Infrared scene generation device based on metamaterial thermal radiation

Abstract

The invention discloses an infrared scene generation device based on metamaterial thermal radiation, and relates to the technical field of infrared scene generation. The device is composed of a radiation unit array, each radiation unit is composed of a pixel, an optical fiber probe, a coupler and an output optical fiber, and each pixel is composed of a first broadband metamaterial thermal radiation pixel, a second broadband metamaterial thermal radiation pixel, a tunable linear spectrum metamaterial thermal radiation pixel and a tunable narrow-band metamaterial thermal radiation pixel. The four thermal radiation pixels are respectively connected with the input end of the coupler through the optical fiber probe, and the output optical fiber is connected with the output end of the coupler. The infrared scene with the fine structure spectrum can be more flexibly generated by adopting the metamaterial heat radiation pixels, and the improvement of the target recognition accuracy and the anti-interference characteristic of the infrared imaging guidance system is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of infrared scene generation, and in particular to an infrared scene generation device based on metamaterial thermal radiation. Background Art

[0002] Infrared imaging guidance technology uses infrared cameras to capture and track the energy radiated by the target to achieve homing guidance. It has the advantages of high sensitivity, high precision, high spatial resolution, large dynamic tracking range, large effective range, and strong anti-interference. However, testing and training infrared imaging guidance systems in real scenes are difficult, expensive, long, and have poor repeatability. Infrared imaging guidance semi-physical simulation technology can solve the above problems and realize comprehensive testing and evaluation of guided weapon performance. Among them, infrared scene generation technology is the core technology of infrared imaging guidance semi-physical simulation system, which is used to simulate the light radiation of infrared scenes for imaging systems (such as seekers) to receive.

[0003] Infrared decoys produce high-temperature flames by burning to imitate the light radiation of the protected target to deceive and interfere with the infrared imaging guidance system. The radiation spectrum of infrared decoys and aircraft tail flames is similar. The seeker needs to continuously improve its ability to identify targets and decoys to cope with the development of infrared decoy technology. Multispectral imaging guidance technology can improve the seeker's ability to identify targets and decoys by acquiring and comparing multispectral images of targets and decoys in infrared scenes. The development of multispectral imaging guidance technology has put forward higher requirements for infrared imaging guidance semi-physical simulation technology. Infrared scene generation needs to provide a fine and realistic spectrum to meet simulation requirements.

[0004] Infrared scene generation methods can be divided into two categories: direct radiation type and radiation modulation type. Among them: the direct radiation type infrared scene generation method uses a pixel array to generate infrared radiation, and generates the required infrared scene by controlling the radiation intensity of each pixel, such as a resistor array radiating a continuous spectrum, an infrared light emitting diode array radiating a narrow-band spectrum, and an infrared laser diode array radiating a linear spectrum; the radiation modulation type infrared scene generation method generates the required infrared scene by modulating the spatial intensity of the infrared light source irradiated onto the infrared spatial light modulator, such as each pixel of a digital micromirror device modulates a blackbody light source to generate the required two-dimensional light distribution, and its radiation spectrum is a continuous spectrum.

[0005] Since the 1980s, resistor arrays have dominated the field of infrared scene generation, and three pixel structure devices have been developed: thin film, bridge and suspended film. However, the apparent temperature of resistor arrays is limited to about 700K, and the response speed is low. From 2016 to 2017, Santa Barbara Infrared Company in the United States overcame these shortcomings and developed a resistor array with an apparent temperature of more than 1500K and a frame rate of 500Hz. On the other hand, experimental results have shown that infrared light-emitting diodes have advantages such as an apparent temperature of more than 1000K, fast response speed, and large dynamic range. Infrared light-emitting diode arrays have also been developed in the field of infrared scene generation. In 2016, the University of Delaware and the University of Iowa in the United States developed a 512×512 pixel infrared light-emitting diode array and obtained an apparent temperature of 1350K. In 2019, the University of Delaware and Hockessin Chip Design Systems LLC proposed a modular and scalable infrared light-emitting diode array design method and demonstrated infrared scene generation results. Domestically, from 2016 to 2018, Beijing Institute of Technology studied infrared scene generation methods based on visible light / infrared image conversion films. In 2018, the China Air-to-Air Missile Research Institute designed a multi-spectral target simulation system based on resistor array optical alignment. Harbin Institute of Technology has also carried out a lot of research in the field of infrared scene generation. The inventor used micro-optical beam expansion technology to study the multi-interference optical path infrared scene generation system from 2014 to 2016, and studied the image-side telecentric optical path optical system that suppresses the cold reflection of the resistor array in 2019.

