One-dimensional photonic crystal thin film with wide spectral selectivity and preparation method of one-dimensional photonic crystal thin film

Abstract

The invention provides a broad-spectrum selective one-dimensional photonic crystal film and a preparation method thereof, and relates to the technical field of aerospace infrared stealth. The film comprises a visible light regulation and control layer, a short-wave infrared regulation and control layer, a long-wave infrared regulation and control layer and an absorption enhancing layer from top to bottom, the visible light regulation and control layer comprises n1 first structural units, and each first structural unit is composed of a silicon dioxide material layer and a zinc telluride material layer from top to bottom; the short-wave infrared regulation and control layer comprises n2 second structural units, and each second structural unit is composed of a silicon dioxide material layer and a tellurium material layer from top to bottom; the long-wave infrared regulation and control layer comprises n3 third structural units, and each third structural unit is composed of a silicon dioxide material layer and a cadmium selenide material layer from top to bottom; the absorption enhancing layer comprises a material for increasing the absorption rate of medium-long wave band infrared light; and the value range of n1, n2 and n3 is 1-5. The selective emissivity characteristic and the infrared stealth characteristic of the photonic crystal can be further improved.

Description

Technical Field

[0001] The present invention relates to the field of aerospace infrared stealth technology, and in particular to a one-dimensional photonic crystal film with wide spectrum selectivity and a preparation method thereof. Background Art

[0002] With the development and progress of infrared imaging and infrared detection technology, regulating infrared radiation has gradually become a hot research topic. It is crucial in military fields such as military reconnaissance and thermal camouflage, as well as civilian fields such as temperature regulation and infrared sensing.

[0003] To meet the demands of infrared stealth and heat dissipation, which require materials with both low emissivity in one wavelength band and high emissivity in another, a new type of photonic crystal structure has been proposed. Photonic crystals are a type of metamaterial, referring to materials with a periodic spatial distribution of dielectric constants (or refractive indices) that exhibit a photonic bandgap. One-dimensional photonic crystals are a special type of photonic crystal with unique structures and properties, resulting in a wide range of applications. Compared to metasurface structures, which can also manipulate spectral radiation, one-dimensional photonic crystal films offer greater potential for practical applications in stealth and camouflage due to their large-scale and easily processable properties. By carefully designing the structural parameters of photonic crystals (such as the period size, material type, and thickness within the periodic structure), the position and width of the photonic bandgap and passband can be precisely controlled, allowing the artificial fabrication of photonic crystals with specific photonic bandgaps.

[0004] To achieve infrared stealth while simultaneously satisfying low emissivity in one wavelength band and high emissivity in another, many researchers have made significant contributions and explored various technical approaches. For example, Zhang et al. fabricated a Ge / ZnS one-dimensional photonic crystal. This heterojunction photonic crystal structure exhibits an average emissivity as low as 0.046 in the 3.0-5.0μm band, 0.19 in the 8.0-14.0μm band, and 0.579 in the 5.0-8.0μm band, demonstrating both selective emissivity and infrared stealth properties. Photonic crystals also exhibit excellent selective properties in the visible light band. In fact, the color and gradient patterns of butterfly wings, as well as the metallic sheen of some beetle shells, are precisely due to the structure of photonic crystals. However, the selective emissivity and infrared stealth properties of photonic crystals still require further improvement. Summary of the Invention

[0005] The embodiment of the present invention provides a one-dimensional photonic crystal film with wide spectrum selectivity and a preparation method thereof, so as to solve the problem that the selective emissivity characteristics and infrared stealth characteristics of photonic crystals need to be further improved.

