claim 1, characterized in that, The substrate provides support and is made of a rigid, flat material such as glass or silicon wafer. The metal thin film layer is thicker than 100 nm and is made of gold, silver, platinum, or aluminum, deposited on the substrate by vapor deposition or ion sputtering. The flexible material of the dielectric isolation layer is an organic thin film, including PMMA, PVP, or PVA, and is prepared by using a spin coater on the metal thin film layer. Different film thicknesses are achieved by controlling the spin coat speed and time. The metal nano-island layer is prepared by particle sputtering and is made of gold, silver, platinum, or aluminum. The size of the metal nanoparticles on the dielectric isolation layer is controlled by adjusting the sputtering time and current.

3. The laser direct-write device for realizing nanograting imprinting using laser polarization state according to claim 1, characterized in that, By changing the wavelength of the femtosecond pulse mode-locked laser, the intensity of the reshaping and imprinting of the metal nanoislands varies with the wavelength of the laser, resulting in different morphologies and thus controlling the pattern to present different colors. By changing the power of the femtosecond pulse mode-locked laser, the reshaping and imprinting of metal nanoislands by different power lasers can be made to be different, resulting in different morphologies, thereby controlling the pattern to present different colors. By changing the polarization state of the femtosecond pulse mode-locked laser, the orientation and arrangement of the metal nanoparticles reshaped by lasers with different polarization directions are different, thereby controlling the pattern to present different colors.

4. The laser direct writing device for realizing nanograting imprinting using laser polarization state according to claim 1, characterized in that, The resolution can be adjusted by setting the step size of the micro / nano displacement stage to control the pixel size.

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