An infrared scene generation device based on metamaterial thermal radiation

Abstract

An infrared scene generation device based on metamaterial thermal radiation is disclosed, relating to the field of infrared scene generation technology. It consists of a radiation unit array, each radiation unit comprising a pixel, a fiber optic probe, a coupler, and an output fiber. The pixel comprises a broadband metamaterial thermal radiation pixel one, a broadband metamaterial thermal radiation pixel two, a tunable line-spectral metamaterial thermal radiation pixel, and a tunable narrowband metamaterial thermal radiation pixel. The four thermal radiation pixels are connected to the input end of the coupler via fiber optic probes, and the output fiber is connected to the output end of the coupler. Using metamaterial thermal radiation pixels enables more flexible generation of infrared scenes with finely structured spectra, contributing to improved target recognition accuracy and anti-interference characteristics of infrared imaging guidance systems.

Description

Technical Field

[0001] This invention relates to the field of infrared scene generation technology, specifically an infrared scene generation device based on metamaterial thermal radiation. Background Technology

[0002] Infrared imaging guidance technology utilizes infrared cameras to capture and track the energy radiated by a target to achieve homing guidance. It boasts advantages such as high sensitivity, high accuracy, high spatial resolution, large dynamic tracking range, long effective range, and strong anti-interference capabilities. However, testing and training infrared imaging guidance systems in real-world scenarios presents challenges including high difficulty, high cost, long development cycles, and poor repeatability. Infrared imaging guidance hardware-in-the-loop (HIL) simulation technology can address these issues, enabling comprehensive testing and evaluation of guided weapon performance. Infrared scene generation technology is the core technology of this HIL simulation system, used to simulate the light radiation of an infrared scene for reception by the imaging system (such as the seeker).

[0003] Infrared decoy flares mimic the light radiation of a protected target by generating a high-temperature flame through combustion, thus deceiving and interfering with infrared imaging guidance systems. The radiation spectrum of infrared decoy flares is similar to that of aircraft exhaust plumes, requiring seekers to continuously improve their ability to distinguish between targets and decoys to cope with the development of infrared decoy technology. Multispectral imaging guidance technology improves the seeker's ability to distinguish between targets and decoys by acquiring and comparing multispectral images of targets and decoy flares in an infrared scene. The development of multispectral imaging guidance technology places higher demands on infrared imaging guidance hardware-in-the-loop simulation technology; infrared scene generation needs to provide detailed and realistic spectra to meet simulation requirements.

[0004] Infrared scene generation methods can be divided into two categories: direct radiation type and radiation modulation type. Direct radiation type infrared scene generation methods utilize pixel arrays to generate infrared radiation and control the radiation intensity of each pixel to generate the desired infrared scene. Examples include resistor arrays that radiate continuous spectrum, infrared light-emitting diode arrays that radiate narrowband spectrum, and infrared laser diode arrays that radiate line spectrum. Radiation modulation type infrared scene generation methods generate the desired infrared scene by spatially modulating the infrared light source illuminating an infrared spatial light modulator. For example, each pixel of a digital micromirror device modulates a blackbody light source to generate the desired two-dimensional light distribution, and its radiation spectrum is a continuous spectrum.

[0005] Since the 1980s, resistive arrays have dominated the field of infrared scene generation, with the development of devices in three pixel structures: thin film, bridge, and suspended thin film. However, the apparent temperature of resistive arrays is limited to around 700K, and their response speed is low. In 2016-2017, Santa Barbara Infrared Corporation in the United States overcame these shortcomings, developing resistive arrays with an apparent temperature exceeding 1500K and a frame rate of 500Hz. On the other hand, experimental results have demonstrated that infrared LEDs possess advantages such as an apparent temperature exceeding 1000K, fast response speed, and large dynamic range, leading to the development of infrared LED arrays in the field of infrared scene generation. In 2016, the University of Delaware and the University of Iowa developed a 512×512 pixel infrared LED array and achieved an apparent temperature of 1350K. In 2019, the University of Delaware and Hockessin Chip Design Systems, LLC proposed a modular and scalable infrared LED array design method and demonstrated infrared scene generation results. Domestically, from 2016 to 2018, Beijing Institute of Technology researched an infrared scene generation method based on visible light / infrared image conversion thin films. In 2018, the China Air-to-Air Missile Research Institute designed a multi-spectral target simulation system based on resistive array optical alignment. Harbin Institute of Technology has also conducted extensive research in the field of infrared scene generation. From 2014 to 2016, the inventors used micro-optical beam expander technology to study a multi-interference optical path infrared scene generation system, and in 2019, they studied an image-side telecentric optical path optical system to suppress cold reflections from resistive arrays.

