Refractive index driven hydrogenated amorphous silicon and silicon dioxide combined color filter

Abstract

The invention discloses a refractive index driven hydrogenated amorphous silicon and silicon dioxide combined color filter, and relates to the technical field of micro-nano photoelectric integrated optical devices. A plurality of adjustable structure units are periodically arranged on an XOY plane to form the adjustable structure, and each adjustable structure unit is of a three-layer structure and sequentially comprises an aluminum substrate layer, a SiO2 cylindrical layer and an a-Si: H cylindrical layer from bottom to top. According to the invention, only the three-layer structure of the aluminum substrate layer, the SiO2 cylindrical layer and the a-Si: H cylindrical layer is adopted, and only the cylindrical structure and the cuboid structure are adopted, so that the structure is simple and easy to process and manufacture; the generated color can be tuned by adjusting the thickness of the substrate, the lattice period and the distance between the cylinder and the lattice boundary, and the tuning mode is simple; various subtractive structural colors can be generated within the environment refractive index range of 1.0-2.0; the device is not influenced by the polarization condition of a light source, and can still generate stable colors in a polarization angle range of 0-90 degrees; the method has obvious application potential in the fields of dynamic color encryption, anti-counterfeiting technology and multifunctional dynamic display.

Description

Technical Field

[0001] The refractive-index-driven hydrogenated amorphous silicon and silicon dioxide combined color filter of the present invention relates to the technical field of micro-nano optoelectronic integrated optical devices. Background Art

[0002] Color plays a crucial role in our perception and recognition of the surrounding environment. As a visual information carrier, color not only exists widely in nature, but also plays an irreplaceable role in many fields such as optical display, anti-counterfeiting technology, biosensing, and environmental perception. With the rapid development of nanotechnology and micro-nano manufacturing technology, metasurface structural color, as a new color generation mechanism, has received extensive attention due to its unique optical properties and high tunability.

[0003] In recent years, various innovative metasurface structural color designs have been proposed. Metal-dielectric structures and multi-material combination designs have been widely explored to enhance the flexibility of color regulation and color saturation. Most of the existing metasurface designs rely on fine-tuning of structural parameters to regulate color, but how to ensure the tunability of color regulation under different environmental conditions, especially under the change of environmental refractive index, remains a difficult problem. Although these designs have improved in terms of regulation range and flexibility, there are still certain limitations in adapting to the change of environmental refractive index and suppressing the influence of polarization angle. At the same time, due to the narrow color gamut of the generated subtractive colors, the generated colors often lack sufficient saturation and richness, which limits their expressiveness and usability in practical applications. Summary of the Invention

[0004] To solve the above problems, the present invention proposes a refractive-index-driven hydrogenated amorphous silicon and silicon dioxide combined color filter, which can tune the generated color by adjusting the substrate thickness, lattice period, and the distance between the cylinder and the lattice boundary, and the tuning method is simple; a variety of subtractive structural colors can be generated within the range of environmental refractive index from 1.0 to 2.0; it is not affected by the polarization of the light source and can still produce stable colors within the polarization angle range of 0° to 90°; it has significant application potential in the fields of dynamic color encryption, anti-counterfeiting technology, and multifunctional dynamic display.

[0005] The object of the present invention is achieved as follows:

[0006] The refractive-index-driven hydrogenated amorphous silicon and silicon dioxide combined color filter is composed of a plurality of adjustable structural units arranged periodically in the XOY plane. Each of the adjustable structural units is composed of three layers, which are an aluminum-based bottom layer, a SiO 2 cylinder layer, and an a-Si:H cylinder layer from bottom to top;

[0007] In an adjustable unit, an aluminum-based bottom layer and SiO are defined. 2 The relative positions of the cylindrical layer and the a-Si:H cylindrical layer are as follows: The plane where the aluminum-based bottom layer is located is the XOY plane, that is, the horizontal plane. The center position of the aluminum-based bottom layer coincides with the origin of coordinates. Two pairs of opposite sides of the aluminum-based bottom layer are respectively parallel to the X-axis and the Y-axis. The SiO 2 cylindrical layer and the a-Si:H cylindrical layer are cylinders with the same volume and are stacked together from bottom to top. The SiO 2 The center positions of the cylindrical layer and the a-Si:H cylindrical layer both coincide with the origin of coordinates.

[0008] When the incident light is incident from the negative direction of the Z-axis, the polarization angle is defined as the angle between the polarization state of the incident light and the X-axis.