[0006] In a first aspect, an embodiment of the present invention provides a one-dimensional photonic crystal film with wide spectral selectivity, comprising: from top to bottom: a visible light control layer, a short-wave infrared control layer, a long-wave infrared control layer, and an absorption enhancement layer;

[0007] The visible light regulation layer includes n1 first structural units, each of which is composed of a silicon dioxide material layer and a zinc telluride material layer from top to bottom;

[0008] The short-wave infrared regulation layer includes n2 second structural units, each of which is composed of a silicon dioxide material layer and a tellurium material layer from top to bottom;

[0009] The long-wave infrared regulation layer includes n3 third structural units, each of which is composed of a silicon dioxide material layer and a cadmium selenide material layer from top to bottom;

[0010] The absorption-enhancing layer includes a material that increases the absorption rate of infrared light in the medium and long wavelength bands;

[0011] The value range of n1, n2 and n3 is 1 to 5.

[0012] In a possible implementation, in the visible light regulating layer:

[0013] The thickness of the zinc telluride material layer is determined according to the refractive index of the zinc telluride material and the central wavelength of the reflection spectrum corresponding to the visible light regulation layer;

[0014] The thickness of the silicon dioxide material layer is determined according to the refractive index of the silicon dioxide material and the central wavelength of the reflection spectrum corresponding to the visible light regulating layer.

[0015] In a possible implementation, in the long-wave infrared regulation layer:

[0016] The thickness of the cadmium selenide material layer is determined according to the refractive index of the cadmium selenide material and the central wavelength of the reflection spectrum corresponding to the long-wave infrared regulation layer;

[0017] The thickness of the silicon dioxide material layer is determined according to the refractive index of the silicon dioxide material and the central wavelength of the reflection spectrum corresponding to the long-wave infrared regulation layer.

[0018] In a possible implementation, in the short-wave infrared regulation layer:

[0019] The tellurium material layer has a thickness ranging from 10 to 100 nm;

[0020] The thickness of the silicon dioxide material layer ranges from 50 to 300 nm.

[0021] In a possible implementation, the material of the absorption enhancement layer is carbon.

[0022] In a possible implementation, the thickness of the absorption enhancement layer ranges from 0.1 to 5 μm.

[0023] In a second aspect, an embodiment of the present invention provides a method for preparing a one-dimensional photonic crystal film with wide spectral selectivity, comprising:

[0024] preparing a thin film substrate, and cleaning and drying the thin film substrate to obtain a pure thin film substrate;

[0025] Using magnetron sputtering technology to plate a material with a first thickness that increases the absorption rate of mid- and long-wave infrared light on the pure film substrate to form an absorption-enhancing layer;

[0026] Using magnetron sputtering technology to alternately plate cadmium selenide material layers and silicon dioxide material layers on the absorption enhancement layer, plating n3 cycles to form a long-wave infrared regulation layer;

[0027] Using magnetron sputtering technology to alternately plate tellurium material layers and silicon dioxide material layers on the long-wave infrared regulation layer for n2 cycles to form a short-wave infrared regulation layer;

[0028] A zinc telluride material layer and a silicon dioxide material layer are alternately plated on the short-wave infrared control layer using magnetron sputtering technology for n1 cycles to form a visible light control layer, thereby obtaining a wide spectrum selective one-dimensional photonic crystal film.

[0029] In an embodiment of the present invention, a wide-spectrum-selective one-dimensional photonic crystal film is formed by a visible light regulation layer, a short-wave infrared regulation layer, a long-wave infrared regulation layer and an absorption-enhancing layer from top to bottom, and the visible light regulation layer includes n1 first structural units, each of which is composed of a silicon dioxide material layer and a zinc telluride material layer from top to bottom; the short-wave infrared regulation layer includes n2 second structural units, each of which is composed of a silicon dioxide material layer and a tellurium material layer from top to bottom; the long-wave infrared regulation layer includes n3 third structural units, each of which is composed of a silicon dioxide material layer and a cadmium selenide material layer from top to bottom; the absorption-enhancing layer includes a material that increases the absorption rate of infrared light in the medium and long-wave bands; and the value range of n1, n2, and n3 is 1 to 5. Visible light control layers, short-wave infrared control layers, and long-wave infrared control layers can be used to achieve broadband, wide-angle, and high reflection through the sidebands of photonic crystals. Multiple one-dimensional photonic crystal structures can be combined to achieve the effect of controlling multiple bands. At the same time, the absorption enhancement layer can be used to improve the absorption rate to form the broadband and wide-angle absorption characteristics of the atmospheric transparent window, thereby achieving multi-band compatibility and selective absorption characteristics in specific bands, further improving the selective emissivity characteristics and infrared stealth characteristics of the photonic crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1Schematic diagram of the structure of a one-dimensional photonic crystal film with wide spectral selectivity provided by an embodiment of the present invention;

