Abstract:InAs/GaSb type-II superlattice materials are the preferred materials for the third-generation infrared focal plane detectors. An InAs/GaSb type-II superlattice long-wavelength infrared focal plane device with array size of 320×256 and pixel pitch of 30 μm is reported. At 77 K, the average peak detectivity of the device is 7.6×10¹⁰ cm·Hz^1/2·W^-1, the blind element rate is 1.46%, the response non-uniformity is 7.55%, and the noise equivalent temperature difference (NETD) is 25.5 mK. The calculation shows that the peak quantum efficiency of this device is 26.2%, and the 50% cut-off wavelength is 9.1 μm. Finally, an imaging demonstration of the device is carried out. The results show that the research has laid the foundation for the subsequent development of related devices.

Abstract:According to the requirements of the current cooled infrared focal plane array (IRFPA) detector for the cooling start-up time (quick start), the specific factors that affect the start-up time of the detector are analyzed. The results show that the cooling rate of the cold platform parts has a certain degree of influence on the start-up time of the detector. The current domestic thermal conductivity materials are investigated. A material matching the infrared detector hybrid chip is found, and the preliminary process of the material is verified.

Abstract:In order to improve the temperature control precision of the bellows-type J-T cooler, the needle design is optimized. The tip of the needle is grooved to form double throttled holes with the main throttled hole on the valve body of the cooler. The working medium enters the main throttled hole for throttling and cooling after the start. The hole is completely blocked by the needle after self-regulating of the cooler, and the steady small flow is ejected from the groove.The reasonable size of the groove is determined. The test results show that the groove on the tip of the needle can effectively improve the temperature control precision.

Abstract:The multi-motor cooperative control scheme of ultra-long focal length continuous zoom system is an important design link to ensure the imaging quality and effect. In this paper, the control and demand indexes of a continuous zoom thermal imager are analyzed, and the advantages and disadvantages of various control schemes are discussed in detail based on the index data. In addition, according to the results, a multi-motor cooperative control scheme based on SOPC system-on-chip is designed. The specific design and software implementation method of the scheme in continuous zoom system are described in detail. The design can realize multi-component cooperative control on a single FPGA. The time and position accuracy can reach 0.01 μs level and 0.01 mm level respectively, which effectively ensure the control requirements of the ultra-long focal length continuous zoom system.

Abstract:When the temperature changes, the position of optical elements in the spectrometer will change due to hot expansion and cold contraction, resulting in a large deviation of wavelength. In response to this problem, the wavelength calibration method suitable for different temperatures was studied. A method of wavelength calibration based on temperature compensation was proposed, using temperature as a variable to establish a theoretical model of three-dimensional functional relation between wavelength, pixel position and temperature. A standard mercury-argon lamp was used for calibration experiments. The coefficients of the polynomials were determined by cubic polynomial surface fitting, which verified the calibration accuracy under high and low temperature environments. This method can effectively correct the change of charge coupled device response and the deviation of optical path structure caused by temperature, improve the fault tolerance of wavelength correction coefficient and the wavelength accuracy when the temperature changes, and improve the environmental adaptability of the spectrometer.

Abstract:In order to select optimal spectral features at the minimum cost, a Filter type algorithm for spectral feature selection is proposed from the perspective of information loss. The algorithm sorts the features according to the joint mutual information size and uses a zero information loss principle to judge and reduce the redundant features of the sorted feature set. In this way, a small and optimal subset of spectral features can be obtained, which can represent the whole original spectral features, and the information loss caused by the deletion of redundant features can be reduced.

Abstract:The brightness temperature bias of the medium wave channel of the variational assimilation geostationary interferometric infrared sounder (GIIRS) of FY-4 is required to meet the Gaussian distribution, so the bias correction of GIIRS data is necessary. Based on Harris B A and Kelly G ′s "off-line" method, a method for GIIRS bias correction based on the random forest is developed in this paper. In the specific implementation process, the cloud detection of GIIRS data is carried out based on the advanced geosynchronous radiation imager (AGRI) cloud products of FY-4. The experimental results show that the brightness temperature bias of GIIRS satisfies the assumption of Gaussian distribution after the bias correction. Compared with "off-line" method, random forest method has a better correction effect.

Abstract:In recent years, microelectronics technology has become the "main battlefield" of US-China technology and trade war. The US ′s global leadership in microelectronics technology and the security of the microelectronics supply chain have both been threatened. In this context, the U.S. Department of Defense has been vigorously promoting the development of microelectronics technology by establishing research and development programs and increasing funding. This strategic plan is comprehensively analyzed from the main background, development trends, and significance of influence.