[0006] However, the infrared radiation of the target tail flame and infrared decoy bomb in the infrared scene usually contains continuous spectrum, linear spectrum and narrow-band spectrum. Although the existing infrared scene generation methods at home and abroad can simulate the energy distribution of target and decoy bomb radiation, they are still inconsistent with the target and decoy bomb radiation in terms of spectral fine structure characteristics.

[0007] Metamaterials are a new type of material that emerged in the 21st century. They are a type of artificial material with special properties that does not exist in nature. They have special functions that traditional materials cannot achieve, such as negative refractive index, electromagnetic stealth, anti-Doppler effect, etc. The development and rise of metamaterials has brought new opportunities and hopes for the development of traditional infrared thermal radiation technology, and has become one of the most dynamic research directions in the field of infrared thermal radiation technology. Metamaterial absorbers were first proposed by Boston College and Duke University in the United States in 2008. By adjusting the microstructure of metamaterial absorbers, absorption spectra of different shapes can be obtained. According to Kirchhoff's law of thermal radiation, under thermal equilibrium conditions, the emissivity of a material is equal to the absorptivity. Research work on using heated metamaterial absorbers as metamaterial thermal radiators has also been carried out. In 2015, Arizona State University in the United States and Royal Melbourne Institute of Technology University in Australia jointly studied a metamaterial absorber composed of a two-dimensional titanium grating, a magnesium fluoride dielectric film and a tungsten metal film. The test spectrum of the metamaterial absorber has good stability in the temperature range of 23.5 to 350°C. Since the broadband radiation spectrum of metamaterial thermal radiators has the advantage of wavelength selectivity, the application of metamaterial thermal radiators in thermophotovoltaic systems can improve the energy conversion efficiency of the system. In 2018, the Physical Science Corporation, Sandia National Laboratories and MIT Lincoln Laboratory jointly developed a metamaterial thermal radiator for thermophotovoltaic systems, and verified that the metamaterial thermal radiator heated to 1055°C can achieve a higher thermoelectric conversion efficiency than conventional thermal radiators. In 2019, the Technical University of Hamburg in Germany and its partners jointly studied the high temperature resistance of metamaterial thermal radiators, and experiments proved that the metamaterial thermal radiator they developed can maintain a stable radiation spectrum at an operating temperature of 1400°C. Domestically, the Institute of Optoelectronics Technology of the Chinese Academy of Sciences developed a metamaterial absorber operating in the 200-900nm band in 2018. The test spectrum of the metamaterial absorber after annealing at 600°C is basically consistent with the test spectrum before heating. Zhejiang University developed a dual-band metamaterial thermal radiator in 2018 and tested the spectral characteristics of the metamaterial thermal radiator in the temperature range of 100-203°C. Shanghai Jiao Tong University and its partners jointly developed an all-dielectric metamaterial absorber in 2019. Experimental results show that the spectrum of the metamaterial absorber does not change substantially in the temperature range of 0-100°C. Although research results of metamaterial absorbers and metamaterial thermal radiators with linear spectra and narrowband spectra have been reported, it is difficult to achieve tunability of the spectrum. Harbin Institute of Technology has carried out a lot of research work in the design, processing and testing of metamaterial absorbers. The inventors have conducted in-depth research on the generation and tuning mechanism of linear spectra and narrowband spectra based on guided mode resonance, and developed a tunable linear spectrum metamaterial absorber based on guided mode resonance in 2019. Tuneable narrowband spectrum metamaterial absorbers based on guided mode resonance have also made certain progress.In order to simplify the structure of the broadband metamaterial absorber, the inventors developed a simple double-layer two-dimensional cylindrical array structure broadband metamaterial absorber in 2020.