[0031] Figure 2 Schematic diagram of the infrared emissivity curve of the wide spectral selectivity one-dimensional photonic crystal film provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] With the development and advancement of infrared imaging and detection technologies, regulating infrared radiation has become a hot research topic. It is crucial in military applications such as reconnaissance and thermal camouflage, as well as civilian applications such as temperature regulation and infrared sensing. Due to its unique advantages, infrared detection technology has been applied in a wide range of fields, including target detection, identification, targeting, and guidance, leading to rapid development of infrared technology. Advances in science and technology have led to increasingly complex and precise detectors and image processing processes. Infrared detection technology boasts excellent concealment, strong anti-interference capabilities, all-weather capability, and adaptability, making infrared reconnaissance and guidance systems a serious threat to weaponry and ground-based military installations. Therefore, the research and application of infrared emissivity regulation technology, aimed at reducing target detectability, is urgent.

[0034] The infrared atmospheric window encompasses three wavelength bands: 0.76-1.5μm, 3-5μm, and 8-14μm. Different wavelength bands play an irreplaceable role in infrared information warfare. Objects at different temperatures emit radiation in different infrared wavelength bands. However, in applications such as infrared stealth and heat dissipation, materials often require both low emissivity in one wavelength band and high emissivity in another. For example, in military confrontations, many military equipment and facilities emit infrared radiation due to their inherent temperature, making them easily detectable by enemy infrared detection equipment. For example, ground-based military facilities can effectively be detected by thermal imaging systems in the 8-14μm far-infrared band. To achieve infrared stealth and reduce the probability of enemy detection, materials with low emissivity in this wavelength band are required to reduce the amount of infrared energy radiated by military targets. However, equipment generates significant heat during operation. Failure to dissipate heat promptly can affect performance and even cause failure. This requires the material to have a high emissivity in another atmospheric window band (such as the 3-5μm band) in order to efficiently dissipate heat and cool down to ensure the normal operation of the equipment. Alternatively, in some civilian equipment or places with high requirements for temperature control, such as in the field of electronic equipment, core components such as chips will generate a lot of heat when working. If the heat is not dissipated in time, it will lead to performance degradation and shortened life. At this time, the heat dissipation material needs to have a high emissivity in a specific band to quickly radiate the heat; and for parts such as the outer shell of the equipment, in order to avoid excessive heat dissipation from the internal part of the equipment to the surrounding environment, affecting the overall performance and energy utilization efficiency of the equipment, it is hoped that it will have a low emissivity in certain bands to achieve effective heat management and ensure stable operation of the equipment. There is a certain contradiction between the two. It is difficult for traditional infrared stealth materials to simultaneously meet the two key factors of low emissivity in a certain band and high emissivity in another band.

