阅读说明：本技术 基于选择性吸收与辐射纳米结构的光波段多功能隐身材料 (Optical band multifunctional stealth material based on selective absorption and radiation nano structure ) 是由 *** 潘美妍 黄沄 仇旻 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种基于选择性吸收与辐射纳米结构的光波段多功能隐身材料,包括衬底、设置在衬底表面的激光隐身层、设置在激光隐身层表面的红外宽谱损耗性介质膜层以及设置在最外层的可见光膜层,其满足：对10.6μm波段的激光波的吸收率在0.9以上；对3-5μm以及8-14μm波段的红外光吸收率低于0.3；对5-8μm波段内的红外光的吸收率为0.7～0.9。本发明利用激光隐身层实现激光隐身的目的；利用红外宽谱损耗性介质膜层的干涉实现光谱选择性辐射和高效的散热窗口；利用可见光膜层的干涉实现可见光波段的选择性反射与吸收,通过设置不同厚度改变隐身材料的颜色从而实现可见光的迷彩隐身。(The invention discloses an optical band multifunctional stealth material based on a selective absorption and radiation nanostructure, which comprises a substrate, a laser stealth layer arranged on the surface of the substrate, an infrared wide-spectrum lossy medium film layer arranged on the surface of the laser stealth layer and a visible light film layer arranged on the outermost layer, and meets the following requirements: the absorptivity of the laser wave with the wave band of 10.6 mu m is above 0.9; the absorption rate of infrared light in the wave bands of 3-5 mu m and 8-14 mu m is lower than 0.3; the absorptivity of the infrared light in a wave band of 5-8 mu m is 0.7-0.9. The invention realizes the purpose of laser stealth by utilizing the laser stealth layer; the interference of the infrared wide-spectrum lossy dielectric film layer is utilized to realize spectrum selective radiation and a high-efficiency heat dissipation window; the interference of the visible light film layer is utilized to realize the selective reflection and absorption of the visible light wave band, and the color of the stealth material is changed by setting different thicknesses so as to realize the camouflage stealth of the visible light.)

1. The utility model provides a multi-functional stealthy material of optical band based on selective absorption and radiation nanostructure which characterized in that, includes the substrate, sets up the laser stealthy layer on the surface of the substrate, sets up the infrared wide-spectrum lossy dielectric film layer and the setting in outermost visible light rete on the surface of laser stealthy layer, and it satisfies:

the absorptivity of the laser wave with the wave band of 10.6 mu m is above 0.9;

the absorption rate of infrared light in the wave bands of 3-5 mu m and 8-14 mu m is lower than 0.3;

the absorptivity of the infrared light in a wave band of 5-8 mu m is 0.7-0.9.

2. The optical band multifunctional stealth material based on selective absorption and radiation nanostructures according to claim 1, wherein the laser stealth layer is a metal layer comprising a two-dimensional rectangular array of metal disks as a unit.

3. The optical band multifunctional stealth material based on selective absorption and radiation nanostructures according to claim 2, wherein the metal is one or more of gold, silver, copper, and aluminum.

4. The optical band multifunctional stealth material based on selective absorption and radiation nanostructures according to claim 2, wherein the metal disks are cylinders with a diameter of 5-6 μm, a height of 0.5-1.5 μm, and an array period of 9.5-10.5 μm.

5. The optical band multifunctional stealth material based on the selective absorption and radiation nanostructure according to any one of claims 1 to 3, wherein the laser stealth layer comprises a metal matrix laid on one side surface of the substrate and the metal disc arranged on the surface of the metal matrix.

6. The optical band multifunctional stealth material based on selective absorption and radiation nanostructures according to claim 5, wherein the thickness of the metal matrix is greater than 100 nm.

7. The optical band multifunctional stealth material based on selective absorption and radiation nanostructures according to claim 1, wherein the infrared broadband lossy medium is required to satisfy: there is absorption in the infrared band of 3-14 μm, i.e. the imaginary part of the refractive index is not zero, wherein the imaginary parts of the refractive indices of 3-5 μm and 8-14 μm are less than 0.1.

8. The optical band multifunctional stealth material based on the selective absorption and radiation nanostructure of claim 7, wherein the infrared wide-spectrum lossy dielectric film is a germanium-antimony-tellurium alloy film with a thickness t₁And refractive index n₁Satisfies 4n₁t₁≈6.5。

9. The optical band multifunctional stealth material based on the selective absorption and radiation nanostructure of claim 1, wherein the visible light film layer satisfies:

band gap E_g>0.41eV；

Higher plasmon resonance frequency omega_p＞1.65×10¹⁰Hz。

10. The optical band multifunctional stealth material based on the selective absorption and radiation nanostructure of claim 9, wherein the visible light film layer is made of one or more of Si, Ge, ZnSe and GaAs and has a thickness of 5-40 nm.

