Relative spectral response is an important index for evaluating the performance parameters of infrared detectors, which directly affects the user′s usage. Using the detectors in the middle and long wave bands as experimental devices, two different test methods using Fourier spectrometer and monochromator are analyzed and discussed. For the long-wave infrared detector, the rear cut-off wavelengths of the monochromator and Fourier spectrometer are 928 m and 925 m, respectively, and the front cut-off wavelength is 760 m. For mid-wave infrared detectors, the rear cutoff wavelengths of the monochromator and Fourier spectrometer are 486 m and 485 m, respectively, and the front cutoff wavelengths are 360 m. The results show that the front-cut wavelengths of the two test methods are completely consistent, and the rear cutoff wavelengths are within the allowable error range, thus verifying the consistency and accuracy of the relative spectral response of the two instruments. The principles of the two test methods are easy to understand and operate, the results are accurate, which provides a certain reference for the optimization of infrared detector performance.

The surface of the indium antimonide focal plane device is often marked with fine lines after the traditional backside thinning process; when the traditional surface cleaning method is used, it is also easy to cause scratches on the surface of the device, resulting in poor process repeatability. Therefore, when the device is thinned on the back surface, the corrosion liquid is used to remove the scratches, and the non-contact cleaning method based on petroleum ether and absolute ethanol is adopted, which effectively reduces the probability of scratches on the surface of the device and avoids the higher level of some areas during the test due to the uneven surface corrosion rate, bright spots on the test image, etc. In addition, the process repeatability is improved, and the infrared imaging of the indium antimonide device is uniform and there is no scratch, thereby improving the yield of the device.

In order to make the missile owner achieve the purpose of penetration, the mathematical model of the surface temperature of space targets is applied to calculate the temperature field distribution of targets at different heights on the basis of analyzing the background radiation. And the influence of height on infrared radiation characteristics is analyzed and discussed. The results show that the height is not the parameter which can distinguish the decoy and the warhead by day or by night, but deployment in the day time can reduce the hit rate and achieve the penetration effect.

According to the time domain coupled mode theory, the working conditions of the photonic crystal stop-band filter with a side coupling structure of the waveguide and the approximate rectangular ring cavity resonator are analyzed. The function relationships of normalized stop-band loss L, cavity detuning factor|ω-ω0|τ0, cavity normalized loss Lc, normalized reflection R and normalized transmission T are obtained, and the stop-band loss mechanism of PCSBF is explored. The filtering performance of PCSBF within the wavelength range of 1450--1750 nm is studied by using the finite difference time domain method, which shows that the stop-bands of the output normalized power spectrum can be adjusted by changing the size of 3×n(3≤n≤9)approximate rectangular ring cavities or by changing the radius of inner rods in this PCSBF structure. 34 wide stop-bands whose average width is 5817 nm are collected from the PCSBF power spectrum, and the average value of these stop-bands signal strength decay is not less than 8035 dB. The results show that the stop-band of the structure has the characteristics of wide tenability, high normalized loss and so on. According to the actual demand, changing the PCSBF structure design to adjust the power output spectrum can effectively filter the unwanted wavelength signal, thus ensuring the stability of optical fiber communication system and integrated optical path. Therefore, this miniature stop-band component has potential application value in the optical integration, the optical communication and other fields.

Based on Landsat images in 1985, 2000 and 2017, the land cover results of Horqin sandy land from 1985 to 2017 are obtained by using support vector machine (SVM) classification method. First, we obtained land cover classification maps by using SVM classification method on Landsat images in 1985, 2000 and 2017. Then, the research area is divided into two parts: the main body of the sandy land and the hilly loess area, and the regional characteristics of the land cover change in the research area are further analyzed. The results show that from 1985 to 2000, the cultivated land area of Horqin sandy land increased significantly while the grassland area decreased probably because the household contract responsibility system was implemented during this period, which aroused the enthusiasm of herdsmen for production, and a large amount of cultivated land was reclaimed. From 2000 to 2017, the cultivated land area decreased and the grassland area increased, which is closely related to the vigorous implementation of ecological protection policies such as returning farmland to forest and grassland in this area since 2000.This change indicates that the ecological protection in the research area has achieved initial results. Further analysis shows that the cropland area in the main body of sandy land area continued to increase from 1985 to 2017, which is closely related to the development of irrigated agriculture and rice cultivation. This paper provides basic data and decision basis for improving and governing the ecological environment in Horqin area.