[0035] On this basis, a new type of photonic crystal structure provides new possibilities for spectral modulation. Photonic crystals are a type of metamaterial, which refers to special materials with a photonic bandgap due to a periodic distribution of dielectric constants (or refractive indices) in space. One-dimensional photonic crystals are a special type of photonic crystal with unique structure and properties, and are widely used in many fields. Compared with metasurface structures that can also perform spectral radiation regulation, one-dimensional photonic crystal films have greater development potential in practical applications such as stealth and camouflage due to their large area and easy processing characteristics. Its structure is usually formed by alternating stacking of two or more materials with different dielectric constants (or refractive indices) in a one-dimensional direction. For example, a common one-dimensional photonic crystal may be composed of a periodic arrangement of layers of high refractive index material and low refractive index material, just like making a thousand-layer pancake, one layer of one material, then another layer, and so on. This periodic structure is a key characteristic that distinguishes it from ordinary materials, causing the material's dielectric constant (or refractive index) to vary periodically. When electromagnetic waves are incident on a one-dimensional photonic crystal, they interact with the periodic structure. According to the Bragg reflection principle, when certain conditions are met, destructive interference occurs, forming a photonic bandgap. Within the photonic bandgap, the photon state density vanishes, meaning that electromagnetic waves within a specific frequency range cannot propagate within it, like a "no-go" barrier for electromagnetic waves. Conversely, within the photonic passband, the photon state density oscillates, leading to transmission resonance in the photonic crystal, allowing electromagnetic waves of specific frequencies to pass smoothly. In some one-dimensional photonic crystals, specific wavelengths of light are strongly reflected, while other wavelengths are transmitted. By carefully designing structural parameters (such as the size of the periodic structure, the type of material, and the thickness), the position and width of the bandgap and passband can be precisely controlled, allowing photonic crystals with specific photonic bandgaps to be artificially fabricated.

[0036] To achieve infrared stealth while simultaneously satisfying low emissivity in one wavelength band and high emissivity in another, many researchers have made significant contributions and explored various technical approaches. For example, Zhang et al. fabricated a Ge / ZnS one-dimensional photonic crystal. This heterojunction photonic crystal structure exhibits an average emissivity as low as 0.046 in the 3.0-5.0μm band, 0.19 in the 8.0-14.0μm band, and 0.579 in the 5.0-8.0μm band, demonstrating both selective emissivity and infrared stealth properties. Photonic crystals also exhibit excellent selective properties in the visible light band. In fact, the color and gradient patterns of butterfly wings, as well as the metallic sheen of some beetle shells, are precisely due to the structure of photonic crystals. However, the selective emissivity and infrared stealth properties of photonic crystals still require further improvement.

[0037] To this end, an embodiment of the present invention provides a one-dimensional photonic crystal film with wide spectral selectivity. Figure 1As shown, the wide spectrum selective one-dimensional photonic crystal film includes: from top to bottom a visible light regulation layer (i.e., the (AB)n structural unit), a short-wave infrared regulation layer (i.e., the (AC)n structural unit), a long-wave infrared regulation layer (i.e., the (AD)n structural unit) and an absorption enhancement layer.

[0038] The visible light regulation layer includes n1 first structural units, and each first structural unit is composed of a silicon dioxide SiO2 material layer (ie, A material layer) and a zinc telluride ZnTe material layer (ie, B material layer) from top to bottom.

[0039] The short-wave infrared regulation layer includes n2 second structural units, and each second structural unit is composed of a silicon dioxide SiO2 material layer (ie, A material layer) and a tellurium Te material layer (ie, C material layer) from top to bottom.

[0040] The long-wave infrared regulation layer includes n3 third structural units, and each third structural unit is composed of a silicon dioxide SiO2 material layer (ie, A material layer) and a cadmium selenide CdSe material layer (ie, D material layer) from top to bottom.

[0041] The absorption-enhancing layer includes a material (such as E material) that increases the absorption rate of mid- and long-wave infrared light.

[0042] The value range of n1, n2, and n3 is 1 to 5.

[0043] Optionally, in the visible light regulation layer:

[0044] The thickness of the zinc telluride material layer can be determined according to the refractive index of the zinc telluride material and the central wavelength of the reflection spectrum corresponding to the visible light regulation layer.

[0045] The thickness of the silicon dioxide material layer can be determined according to the refractive index of the silicon dioxide material and the central wavelength of the reflection spectrum corresponding to the visible light modulation layer.