[0008] In summary, although a lot of research results have been achieved on metamaterial absorbers and metamaterial thermal radiators at home and abroad, their application in infrared scene generation methods is still blank. Summary of the invention

[0009] In order to address the shortcomings of the background technology, the present invention provides an infrared scene generation device based on metamaterial thermal radiation, which uses metamaterial thermal radiation pixels to more flexibly generate infrared scenes with fine structure spectra, which helps to improve the target recognition accuracy and anti-interference characteristics of infrared imaging guidance systems.

[0010] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an infrared scene generation device based on metamaterial thermal radiation, composed of an array of N radiation units, each of which is composed of a pixel, a fiber optic probe, a coupler and an output fiber optic. The pixel is composed of four thermal radiation pixels, namely, a broadband metamaterial thermal radiation pixel 1, a broadband metamaterial thermal radiation pixel 2, a tunable linear spectrum metamaterial thermal radiation pixel and a tunable narrowband metamaterial thermal radiation pixel. The four thermal radiation pixels are respectively connected to the input end of the coupler through the fiber optic probe, and the output fiber is connected to the output end of the coupler. Through the combination of the broadband metamaterial thermal radiation pixel 1 and the broadband metamaterial thermal radiation pixel 2, the radiation band has an emissivity of more than 0.9 in the range of 400nm to 3500nm.

[0011] Furthermore, the broadband metamaterial thermal radiation pixel 1 is composed of a vanadium substrate, vanadium cylinders integrally formed and arranged in an array on its surface, and a titanium dioxide thin film layer coated on its surface. The period of the vanadium cylinder array is 300nm, the height is 90nm, the thickness of the titanium dioxide thin film layer is 50nm, the thickness of the vanadium substrate below the vanadium cylinder is 2mm, the diameter of the vanadium cylinder is 160nm, and the diameter of the cylinder after the vanadium cylinder is coated with the titanium dioxide thin film layer is 260nm.

[0012] Furthermore, the broadband metamaterial thermal radiation pixel 2 is composed of a vanadium substrate, cylindrical pits integrally formed and arranged in an array on its surface, and a titanium dioxide thin film layer coated on its surface. The period of the cylindrical pit array is 1400nm, the depth is 560nm, the thickness of the titanium dioxide thin film layer is 175nm, the thickness of the vanadium substrate below the cylindrical pits is 2mm, the diameter of the cylindrical pits is 1260nm, and the diameter of the pits after the cylindrical pits are coated with the titanium dioxide thin film layer is 910nm.

[0013] Furthermore, the tunable linear spectral metamaterial thermal radiation pixel is composed of a gold substrate, an indium tin oxide film, a silicon nitride film and a silicon nitride rectangular grating arranged in an array on its surface from bottom to top. The silicon nitride rectangular grating has a period of 600nm, a side length of 300nm, and a height of 90nm. The thickness of the silicon nitride film is 190nm, the thickness of the indium tin oxide film is 150nm, and the thickness of the gold substrate is 2mm.

[0014] Furthermore, the tunable narrowband metamaterial thermal radiation pixel is composed of an aluminum substrate, a silicon nitride film and silver gratings arranged in lines and at equal intervals on its surface from bottom to top. The period of the silver grating is 500nm, the line width is 450nm, the height is 30nm, the thickness of the silicon nitride film is 290nm, and the thickness of the aluminum substrate is 2mm.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: in view of the diversity of the radiation spectrum of the metamaterial thermal radiator and the requirements of infrared scene generation for continuous spectrum, linear spectrum and narrow-band spectrum, the present invention can generate infrared scenes with fine spectral structure characteristics, and has great application prospects in high-precision testing and evaluation of guided weapons, precision guidance, target authenticity identification, etc., and is helpful to promote the improvement of target recognition accuracy and anti-interference characteristics of infrared imaging guidance systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the infrared scene generating device of the present invention;

[0017] Figure 2 This is a schematic diagram of the structure of a broadband metamaterial thermal radiation pixel 1 in the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of the broadband metamaterial thermal radiation pixel 2 in the present invention;

[0019] Figure 4 is a radiation spectrum diagram of a broadband metamaterial thermal radiation pixel 1 in the present invention;

[0020] Figure 5 is a radiation spectrum diagram of the second broadband metamaterial thermal radiation pixel in the present invention;