[0009] For the above refractive index-driven hydrogenated amorphous silicon and silica combined color filter, in an adjustable unit, the projection shape of the aluminum-based bottom layer on the XOY plane is a square, the substrate thickness is H2, the lattice period is P, and the SiO 2 The diameters of the cylinders in the cylindrical layer and the a-Si:H cylindrical layer are D, and the height is H1; the distance between the cylinder and the lattice boundary is g, and P = D + 2g.

[0010] H1 is fixed at 20 nm, the range of P is 260 nm to 420 nm, the range of H2 is 10 nm to 70 nm, the range of g is 40 nm to 80 nm, The range is 0° to 90°, and the refractive index range is 1.0 to 2.0.

[0011] The beneficial effects of the refractive index-driven hydrogenated amorphous silicon and silica combined color filter of the present invention are that it has significant application potential in the fields of dynamic color encryption, anti-counterfeiting technology, and multifunctional dynamic display, specifically reflected in:

[0012] First, there are only three-layer structures of the aluminum-based bottom layer, the SiO 2 cylindrical layer and the a-Si:H cylindrical layer, and there are only two structures of cylinders and cuboids. The structure is simple and easy to process and manufacture.

[0013] Second, by adjusting the substrate thickness H2, the lattice period P, and the distance g between the cylinder and the lattice boundary, the generated color can be tuned, and the tuning method is simple.

[0014] Third, a variety of subtractive structural colors can be generated within the range of the environmental refractive index of 1.0 to 2.0.

[0015] Fourth, it is not affected by the polarization of the light source and can still produce stable colors within the polarization angle range of 0° to 90°. Brief Description of the Drawings

[0016] Figure 1 Schematic three-dimensional structure diagram of the refractive index-driven hydrogenated amorphous silicon and silica combined color filter of the present invention.

[0017] Figure 2 Schematic three-dimensional structure diagram of a single adjustable structural unit.

[0018] Figure 3 Schematic diagram of the relative positions of a single adjustable structural unit.

[0019] Figure 4 Screenshot of the simulation software interface of the present invention.

[0020] Figure 5 Reflection spectral line diagram corresponding to adjusting the thickness H2 of the aluminum substrate while fixing g = 50 nm and P = 340 nm.

[0021] Figure 6 For Figure 5 CIE 1931 chromaticity diagram corresponding to the spectral line.

[0022] Figure 7 CIE 1931 chromaticity diagram corresponding to 45 structural colors generated by simultaneously adjusting g and P.

[0023] Figure 8 Reflection spectral line diagram corresponding to increasing P from 260 nm to 420 nm while fixing g = 50 nm.

[0024] Figure 9 For Figure 8 CIE 1931 chromaticity diagram corresponding to the spectral line.

[0025] Figure 10 CIE 1931 chromaticity diagram corresponding to 54 structural colors generated at different Ps when the environmental refractive index increases from 1.0 to 2.0 while fixing g = 50 nm.

[0026] Figure 11 Reflection curve diagram corresponding to the change of the polarization angle from 0° to 90°.

[0027] In the figure: 1. Aluminum base bottom layer; 2. SiO 2 Cylindrical layer; 3. a-Si:H cylindrical layer. Specific embodiments

[0028] The following further describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. Specific embodiment one

[0030] The refractive index-driven hydrogenated amorphous silicon and silica combined color filter under this specific embodiment, such as Figure 1As shown, it is composed of multiple adjustable structural units arranged periodically in the XOY plane. Each of the adjustable structural units consists of three layers, which are, from bottom to top, an aluminum-based bottom layer 1, a SiO 2 cylindrical layer 2, and an a-Si:H cylindrical layer 3;

[0031] As Figure 2 shown, in an adjustable unit, the relative positions of the aluminum-based bottom layer 1, the SiO 2 cylindrical layer 2, and the a-Si:H cylindrical layer 3 are defined as follows: the plane where the aluminum-based bottom layer 1 is located is the XOY plane, that is, the horizontal plane. The central position of the aluminum-based bottom layer 1 coincides with the coordinate origin. Two pairs of opposite sides of the aluminum-based bottom layer 1 are respectively parallel to the X-axis and the Y-axis. The SiO 2 cylindrical layer 2 and the a-Si:H cylindrical layer 3 are cylinders with the same volume and are stacked on top of each other from bottom to top. The central positions of the SiO 2 cylindrical layer 2 and the a-Si:H cylindrical layer 3 both coincide with the coordinate origin;

[0032] When the incident light is incident from the negative Z-axis direction, the polarization angle is defined as the angle between the polarization state of the incident light and the X-axis.