[0046] In this embodiment, the visible light control layer can be made of materials that do not affect the infrared light absorption rate. The presence of the (AB)n structural unit and the number of periods n1 have little effect on the near-infrared, mid-wave infrared, and long-wave infrared emission properties of the selective absorption film (i.e., the wide-spectrum selective one-dimensional photonic crystal film). For the (AB)n structural unit, the physical thickness of the A material layer and the B material layer can be determined based on the refractive index of the material and the arbitrary reflection center wavelength, respectively. The physical thickness calculation formula is:

[0047]

[0048] Among them, d A Represents the physical thickness of the A material layer, n A is the refractive index of material A, d B Represents the physical thickness of the B material layer, nB is the refractive index of material B, and λ represents the central wavelength of the reflection spectrum. For the (AB)n structural unit, the number of periods n1 can be 1 to 5, and different numbers of periods correspond to different visible light (0.4-1μm) reflectivities. The larger n1 is, the lower the absorption rate of the selective absorption film in the visible light band is. The (AB)n structural unit is composed of a one-dimensional photonic crystal structure by stacking materials A and B with different refractive indices, which can realize the reflection of incident light of a specific wavelength. When the number of periods of the (AB)n structural unit is large (for example, n1 ≥ 3), it has a higher visible light reflectivity and can largely avoid the absorption of sunlight.

[0049] Optionally, in the long-wave infrared control layer:

[0050] The thickness of the cadmium selenide material layer can be determined according to the refractive index of the cadmium selenide material and the central wavelength of the reflection spectrum corresponding to the long-wave infrared regulation layer.

[0051] The thickness of the silicon dioxide material layer can be determined according to the refractive index of the silicon dioxide material and the central wavelength of the reflection spectrum corresponding to the long-wave infrared control layer.

[0052] In this embodiment, the long-wave infrared control layer can select two materials with high and low refractive indices for periodic arrangement to reduce the absorption rate of the long-wave infrared slope section, so that the film structure (that is, a wide-spectrum selective one-dimensional photonic crystal film) selectively absorbs only in the mid-infrared band. For the (AD)n structural unit, the physical thickness of the A material layer and the D material layer is determined in the same process as the physical thickness of the A material layer and the B material layer in the (AB)n structural unit, that is, it is determined according to the refractive index of the material and any reflection center wavelength. For the (AD)n structural unit, the number of periods n3 can also be 1 to 5. The (AD)n structural unit is composed of a one-dimensional photonic crystal structure by stacking materials A and D with different refractive indices, which can realize the reflection of incident light of a specific wavelength.

[0053] Optionally, in the SWIR control layer:

[0054] The thickness of the tellurium material layer ranges from 10 to 200 nm, and the thickness of the silicon dioxide material layer ranges from 50 to 400 nm.

[0055] In this embodiment, the short-wave infrared modulation layer can be made of materials that do not affect the absorption rate of mid- and far-infrared light. The (AC)n structural unit can modulate the spectrum in the near-infrared band. For the (AC)n structural unit, the physical thickness of the A and C material layers can be determined through TFCale software design optimization.

[0056] For example, you can import the optical constants of the material into the TFCale software; then set the environment window, including the reference wavelength, the wavelength range to be calculated, the incident angle, the substrate incident and output media, and the light source; then enter the film layer structure (HL) N , you need to specify H, which is the material with high refractive index, and L, which is the material with low refractive index, and set the thickness of the material and whether it needs to be optimized; then set the optimization target value, that is, determine the absorption rate value corresponding to the specific band as the target for optimization; finally, use the built-in optimization algorithm to perform the film layer structure (HL) N The optimization program changes the film parameters to minimize the evaluation function and ultimately achieve the desired optimal result. For example, after optimization, the physical thickness ranges of magnetron sputtered films of materials A and C are 50-400nm and 10-200nm, respectively.