[0021] Figure 6 It is a schematic diagram of the structure of the tunable linear spectrum metamaterial thermal radiation pixel in the present invention;

[0022] Figure 7 is a radiation spectrum diagram of a thermal radiation pixel of a tunable linear spectrum metamaterial in the present invention;

[0023] Figure 8 It is a schematic diagram of the structure of the tunable narrow-band metamaterial thermal radiation pixel in the present invention;

[0024] Fig. 9 It is a radiation spectrum diagram of the tunable narrow-band metamaterial thermal radiation pixel in the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, an infrared scene generation device based on metamaterial thermal radiation is composed of an array of N radiation units, each of which is composed of a pixel, a fiber optic probe, a coupler and an output fiber. The pixel is composed of four thermal radiation pixels, namely, a broadband metamaterial thermal radiation pixel 1, a broadband metamaterial thermal radiation pixel 2, a tunable linear spectrum metamaterial thermal radiation pixel and a tunable narrowband metamaterial thermal radiation pixel. The four thermal radiation pixels are respectively connected to the input end of the coupler through the fiber optic probe, and the output fiber is connected to the output end of the coupler.

[0027] Combination Figure 2 As shown, the broadband metamaterial thermal radiation pixel 1 is composed of a vanadium substrate, vanadium cylinders integrally formed on its surface and arranged in an array, and a titanium dioxide film layer coated on its surface. Among them, the period Λ1 of the vanadium cylinder array is 300nm, the height d1 is 90nm, the thickness d2 of the titanium dioxide film layer is 50nm, the thickness d3 of the vanadium substrate below the vanadium cylinder is 2mm, the diameter D1 of the vanadium cylinder is 160nm, and the diameter D2 of the cylinder formed after the vanadium cylinder is coated with the titanium dioxide film layer is 260nm.

[0028] Combination Figure 4 As shown, the emissivity of broadband metamaterial thermal radiation pixel 1 in the 400nm~1600nm band is above 0.93. With the increase of the exit angle θ, the emissivity decreases slightly with fluctuation, but is generally insensitive to the exit angle, ensuring a higher emissivity.

[0029] Combination Figure 3As shown, the broadband metamaterial thermal radiation pixel 2 is composed of a vanadium substrate, cylindrical pits integrally formed on its surface and arranged in an array, and a titanium dioxide film layer coated on its surface. Among them, the period Λ2 of the cylindrical pit array is 1400nm, the depth d4 is 560nm, the thickness d5 of the titanium dioxide film layer is 175nm, the thickness d6 of the vanadium substrate below the cylindrical pit is 2mm, the diameter D4 of the cylindrical pit is 1260nm, and the diameter D3 of the pit after the cylindrical pit is coated with the titanium dioxide film layer is 910nm.

[0030] Combination Figure 5 As shown, the emissivity of broadband metamaterial thermal radiation pixel 2 in the 1600nm~3500nm band is above 0.9. With the increase of the exit angle θ, the emissivity decreases slightly with fluctuation, but is generally insensitive to the exit angle, ensuring a higher emissivity.

[0031] By combining broadband metamaterial thermal radiation pixel one and broadband metamaterial thermal radiation pixel two, the radiation band of the infrared scene generation device of the present invention can be broadened to 3100nm, and it has a very high emissivity in the 400nm to 3500nm band, and the emissivity in a large emission angle range is maintained at a high value of more than 0.9.

[0032] Combination Figure 6 As shown, the tunable linear spectral metamaterial thermal radiation pixel is composed of a gold substrate, an indium tin oxide film, a silicon nitride film, and a silicon nitride rectangular grating arranged on its surface from bottom to top. Among them, the period Λ3 of the silicon nitride rectangular grating is 600nm, the side length w1 is 300nm, the height d7 is 90nm, the thickness d8 of the silicon nitride film is 190nm, the thickness d9 of the indium tin oxide film is 150nm, and the thickness d 10 is 2mm.

[0033] Combination Figure 7 As shown in the figure, by changing the angle between the thermal radiation pixel of the tunable linear spectrum metamaterial and the axis of the corresponding optical fiber probe, a tunable linear spectrum can be obtained. When the emission angle θ changes continuously from small to large, the peak wavelength of the linear spectrum continuously shifts from short wave to long wave according to a linear law, and the linear spectrum can dynamically supplement the details of the continuous radiation spectrum.