[0006] However, the infrared exhaust plume of targets and the infrared radiation of infrared decoys in infrared scenes usually contain continuous spectrum, line spectrum and narrowband spectrum. Although existing infrared scene generation methods at home and abroad can simulate the energy distribution of target and decoy radiation, they are still inconsistent with the target and decoy radiation in terms of fine spectral structure features.

[0007] Metamaterials are a new class of materials that emerged in the 21st century. They are man-made materials with unique properties that do not exist in nature, possessing special functions that traditional materials cannot achieve, such as negative refractive index, electromagnetic stealth, and the anti-Doppler effect. The rise of metamaterials has brought new opportunities and hope to the development of traditional infrared thermal radiation technology, becoming one of the most dynamic research directions in the field. Metamaterial absorbers were first proposed in 2008 by Boston College and Duke University. By adjusting the microstructure of the metamaterial absorber, 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 equals its absorptivity. Research on using heated metamaterial absorbers as metamaterial thermal radiators has also been carried out. In 2015, Arizona State University and RMIT University jointly studied a metamaterial absorber composed of a two-dimensional titanium grating, a magnesium fluoride dielectric film, and a tungsten metal film. This metamaterial absorber exhibited good stability in its measured spectrum within a temperature range of 23.5–350 °C. Due to the wavelength selectivity of the broadband radiation spectrum of metamaterial thermal radiators, their application in thermophotovoltaic systems can improve the system's energy conversion efficiency. In 2018, Physical Sciences Corporation, Sandia National Laboratories, and MIT Lincoln Laboratory jointly developed a metamaterial thermal radiator for thermophotovoltaic systems and verified that heating the metamaterial thermal radiator to 1055℃ achieves a higher thermoelectric conversion efficiency than conventional thermal radiators. In 2019, the Technical University of Hamburg, Germany, in collaboration with its partners, studied the high-temperature resistance of metamaterial thermal radiators, experimentally demonstrating that their developed metamaterial thermal radiator can maintain a stable radiation spectrum at an operating temperature of 1400℃. Domestically, the Institute of Optics, Electronics and Physics, Chinese Academy of Sciences, developed a metamaterial absorber operating in the 200–900 nm wavelength band in 2018. The test spectrum of this metamaterial absorber after annealing at 600℃ was basically consistent with the test spectrum before heating. In 2018, Zhejiang University developed a dual-band metamaterial thermal radiator and tested its spectral characteristics within the temperature range of 100–203℃. In 2019, Shanghai Jiao Tong University, in collaboration with other institutions, developed an all-dielectric metamaterial absorber. Experimental results demonstrated that the absorber's spectrum remained essentially unchanged within the temperature range of 0–100℃. Although research results on metamaterial absorbers and metamaterial thermal radiators with line spectra and narrowband spectra have been reported, achieving spectral tunability remains challenging. Harbin Institute of Technology has conducted extensive research on the design, fabrication, and testing of metamaterial absorbers. The inventors have conducted in-depth studies on the generation and tuning mechanisms of line and narrowband spectra based on guided-mode resonance, and in 2019, they developed a tunable line-spectral metamaterial absorber based on guided-mode resonance. Significant progress has also been made in developing a tunable narrowband-spectral metamaterial absorber based on guided-mode resonance.To simplify the structure of broadband metamaterial absorbers, the inventors developed a simple two-layer two-dimensional cylindrical array structure broadband metamaterial absorber in 2020.

[0008] In summary, although significant progress has been made in the research of metamaterial absorbers and metamaterial thermal radiators both domestically and internationally, their application in infrared scene generation methods remains a blank. Summary of the Invention

[0009] To address the shortcomings of the prior art, this invention provides an infrared scene generation device based on metamaterial thermal radiation. The device utilizes metamaterial thermal radiation pixels to more flexibly generate infrared scenes with fine-structured spectra, which helps to improve the target recognition accuracy and anti-interference characteristics of infrared imaging guidance systems.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: an infrared scene generation device based on metamaterial thermal radiation, comprising an array of N radiation units. Each radiation unit consists of a pixel, an optical fiber probe, a coupler, and an output optical fiber. The pixel comprises four thermal radiation pixels: a broadband metamaterial thermal radiation pixel one, a broadband metamaterial thermal radiation pixel two, a tunable linear spectral 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 optical fiber probe, and the output optical fiber is connected to the output end of the coupler. By combining the broadband metamaterial thermal radiation pixel one and the broadband metamaterial thermal radiation pixel two, an emissivity of over 0.9 is achieved in the radiation band from 400nm to 3500nm.