[0057] Optionally, the material of the absorption enhancement layer may be carbon C, and the thickness of the absorption enhancement layer may be in the range of 0.1 to 5 μm.

[0058] In this embodiment, carbon material is selected as the absorption-enhancing layer. High-absorption graphite (ie, carbon) can increase the absorption rate of the entire band, thereby increasing the absorption rate of the mid- and far-infrared bands, and further increasing the overall absorption rate of the wide-spectrum selective one-dimensional photonic crystal film.

[0059] It should be noted that the absorption-enhancing layer can also be made of materials such as aluminum oxide (AlO3), which can increase the absorption rate of mid- and long-wavelength infrared light. Generally, the thickness required for the AlO3 absorption-enhancing layer is generally in the millimeter range. To enhance the flexibility of the resulting wide-spectrum-selective one-dimensional photonic crystal film, carbon is preferably used as the absorption-enhancing layer.

[0060] For example, the A material layer, the B material layer, the C material layer, the D material layer and the E material layer corresponding to the absorption enhancement layer can all be prepared by magnetron sputtering.

[0061] In this embodiment, the (AB)n structural unit is used to regulate the visible light spectrum, and the (AC)n structural unit is used to regulate the short-wave infrared spectrum. The visible light regulation layer (corresponding to the 0.4-1μm band) and the short-wave infrared regulation layer (corresponding to the 0.76-3μm band) can reduce the absorption rate of the visible light and near-infrared bands. Then, the (AD)n structural unit is used to regulate the long-wave infrared spectrum, and the long-wave infrared regulation layer (corresponding to the 8-14μm band) can reduce the absorption rate of the long-wave infrared band. Finally, the absorption layer is used to increase the absorption rate of the medium-wave infrared band or the mid-to-far infrared band. As a result, in the entire 0.4-14μm band, only the medium-wave infrared band (that is, the 3.5-6μm band) has high absorption, achieving multi-band compatible with the medium-wave infrared selective absorption, and then through the excellent electromagnetic regulation performance of the multi-layer periodic structure, the target's infrared camouflage is achieved. Compared with others, this embodiment can be produced in a large area without photolithography and has selective absorption characteristics.

[0062] An embodiment of the present invention further provides a method for preparing a one-dimensional photonic crystal film with wide spectral selectivity, comprising:

[0063] A thin film substrate is prepared, cleaned and dried to obtain a pure thin film substrate.

[0064] A thin film substrate is prepared, cleaned and dried to obtain a pure thin film substrate.

[0065] A material with a first thickness for increasing the absorption rate of mid- and long-wave infrared light is plated on a pure film substrate using magnetron sputtering technology to form an absorption-enhancing layer.

[0066] The magnetron sputtering technology is used to alternately plate cadmium selenide material layers and silicon dioxide material layers on the absorption enhancement layer, and the plating is performed for n3 cycles to form a long-wave infrared regulation layer.

[0067] The tellurium material layer and the silicon dioxide material layer are alternately plated on the long-wave infrared control layer by magnetron sputtering technology, and the plating is performed for n2 cycles to form a short-wave infrared control layer.

[0068] Magnetron sputtering technology is used to alternately deposit zinc telluride material layers and silicon dioxide material layers on the short-wave infrared control layer for n1 cycles to form a visible light control layer, thereby obtaining a wide spectrum selective one-dimensional photonic crystal film.

[0069] The following example illustrates the preparation process of a one-dimensional photonic crystal film with broad spectral selectivity:

[0070] 1. Prepare a PI film substrate, clean it with acetone, isopropyl alcohol (IPA), and deionized water ultrasonically in sequence, and then dry it to obtain a pure PI film substrate.

[0071] 2. Use magnetron sputtering technology to coat a layer of non-metallic carbon with a thickness of more than 1000nm on the pure PI film substrate, which has a large absorption rate in the medium and long wave infrared bands to form an absorption enhancement layer.