[0034] Combination Figure 8 As shown in FIG. 1 , the tunable narrowband metamaterial thermal radiation pixel is composed of an aluminum substrate, a silicon nitride film, and silver gratings arranged in lines and at equal intervals on its surface from bottom to top. The silver grating has a period Λ4 of 500nm, a line width w2 of 450nm, and a height d 11 The thickness of the silicon nitride film is 30nm. 12 is 290nm, the thickness of the aluminum substrate d 13is 2mm.

[0035] Combination Fig. 9 As shown in the figure, by changing the angle between the tunable narrowband metamaterial thermal radiation pixel and the corresponding optical fiber probe axis, a tunable narrowband spectrum can be obtained. When the output angle θ changes continuously from small to large, the peak wavelength of the spectrum shifts continuously from short wave to long wave, and the narrowband spectrum can dynamically supplement the details of the continuous radiation spectrum.

[0036] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0037] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An infrared scene generation device based on metamaterial thermal radiation, characterized in that: The invention is composed of an array of N radiation units, each of which is composed of a pixel, a fiber probe, a coupler and an output fiber. The pixel is composed of four thermal radiation pixels, namely, a broadband metamaterial thermal radiation pixel 1, a broadband metamaterial thermal radiation pixel 2, a tunable linear spectrum metamaterial thermal radiation pixel and a tunable narrowband metamaterial thermal radiation pixel. The four thermal radiation pixels are respectively connected to the input end of the coupler through the fiber probe, and the output fiber is connected to the output end of the coupler. Through the combination of the broadband metamaterial thermal radiation pixel 1 and the broadband metamaterial thermal radiation pixel 2, the radiation band has an emissivity of more than 0.9 in the range of 400nm to 3500nm.

2. The infrared scene generation device based on metamaterial thermal radiation according to claim 1, characterized in that: The broadband metamaterial thermal radiation pixel 1 is composed of a vanadium substrate, vanadium cylinders integrally formed on its surface and arranged in an array, and a titanium dioxide thin film layer coated on its surface. The period of the vanadium cylinder array is 300nm, the height is 90nm, the thickness of the titanium dioxide thin film layer is 50nm, the thickness of the vanadium substrate below the vanadium cylinder is 2mm, the diameter of the vanadium cylinder is 160nm, and the diameter of the cylinder after the vanadium cylinder is coated with the titanium dioxide thin film layer is 260nm.

3. The infrared scene generation device based on metamaterial thermal radiation according to claim 1, characterized in that: The broadband metamaterial thermal radiation pixel 2 is composed of a vanadium substrate, cylindrical pits integrally formed on its surface and arranged in an array, and a titanium dioxide thin film layer coated on its surface. The period of the cylindrical pit array is 1400nm, the depth is 560nm, the thickness of the titanium dioxide thin film layer is 175nm, the thickness of the vanadium substrate below the cylindrical pits is 2mm, the diameter of the cylindrical pits is 1260nm, and the diameter of the pits after the cylindrical pits are coated with the titanium dioxide thin film layer is 910nm.

4. The infrared scene generation device based on metamaterial thermal radiation according to claim 1, characterized in that: The tunable linear spectral metamaterial thermal radiation pixel is composed of a gold substrate, an indium tin oxide film, a silicon nitride film and a silicon nitride rectangular grating arranged in an array on its surface from bottom to top. The silicon nitride rectangular grating has a period of 600nm, a side length of 300nm, and a height of 90nm. The thickness of the silicon nitride film is 190nm, the thickness of the indium tin oxide film is 150nm, and the thickness of the gold substrate is 2mm.

5. The infrared scene generation device based on metamaterial thermal radiation according to claim 1, characterized in that: The tunable narrowband metamaterial thermal radiation pixel is composed of an aluminum substrate, a silicon nitride film and silver gratings arranged in lines and at equal intervals on its surface from bottom to top. The silver grating has a period of 500nm, a line width of 450nm, and a height of 30nm. The thickness of the silicon nitride film is 290nm, and the thickness of the aluminum substrate is 2mm.

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