Abstract:As precision guided weapons, missiles have been widely used in the battlefield, and corresponding countermeasures are also developing rapidly. Infrared decoy has become an important factor affecting the combat effectiveness of the guided missile with photoelectric seeker. In order to study the anti-decoy jamming ability of infrared self-homing missile, the physical effect environment of missile flight under the condition of infrared decoy jamming is constructed by using hardware-in-the-loop simulation system, and the anti-infrared decoy jamming ability of missile is analyzed in this paper. Through the hardware-in-the-loop simulation test, it can be seen that setting the distance between target and decoy properly can induce infrared guided missile to attack stationary target. For maneuvering target, if the decoy is placed at the right time, it can effectively induce infrared guided missile attack.

Abstract:The electrical and optical properties of narrow gap semiconductor mercury cadmium telluride materials directly affect the performance of infrared detectors. Doping is an effective means to improve the material properties, so it is very important to study the doping of mercury cadmium telluride materials. A step-scanning Fourier transform infrared modulated photoluminescence (FTIR-PL) spectrometer was used to measure the temperature change of In-doped mercury cadmium telluride in different annealing conditions. The signal-to-noise ratio (SNR) during the experiment was reduced and a better spectra was obtained. Based on the results, combining the Hall data, the change of energy level position caused by temperature change was analyzed as well as the change of luminescent peak intensity and position of mercury cadmium telluride materials after different annealing conditions.

Abstract:The dewar cold head structure of the infrared detector is easily damaged by temperature impact, which directly leads to the failure of infrared detector components. This is one of the inevitable reliability problems in the development of infrared detector components. The low temperature reliability of the dewar cold head in the infrared detector was studied. Combined with the bonding failure principle and finite element simulation, the influence of adhesive thickness and overflow on the low temperature stress of dewar cold head, the relationship between the bonding area of cold head and cold finger and the detector temperature was discussed. The results show that the state of the adhesive layer is an important factor affecting the low temperature damage and temperature conduction of the dewar cold head. In the process of product development, the low temperature stress of the large array detector bonding structure can be reduced by controlling the adhesive layer, so as to improve the low temperature reliability of the cold head structure.

Abstract:In view of the phenomenon that the cooling head structure of an infrared detector is abnormal, the thermal resistance becomes large and the cooling head chip is not warm, the related research is carried out. In this paper, Ansys finite element software is used to carry out the simulation analysis of the cold head structure of the infrared detector. And the optimization design is carried out according to the analysis results. Through simulation analysis, it is found that under the condition of ensuring the low temperature stress and low temperature deformation of the detector chip, the stresses on the surface of the cold head and the structural parts of the cold head are significantly reduced. According to the optimized cold head structure, three new state infrared detector components are assembled. And 1000 times of aging experiments are conducted. The results show that the strength of cold head, non-uniformity of detector response, blind element rate and other key indicators do not change before and after the experiment. It is confirmed that the optimized cold head structure has higher reliability, which is beneficial to the long-term use of the detector, and the optimization scheme is reasonable.

Abstract:In order to improve the output power of 1342 nm distributed feedback (DFB) semiconductor laser, three kinds of cavity surface film combinations are designed in this paper. Electron beam evaporation coating technology is used to coat the cavity surface of the laser, and the output power of the laser under three kinds of film combinations is tested. The results show that the highest output power of 1342 nm DFB semiconductor laser is obtained by using the combination of cavity surface film system (antireflective film: Sub/Al₂O₃/Ta₂O₅/Air, high reflection film: Sub/(Al₂O₃/Si)³Al₂O₃/Air). The reflectance of the anterior cavity surface is 0.2%, and that of the posterior cavity surface is 98.6%. At 260 mA DC, the average output power reaches more than 85 mW (an increase of 85.6%), and the slope efficiency increases by 82.9%. The output power of the laser can be greatly improved by coating the cavity surface of the laser with this combination of film systems.

Abstract:The key of forest fire prevention is to predict the fire risk effectively through the real-time fire monitoring system. By analyzing the application of UAVs in forest fire prevention, a medium wave infrared camera system for forest fire real-time monitoring based on UAVs is proposed in this paper. The focal length is 75 mm, the wavelength band is 3.7－4.8 μm, F number is 2.0. The system can match a 1280×1024 cooled MWIR focal plane detector with pixel size of 12 μm×12 μm. In the optical design, three infrared optical materials (silicon, zinc selenide and germanium) are combined, and three even aspheric surfaces are introduced. The passive athermal optical design is realized as well. The design results show that the modulation transfer function (MTF) of each field of view is greater than or close to 0.4 at the spatial frequency of 41.7 lp /mm in the temperature range of -60~100℃, which has good imaging quality. Since the medium wave infrared system has high imaging quality and resolution, large field of view, adaptability in wide temperature range, compact structure and can be installed easily，it has a wide application prospect in the field of forest fire prevention.

Abstract:In order to find out a fast, simple and accurate method to explore the types of mold growing on the surface of weapons and equipment after mold test, the mold test according to the standard test method is conducted in this paper. Fourier infrared spectrometer is used to test the samples corroded by different strains. Spectral data are obtained, and the identification region of spectral data is determined by principal component analysis. The minimum distance matching, spectral angle matching, spectral information divergence, spectral covariance, principal component analysis, PLS-DA and random forest are used to establish the recognition model. The results show that mold species can be identified well by the random forest algorithm, and the accuracy is expected to be more than 98%. Based on the appropriate classification algorithm, FTIR technology can realize the effective identification of bacterial species.