[0011] Furthermore, the broadband metamaterial thermal radiation pixel 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 300 nm, the height is 90 nm, the thickness of the titanium dioxide thin film layer is 50 nm, the thickness of the vanadium substrate below the vanadium cylinders is 2 mm, the diameter of the vanadium cylinders is 160 nm, and the diameter of the cylinder formed after the vanadium cylinders are coated with the titanium dioxide thin film layer is 260 nm.

[0012] Furthermore, the broadband metamaterial thermal radiation pixel II 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 1400 nm, the depth is 560 nm, the thickness of the titanium dioxide thin film layer is 175 nm, the thickness of the vanadium substrate below the cylindrical pits is 2 mm, the diameter of the cylindrical pits is 1260 nm, and the diameter of the pits formed after the cylindrical pits are coated with the titanium dioxide thin film layer is 910 nm.

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

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

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: Given the diverse radiation spectrum of metamaterial thermal radiators, and considering the requirements of infrared scene generation for continuous spectrum, line spectrum, and narrowband spectrum, the present invention can generate infrared scenes with fine spectral structure features. It has great application prospects in high-precision testing and evaluation of guided weapons, precision guidance, and target authenticity identification, and helps to improve the target recognition accuracy and anti-interference characteristics of infrared imaging guidance systems. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the infrared scene generation device of the present invention;

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

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

[0019] Figure 4 This is the radiation spectrum of the first thermal radiation pixel of the broadband metamaterial in this invention;

[0020] Figure 5 This is the radiation spectrum of the second thermal radiation pixel of the broadband metamaterial in this invention;

[0021] Figure 6 This is a schematic diagram of the structure of the tunable linear spectral metamaterial thermal radiation pixel in this invention;

[0022] Figure 7 This is the radiation spectrum of the thermal radiation pixel of the tunable linear spectral metamaterial in this invention;

[0023] Figure 8 This is a schematic diagram of the structure of the tunable narrowband metamaterial thermal radiation pixel in this invention;

[0024] Figure 9 This is the radiation spectrum of the tunable narrowband metamaterial thermal radiation pixel in this invention. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, an infrared scene generation device based on metamaterial thermal radiation is provided, which consists of an array of N radiation units. Each radiation unit consists of a pixel, an optical fiber probe, a coupler, and an output optical fiber. The pixel consists of four thermal radiation pixels: a broadband metamaterial thermal radiation pixel one, a broadband metamaterial thermal radiation pixel two, a tunable linear spectral 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 optical fiber probe, and the output optical fiber is connected to the output end of the coupler.

[0027] Combination Figure 2 As shown, the broadband metamaterial thermal radiation pixel consists 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 vanadium cylinder array has a period Λ1 of 300 nm, a height d1 of 90 nm, a titanium dioxide thin film layer thickness d2 of 50 nm, a vanadium substrate thickness d3 below the vanadium cylinders of 2 mm, a vanadium cylinder diameter D1 of 160 nm, and a diameter D2 of 260 nm after the vanadium cylinders are coated with the titanium dioxide thin film layer.

[0028] Combination Figure 4 As shown, the emissivity of the broadband metamaterial thermal radiation pixel is above 0.93 in the 400nm to 1600nm band. The emissivity decreases slightly with the increase of the emission angle θ, but it is not sensitive to the emission angle overall, thus ensuring a high emissivity.

[0029] Combination Figure 3As shown, the broadband metamaterial thermal radiation pixel II consists 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 Λ2 of the cylindrical pit array is 1400 nm, the depth d4 is 560 nm, the thickness d5 of the titanium dioxide thin film layer is 175 nm, the thickness d6 of the vanadium substrate below the cylindrical pits is 2 mm, the diameter D4 of the cylindrical pits is 1260 nm, and the diameter D3 of the pits formed after coating with the titanium dioxide thin film layer is 910 nm.

[0030] Combination Figure 5 As shown, the emissivity of the broadband metamaterial thermal radiation pixel II is above 0.9 in the 1600nm to 3500nm band. The emissivity decreases slightly with the increase of the emission angle θ, but it is not sensitive to the emission angle overall, thus ensuring a high 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 is maintained at a high value of 0.9 or above in a large emission angle range.