Technical Field

The invention relates to the field of optical band multiple stealth, in particular to an optical band multifunctional stealth material based on a selective absorption and radiation nano structure.

Background

Military detection means of the optical band include visible light detection, infrared detection, laser detection and the like. Correspondingly, camouflage, low-emissivity coatings, laser absorption coatings and other stealth means for avoiding detection are also available. Weaponry and the like can simultaneously face the detection of a plurality of optical bands such as visible light, infrared light, laser light and the like on a battlefield, and the use of stealth materials resisting a single frequency band is far from sufficient. The research of the multifunctional stealth material, namely the multiband compatible stealth material, is one of the development directions of the military stealth material technology in the future.

The stealth of the all-optical band needs to integrate the color camouflage of the visible band, the low emissivity of the middle infrared band and the high absorption of the laser wavelength, and is essentially selective reflection, absorption, radiation and the like of the spectrum, and nano materials such as a nano film system structure, a surface nano structure and the like are important means for realizing the spectrum selectivity. At present, researchers realize the compatibility of laser stealth and infrared stealth through a nano film system structure (CN103293582A), but visible light stealth is not taken into consideration. In addition, the stealth effect of the film-based structure depends on a large number of film layers (at least greater than 5) and is very sensitive to the variation of the thickness of each layer, and some challenges are faced in process implementation. In the aspect of surface nano structures, researchers propose a selective radiation infrared stealth structure (CN106767168A), which utilizes metamaterials of composite-size structural units to reduce the radiation intensity of an infrared detection frequency band from two aspects of low radiance of an atmospheric window and high radiation refrigeration of a non-atmospheric window wave band. However, this structure only considers a single stealth approach for infrared camera detection.

At present, no nano material for simultaneously realizing visible light camouflage, infrared stealth and laser stealth is reported.

Disclosure of Invention

The invention aims to overcome the defects of the existing optical band multi-stealth nano material, provides an optical band multi-functional stealth material based on a selective absorption and radiation nano structure, and realizes a stealth technology compatible with visible light, infrared and laser through absorption and radiation spectrum design.

The utility model provides a multi-functional stealthy material of optical band based on selective absorption and radiation nanostructure, includes the substrate, sets up the laser stealthy layer on the substrate surface, sets up the infrared wide-spectrum lossy dielectric film layer and the setting in outermost visible light rete at laser stealthy layer surface, and it satisfies:

the absorptivity of the laser wave with the wave band of 10.6 mu m is above 0.9;

the absorption rate of infrared light in the wave bands of 3-5 mu m and 8-14 mu m is lower than 0.3;

the absorptivity of the infrared light in a wave band of 5-8 mu m is 0.7-0.9.

For substrates, which are primarily used to achieve support of the film layer, a supportive object, i.e. a solid material, may be chosen. Preferably, the substrate is a silicon wafer.

Preferably, the laser stealth layer is a metal layer including a two-dimensional rectangular array with metal disks as units. The grating resonance mode of the metal disc rectangular array is utilized to realize high absorption (higher than 0.9) of normal incidence laser waves of 10.6 mu m, and the aim of laser stealth is fulfilled.

Preferably, the metal is one or more of gold, silver, copper and aluminum. Further preferably gold.

Preferably, the metal disc is a cylinder structure with a diameter of 5-6 μm, a height of 0.5-1.5 μm and an array period of 9.5-10.5 μm.

Preferably, the laser stealth layer (or the metal layer) comprises a metal base body laid on one side surface of the substrate and the metal disc arranged on the surface of the metal base body. The thickness of the metal matrix is more than 100nm, for example, 200-1000 nm.

Preferably, the infrared broad spectrum lossy medium needs to satisfy: there is absorption in the infrared band of 3-14 μm, i.e. the imaginary part of the refractive index is not zero, wherein the imaginary parts of the refractive indices of 3-5 μm and 8-14 μm are less than 0.1. The spectrum selective radiation is realized by utilizing the interference in an infrared wide-spectrum lossy medium (such as crystalline germanium antimony tellurium alloy with infrared wide-spectrum lossy), the average radiance of two middle infrared atmospheric windows (3-5 microns and 8-14 microns) is lower than 0.3, and the radiance in a 5-8 micron waveband outside the atmospheric windows is about 0.8, so that the infrared stealth is met, and a high-efficiency heat dissipation window is provided for a target.