[0072] 3. Use magnetron sputtering to deposit a film on the absorption enhancement layer, first depositing the (AD)n structural unit. Alternately deposit two materials, A and D, where A is SiO2 and D is CdSe. First, deposit a layer of D on the carbon layer, then a layer of A. Repeat this cycle for n3 cycles, with one layer of D followed by another.

[0073] 4. Continue to prepare (AC)n structural units on the plated (AD)n structural units. On the (AD)n structural units, two materials A and C are alternately plated. A is SiO2 and C is Te. First plate a layer of C, then a layer of A. The plating cycle is one layer of C and one layer of A. Repeat the plating cycle for n2 times.

[0074] 5. Continue to prepare the (AB)n structural unit on the plated (AC)n structural unit. On the (AC)n structural unit, alternately plate two materials A and B, where A is SiO2 and B is ZnTe. Plate a layer of B first, then a layer of A. The plating cycle is one layer of B and one layer of A. Repeat the plating cycle for n1 times.

[0075] 6. After the film is deposited, the sample is taken out from the magnetron sputtering device to obtain a one-dimensional photonic crystal film with wide spectral selectivity.

[0076] For example, Figure 2 As shown in the figure, after preparing the wide spectrum selective one-dimensional photonic crystal film, its infrared emissivity curve can be obtained by finite element method simulation. Figure 2 It can be seen that its average absorptivity in the mid-infrared (3.5-6 μm) band is 0.8, the average absorptivity in the visible light (0.4-1 μm) band is 0.17, the average absorptivity in the near-infrared (1-3 μm) band is 0.08, and the average absorptivity in the far-infrared (8-14 μm) band is 0.02. It can be seen that the wide spectral selectivity one-dimensional photonic crystal film prepared according to this embodiment has an overall high average absorptivity in the working band (3.5-6 μm) and a high reflectivity in other bands.

[0077] For example, for the (AB)n structural unit, taking the central wavelength of the corresponding reflection spectrum as 700nm, the refractive index of material A (SiO2) as 1.48, and the refractive index of material B (ZnTe) as 4.3, we can get d A =200nm,d B=55nm, the number of periods n1 can be 1 to 5. For the (AC)n structural unit, taking the number of periods n2 as 3 as an example, after optimization, the thicknesses of the three layers of material A (SiO2) are: 310nm, 320nm, 268nm; the thicknesses of the three layers of material C (Te) are: 120nm, 160nm, 90nm. For the (AD)n structural unit, taking the central wavelength of the corresponding reflection spectrum as 11μm, the refractive index of material A (SiO2) is 1.45, and the refractive index of material D (CdSe) is 3.5 as an example, it can be obtained that d A =1.5μm, d D = 0.7 μm, and the number of periods n3 can be 1 to 5. By adjusting the film thickness of each structural unit, the number of structural unit periods, and the thickness of the absorption-enhancing layer, the absorption spectrum curve of the selective absorption film (i.e., the wide spectrum selective one-dimensional photonic crystal film) can be controlled.

[0078] In an embodiment of the present invention, the sidebands of photonic crystals are used to achieve broadband, wide-angle, and high reflection. Multiple one-dimensional photonic crystal structures are combined to achieve the effect of regulating multiple bands. At the same time, the absorption rate is increased by using the carbon in the absorption layer to form a broadband, wide-angle absorption characteristic of an atmospheric transparent window, thereby achieving multi-band compatibility and selective absorption in specific bands. The multi-band compatible neutralization selective absorption film (i.e., a wide spectrum selective one-dimensional photonic crystal film) proposed in this embodiment has a higher average absorption rate in the working band (3.5-6μm) and a higher reflectivity in other bands compared to previous devices, achieving control of the emissivity of visible light, near-infrared, and mid- and far-infrared on a single surface. With the help of this film, stealth can be achieved in the visible, near-infrared, and far-infrared bands, and heat can be dissipated in the mid-wave infrared band. It is difficult for a single surface to achieve multi-band compatibility and selective absorption in specific bands, achieving better camouflage and stealth functions. Moreover, the proposed multi-band compatible neutralization selective absorption film has a simple structure and can be prepared over a large area without photolithography, thus avoiding complex micro-nano processing technology, which helps to improve preparation efficiency and reduce preparation costs.