[0032] Combination Figure 6 As shown, the tunable linear spectral metamaterial thermal radiation pixel, from bottom to top, consists of a gold substrate, an indium tin oxide (ITO) thin film, a silicon tetranitride (SiN) thin film, and a SiN rectangular grating arrayed on its surface. Specifically, the SiN rectangular grating has a period Λ3 of 600 nm, a side length w1 of 300 nm, a height d7 of 90 nm, a SiN film thickness d8 of 190 nm, an ITO film thickness d9 of 150 nm, and a gold substrate thickness d... 10 It is 2mm.

[0033] Combination Figure 7 As shown, a tunable line spectrum can be obtained by changing the angle between the thermal radiation pixels of the tunable line spectral metamaterial and the axis of the corresponding fiber optic probe. When the emission angle θ changes continuously from small to large, the peak wavelength of the line spectrum shifts linearly from short wavelength to long wavelength, and this line spectrum can dynamically supplement the details of the continuous radiation spectrum.

[0034] Combination Figure 8 As shown, the tunable narrowband metamaterial thermal radiation pixel consists of an aluminum substrate, a silicon tetranitride thin film, and silver gratings arranged in a linear pattern at equal intervals on its surface, from bottom to top. The period Λ4 of the silver grating is 500 nm, the linewidth w2 is 450 nm, and the height d... 11 The thickness d of the 30nm silicon tetranitride thin film 12 The thickness d of the aluminum substrate is 290nm. 13It is 2mm.

[0035] Combination Figure 9 As shown, a tunable narrowband spectrum can be obtained by changing the angle between the tunable narrowband metamaterial thermal radiation pixel and the corresponding fiber optic probe axis. When the emission angle θ changes continuously from small to large, the peak wavelength of the spectrum shifts continuously from short wavelength to long wavelength, and this 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 present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments 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: Composed of an array of N radiating units, each radiating unit consists of a pixel, an optical fiber probe, a coupler, and an output optical fiber. Each pixel comprises four thermal radiation pixels: a broadband metamaterial thermal radiation pixel one, a broadband metamaterial thermal radiation pixel two, a tunable line-spectral metamaterial thermal radiation pixel, and a tunable narrowband metamaterial thermal radiation pixel. These four thermal radiation pixels are connected to the input end of the coupler via optical fiber probes, and the output optical fiber is connected to the output end of the coupler. By combining the broadband metamaterial thermal radiation pixel one and the broadband metamaterial thermal radiation pixel two, an emissivity of over 0.9 is achieved in the radiation band from 400 nm to 3500 nm. The broadband metamaterial thermal radiation pixel one consists of a vanadium substrate, vanadium cylinders integrally formed on its surface and arranged in an array, and a carbon dioxide coating on its surface. The first broadband metamaterial consists of a titanium dioxide thin film layer, a vanadium cylindrical array with a period of 300 nm and a height of 90 nm, a titanium dioxide thin film layer with a thickness of 50 nm, a vanadium substrate with a thickness of 2 mm below the vanadium cylinders, a vanadium cylinder with a diameter of 160 nm, and a cylinder with a diameter of 260 nm after being coated with a titanium dioxide thin film layer. The second broadband metamaterial consists 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 cylindrical pit array has a period of 1400 nm and a depth of 560 nm, a titanium dioxide thin film layer with a thickness of 175 nm, a vanadium substrate with a thickness of 2 mm below the cylindrical pits, a cylindrical pit with a diameter of 1260 nm, and a pit with a diameter of 910 nm after being coated with a titanium dioxide thin film layer.

2. 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 consists of a gold substrate, an indium tin oxide film, a silicon tetranitride film, and a silicon tetranitride rectangular grating arrayed on its surface, from bottom to top. The silicon tetranitride rectangular grating has a period of 600 nm, a side length of 300 nm, and a height of 90 nm. The silicon tetranitride film has a thickness of 190 nm, the indium tin oxide film has a thickness of 150 nm, and the gold substrate has a thickness of 2 mm.

3. The infrared scene generation device based on metamaterial thermal radiation according to claim 1, characterized in that: The tunable narrowband metamaterial thermal radiation pixel consists of an aluminum substrate, a silicon tetranitride thin film, and silver gratings arranged in a linear pattern at equal intervals on its surface, from bottom to top. The silver gratings have a period of 500 nm, a linewidth of 450 nm, and a height of 30 nm. The silicon tetranitride thin film has a thickness of 290 nm, and the aluminum substrate has a thickness of 2 mm.

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