Preferably, the infrared wide-spectrum lossy dielectric film layer is a germanium-antimony-tellurium alloy film with a thickness t₁And refractive index n₁Satisfies 4n₁t₁6.5. Preferably, the germanium antimony tellurium alloy film is crystalline germanium antimony tellurium with wide infrared spectrum loss factor and has the thickness t₁0.25 μm. At a wavelength of 6.5 μm, its refractive index n₁And ≈ 6.26+0.55i (i is an imaginary unit), satisfying the antireflection film condition: 4n of₁t₁≈6.5μm。

The invention realizes the selective reflection and absorption of visible light wave bands by utilizing the interference in the silicon film, and changes the color of the stealth material by setting different thicknesses so as to realize the camouflage and stealth of visible light. Preferably, the visible film layer satisfies:

band gap E_g>0.41eV；

Higher plasmon resonance frequency omega_p＞1.65×10¹⁰Hz。

Preferably, the visible light film layer is made of one or more of Si, Ge, ZnSe and GaAs, and the thickness of the visible light film layer is 5-40 nm. Preferably, the silicon thin film is amorphous silicon or crystalline silicon, and the thickness and color of the silicon nano film correspond to the following relationship: yellow: about 8 nm; blue color: about 20 nm; green: 30 nm.

The invention adopts the cylindrical metal periodic array, and realizes the independence of the absorption polarity of 10.6 mu m. The polarity independence of the absorption of 5-8 mu m wave band is realized by utilizing the infrared wide-spectrum lossy dielectric film layer.

As a specific embodiment, the optical band multifunctional stealth material based on the selective absorption and radiation nanostructure comprises a substrate, a two-dimensional rectangular array taking a metal disc as a unit, a germanium-antimony-tellurium alloy film and a silicon film from bottom to top.

In the present invention, the light wave is mainly incident at a normal angle, but in the case of oblique incidence, the 10.6 μm laser light is not absorbed by the stealth material of the present invention, but is reflected in a direction completely away from the laser detector, and in the case of oblique incidence, the absorption of the 10.6 μm laser light is not necessary, that is, in the case of oblique incidence, the present invention can realize the stealth of the light wave.

The invention has the beneficial effects that:

(1) the invention realizes high absorption (higher than 0.9) of normal incidence 10.6 mu m laser wave by using the grating resonance mode of the metal disc rectangular array, thereby achieving the aim of laser stealth;

(2) the invention realizes spectrum selective radiation by utilizing the interference in the crystalline germanium antimony tellurium alloy thin film with wide spectrum loss, the average radiance of two middle infrared atmospheric windows (3-5 μm and 8-14 μm) is lower than 0.3, and the radiance in a 5-8 μm wave band outside the atmospheric windows is about 0.8, thereby satisfying the infrared stealth and providing a high-efficiency heat dissipation window for a target;

(3) the invention realizes the selective reflection and absorption of visible light wave bands by utilizing the interference in the silicon film, and changes the color of the stealth material by different thicknesses so as to realize the camouflage and stealth of visible light;

(4) the optical band multifunctional stealth material based on the selective absorption and radiation nano structure has the advantages that the polarization angle is gradually increased from 0 to 90 degrees, the frequency and the height of a radiation peak are basically kept unchanged, and the heat radiation of the structure is polarization-independent;

(5) the light band multifunctional stealth material based on the selective absorption and radiation nano structure has the incident angle gradually increased from 0 to 90 degrees, and the original absorption peak at 10.6 mu m generates red shift. In the case of oblique incidence, the 10.6 μm laser light, although not absorbed by the stealth material of the present invention, is reflected in a direction completely away from the laser detector, so that absorption of the 10.6 μm laser light in the case of oblique incidence is not necessary.

Drawings

Fig. 1 is a schematic structural diagram of an optical band multifunctional stealth material based on a selective absorption and radiation nanostructure according to embodiment 1 of the present invention;

fig. 2 is an optical microscope image of a structure of a light band multifunctional stealth material based on selective absorption and radiation nanostructures provided in embodiment 1 of the present invention;

fig. 3 is an infrared absorption spectrum of visible light of the optical band multifunctional stealth material based on the selective absorption and radiation nanostructure provided in example 1 of the present invention;

fig. 4 is a quantitative relationship between the true temperature and the camouflage temperature of the optical band multifunctional camouflage material based on the selective absorption and radiation nanostructure, provided in embodiment 1 of the present invention;

fig. 5 is a graph of an infrared stealth effect of an optical band multifunctional stealth material based on selective absorption and radiation nanostructures provided in embodiment 1 of the present invention;

fig. 6 is a temperature comparison of the optical band multifunctional stealth material based on selective absorption and radiation nanostructures provided in example 1 of the present invention and a conventional low-emissivity stealth coating under the same heating power.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. But the embodiments of the present invention are not limited thereto.