[0079] In the above embodiments, the descriptions of each embodiment have their own focus. For parts not described or recorded in detail in one embodiment, please refer to the relevant descriptions of other embodiments. Unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features of different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0080] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A one-dimensional photonic crystal film with broad spectral selectivity, characterized in that: include: From top to bottom, there are the visible light regulation layer, the short-wave infrared regulation layer, the long-wave infrared regulation layer and the absorption enhancement layer; The visible light regulation layer includes n1 first structural units, each of which is composed of a silicon dioxide material layer and a zinc telluride material layer from top to bottom; The short-wave infrared regulation layer includes n2 second structural units, each of which is composed of a silicon dioxide material layer and a tellurium material layer from top to bottom; The long-wave infrared regulation layer includes n3 third structural units, each of which is composed of a silicon dioxide material layer and a cadmium selenide material layer from top to bottom; The absorption-enhancing layer includes a material that increases the absorption rate of infrared light in the medium and long wavelength bands; The value range of n1, n2 and n3 is 1 to 5.

2. The one-dimensional photonic crystal film with wide spectral selectivity according to claim 1, characterized in that: In the visible light regulating layer: The thickness of the zinc telluride material layer is determined according to the refractive index of the zinc telluride material and the central wavelength of the reflection spectrum corresponding to the visible light regulation layer; The thickness of the silicon dioxide material layer is determined according to the refractive index of the silicon dioxide material and the central wavelength of the reflection spectrum corresponding to the visible light regulating layer.

3. The one-dimensional photonic crystal film with wide spectral selectivity according to claim 1, characterized in that: In the long-wave infrared regulation layer: The thickness of the cadmium selenide material layer is determined according to the refractive index of the cadmium selenide material and the central wavelength of the reflection spectrum corresponding to the long-wave infrared regulation layer; The thickness of the silicon dioxide material layer is determined according to the refractive index of the silicon dioxide material and the central wavelength of the reflection spectrum corresponding to the long-wave infrared regulation layer.

4. The one-dimensional photonic crystal film with wide spectral selectivity according to claim 1, characterized in that: In the shortwave infrared regulation layer: The tellurium material layer has a thickness ranging from 10 to 200 nm; The thickness of the silicon dioxide material layer ranges from 50 to 400 nm.

5. The one-dimensional photonic crystal film with wide spectral selectivity according to claim 1, characterized in that: The material of the absorption enhancement layer is carbon.

6. The one-dimensional photonic crystal film with wide spectral selectivity according to claim 5, characterized in that: The thickness of the absorption enhancement layer ranges from 0.1 to 5 μm.

7. A method for preparing a one-dimensional photonic crystal film with wide spectral selectivity, characterized in that: include: preparing a thin film substrate, and cleaning and drying the thin film substrate to obtain a pure thin film substrate; Using magnetron sputtering technology to plate a material with a first thickness that increases the absorption rate of mid- and long-wave infrared light on the pure film substrate to form an absorption-enhancing layer; Using magnetron sputtering technology to alternately plate cadmium selenide material layers and silicon dioxide material layers on the absorption enhancement layer, plating n3 cycles to form a long-wave infrared regulation layer; Using magnetron sputtering technology to alternately plate tellurium material layers and silicon dioxide material layers on the long-wave infrared regulation layer for n2 cycles to form a short-wave infrared regulation layer; A zinc telluride material layer and a silicon dioxide material layer are alternately plated on the short-wave infrared control layer using magnetron sputtering technology for n1 cycles to form a visible light control layer, thereby obtaining a wide spectrum selective one-dimensional photonic crystal film.

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