[0033] As Figure 3 shown, in an adjustable unit, the projected shape of the aluminum-based bottom layer 1 on the XOY plane is a square. The thickness of the substrate is H2, the lattice period is P, and the diameters of the cylinders in the SiO 2 cylindrical layer 2 and the a-Si:H cylindrical layer 3 are D, and the height is H1; the distance between the cylinder and the lattice boundary is g, and P = D + 2g.

[0034] The refractive-index-driven combined color filter of hydrogenated amorphous silicon and silicon dioxide according to the present invention has only three layers of structure, namely, an aluminum-based bottom layer, a SiO 2 cylindrical layer, and an a-Si:H cylindrical layer, and there are only two structures, namely, a cylinder and a cuboid. The structure is simple and easy to process and manufacture. Specific Embodiment 2

[0036] For the refractive-index-driven combined color filter of hydrogenated amorphous silicon and silicon dioxide under this specific embodiment, on the basis of Specific Embodiment 1, it is further limited that: H1 is fixed at 20 nm, the range of P is 260 nm to 420 nm, the range of H2 is 10 nm to 70 nm, the range of g is 40 nm to 80 nm, the range is 0° to 90°, and the refractive index range is 1.0 to 2.0.

[0037] To verify the optical characteristics and performance of the refractive-index-driven hydrogenated amorphous silicon and silica combined color filter of the present invention, the FDTD-Solutions software was used to analyze the optical characteristics and test the performance of the designed metasurface. The screenshot of the simulation software interface is as shown in Figure 4 During the simulation, periodic boundary conditions along the X-axis and Y-axis were adopted for the simulation region, and it was supplemented by a perfectly matched layer (PML) along the Z-axis.

[0038] The designed color filter forms specific colors by subtractive color mixing through selective absorption and reflection of light. The principle of subtractive color mixing is to subtract one or more monochromatic lights of specific wavelengths from polychromatic light (such as white light), so that the remaining combination of light wavelengths presents a new color. The color characteristic analysis was calculated using MATLAB software. The tristimulus values X, Y, and Z and their corresponding chromaticity coordinates were obtained by processing spectral data, and the color performance of the research object was visually demonstrated on the CIE 1931 chromaticity diagram. This method provides an effective and accurate means for characterizing the color characteristics of materials or structures. Specifically, any color can be represented by tristimulus values, which are matched based on the human eye's perception of the three primary colors of red, green, and blue light, and are calculated by the following integral formula:

[0039]

[0040]

[0041] where and are both standard chromaticity functions of CIE 1931, representing the sensitivity of the human eye to the three primary colors of light of different wavelengths respectively. S(λ) is the spectral distribution of the light source, and R(λ) is the reflectivity of the object. is the normalization factor, and the luminance component Y is defined as 100;

[0042] In addition, for the visual expression of colors, the tristimulus values X, Y, and Z are usually converted into two-dimensional chromaticity coordinates x and y as follows:

[0043]

[0044] The converted x and y are represented in the CIE chromaticity diagram. Specific Embodiment 3

[0046] First, the influence of the thickness of the aluminum substrate on the structural color was studied. Starting from Figure 5It can be seen that the distance g between the fixed cylinder and the lattice boundary is 50 nm and the lattice period P is 340 nm. By adjusting the substrate thickness H2, it is observed that as the thickness of the substrate aluminum increases from 10 nm to 70 nm, the color generated by the metasurface changes. As the substrate thickness increases, the spectral curve first undergoes a blue shift and then a red shift. Figure 6 The corresponding color changes in the CIE chromaticity coordinate system are shown, further verifying the influence of the substrate thickness H2 on the color.

[0047] Secondly, it is also possible to decompose the incident white light into multiple reflected colors by changing the geometric dimensions of the SiO 2 cylinder layer 2 and the a-Si:H cylinder layer 3. Fix the heights H1 of the SiO 2 cylinder layer 2 and the a-Si:H cylinder layer 3 at 20 nm and the substrate thickness H2 at 50 nm, and adjust the lattice period P and the distance g between the cylinder and the lattice boundary to adjust the reflected color. In an air environment, when the lattice period P increases from 260 nm to 420 nm in steps of 20 nm, and at the same time the distance g between the cylinder and the lattice boundary increases from 40 nm to 80 nm in steps of 10 nm, the position coordinate map of the 45 structural colors generated by the combination in the CIE 1931 is as Figure 7 shown.

[0048] Finally, to determine the specific influence and variation trend of the lattice period P on the generated color, the distance g between the cylinder and the lattice boundary is fixed at 50 nm, and the lattice period P is increased from 260 nm to 420 nm in steps of 20 nm. From Figure 8 it can be found that the overall reflected spectrum undergoes a red shift towards the long wavelength direction, indicating that as the period increases, the scattering and interference characteristics of the structure for light change. Figure 9 It shows the change of the corresponding color in the CIE 1931 color space. The change of the spectrum directly leads to the migration of the color in the CIE 1931 chromaticity diagram, and the color points gradually move from the short wavelength region (such as blue-violet) to the long wavelength region (such as orange and red).

[0049] Through the above experiments, it can be seen that by adjusting the substrate thickness H2, the lattice period P, and the distance g between the cylinder and the lattice boundary, the generated color can be tuned, and the tuning method is simple. Specific Embodiment Four

[0051] The distance g between the fixed cylinder and the lattice boundary is 50 nm. The dynamic changes of colors under different lattice periods P were studied when the environmental refractive index increased from 1.0 to 2.0. When the lattice period P increased from 260 nm to 420 nm with a step of 20 nm and the environmental refractive index increased from 1.0 to 2.0 with a step of 0.2, 54 structural colors generated by the combination were tested. The position coordinate diagram in CIE 1931 is as shown in Figure 10 shown.

[0052] From the above experiments, it can be seen that a variety of subtractive structural colors can be generated within the range of the environmental refractive index from 1.0 to 2.0. Specific Embodiment Five

[0054] The lattice period P was fixed at 340 nm and the distance g between the fixed cylinder and the lattice boundary was fixed at 50 nm. As the polarization angle changed within the range from 0° to 90°, the reflection curve diagram is as shown in Figure 11 shown. It can be seen that the generated colors remained consistent and no obvious color drift or change was shown.

[0055] From the above experiments, it can be seen that the refractive-index-driven color filter composed of hydrogenated amorphous silicon and silicon dioxide of the present invention is not affected by the polarization of the light source and can still generate stable colors within the range of 0° to 90° polarization angle.

Claims

1. A refractive index driven hydrogenated amorphous silicon and silicon dioxide combined color filter, characterized in that: It is composed of a plurality of adjustable structural units arranged periodically in an XOY plane, each of the adjustable structural units is composed of a three-layer structure, which is, from bottom to top, an aluminum base layer (1), a SiO2 cylindrical layer (2) and an a-Si:H cylindrical layer (3); In an adjustable unit, the relative positions of the aluminum base layer (1), the SiO2 cylindrical layer (2), and the a-Si:H cylindrical layer (3) are defined as follows: the plane where the aluminum base layer (1) is located is the XOY plane, that is, a horizontal plane, the center position of the aluminum base layer (1) coincides with the origin of the coordinate system, the two sets of opposite sides of the aluminum base layer (1) are parallel to the X-axis and the Y-axis, respectively, the SiO2 cylindrical layer (2) and the a-Si:H cylindrical layer (3) are cylinders of the same volume, stacked together from bottom to top, and the center positions of the SiO2 cylindrical layer (2) and the a-Si:H cylindrical layer (3) both coincide with the origin of the coordinate system; When the incident light is incident from the negative direction of the Z axis, the polarization angle φ is defined as the angle between the polarization state of the incident light and the X axis.

2. The refractive index driven hydrogenated amorphous silicon and silicon dioxide combined color filter according to claim 1, characterized in that: In an adjustable unit, the projection shape of the aluminum base layer (1) onto the XOY plane is a square, the base thickness is H2, the lattice period is P, the diameter of the cylinder in the SiO2 cylindrical layer (2) and the a-Si:H cylindrical layer (3) is D, and the height is H1; the distance between the cylinder and the lattice boundary is g, and P=D+2g.

3. The refractive index driven hydrogenated amorphous silicon and silicon dioxide combined color filter according to claim 1, characterized in that: H1 is fixed at 20nm, P ranges from 260nm to 420nm, H2 ranges from 10nm to 70nm, g ranges from 40nm to 80nm, φ ranges from 0° to 90°, and the refractive index ranges from 1.0 to 2.0.

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