Optical thin film technology has been widely used in almost all optical systems, photoelectric systems and photoelectric instruments. The development of new detectors puts forward filtering requirements for the energy response in the near-infrared 1--3 m band. Starting from the electromagnetic field theory and Maxwell′s equations, the design theory of optical thin films is introduced, and the design method of band-pass filter films is discussed. Using Optilayer software, a band-pass filter film in the near-infrared band is designed with alumina as the base, and the working band is 13--27 m. Considering the matching of coating materials, zinc sulfide and ytterbium fluoride are selected as high and low refractive index materials. The design method combining long wave pass and short wave pass is adopted, and the calculation and optimization of the film system are completed with Optilayer software. The film is coated on both sides of the alumina substrate, and the film system is coated by the preparation process of electron beam evaporation and ion beam-assisted deposition. The prepared samples are tested for transmittance with a spectrophotometer. The test results show that the average transmittance of the sample is greater than 95% in the design waveband of 13--27 m, which meets the requirements of the design of the band-pass filter film.

With the acceleration of the localization of our military equipment, it is necessary to evaluate the application effect of domestic core electronic devices in order to promote the engineering application of domestic core electronic devices in our military equipment. Firstly, the background and necessity of the evaluation of the application effect of domestic infrared detectors are introduced, and the application effect evaluation methods of domestic infrared detectors at the device level, module level, equipment level and system level are described in detail. The application effect of the detector in the airborne system has been scientifically evaluated, which can lead to the optimization and improvement of the domestic infrared detector, so as to support the comprehensive guarantee and reliability design of our military equipment manufacturers.

A near-infrared optical power meter circuit with large dynamic range is designed based on indium gallium arsenide (InGaAs) photodiode. It can measure near-infrared optical power in the range of -95--10 dBm without using an external optical attenuator. The optical power meter circuit adopts technologies such as automatic bias voltage control, multi-level amplification range, differential sampling circuit, etc ., and suppresses stray light noise and dark noise through electromagnetic shielding design, thereby improving the measurement dynamic range. The test results show that the dynamic range of this near-infrared optical power meter circuit reaches 105 dB, and the linearity in the range of -60--10 dBm is less than ±002 dB.

Fiber Bragg Grating (FBG) thermal flow sensing technology has the advantages of low measurement threshold and high sensitivity, and has become a research hotspot in the field of flow measurement in recent years. In this paper, the principle of FBG thermal flow sensing is summarized, and the key and difficult problems in the current sensing technology are summarized (including sensor heating, structure design, temperature compensation and package sensitization), aiming at finding problems and looking into the future. Based on the typical research results in recent years, two kinds of heating methods and hot-wire sensing structure of electric heating and optical heating are analyzed. Temperature compensation and package sensitization are studied as special topics. Among them, temperature compensation aims to solve the cross- sensitivity problem of heat transfer and ambient temperature. Finally, the low sensitivity characteristics of the sensor technology under high flow are summarized and analyzed, and the possible research directions and related methods for improving the sensor sensitivity in the future are discussed.

The infrared detector frame gluing process has the characteristics of many types of adhesives and high requirements for gluing accuracy. It is difficult to take into account the process efficiency and process effect at the same time. In order to explore a better gluing process, the effects of two gluing processes, manual gluing and silk printing, on the bonding of frames and chips are compared and analyzed based on the same frame. The results show that both silk printing and manual gluing can meet the basic requirements of adhesive curing, resistance to 100 times of temperature shock test and uniform overflow around the circuit chip. When the screen is in the concentrated punch mode, the void fraction of silk printing in the adhesives between the circuit chip and frame is less than 1%, which is 009 times that of manual gluing. When using different adhesives, the effect of the manual gluing process is not affected by the change of the filler diameter of the adhesive, while silk printing is more suitable for adhesives with small diameter fillers. Finally, according to the iterative data of silk printing plates, the empirical calculation formula of missing printing area is proposed, which provides support for accurate and fast screen plate design.

Cloud top height is the most basic and important parameter of cloud, and it is also an important parameter for studying airspace capacity, flight altitude configuration, weather forecast and early warning. The principles, advantages and disadvantages of the main methods for retrieving cloud top heights based on satellite data are described briefly in this paper. The single infrared window method, the solar reflectance-infrared window method, the H2O-infrared window method and the infrared split window zone method are introduced as the main point. And the related business algorithm of satellite is briefly reviewed. Then, the inversion of convective cloud top height by single infrared window method is verified. The results show that the inversion of opaque thick cloud by single infrared window method has high accuracy and correlation. Finally, the reasons affecting the accuracy of each method are analyzed and the future of cloud top height inversion methods is prospected.

In order to further improve the accuracy of urban ecological monitoring, the concept of "regional scale" is introduced on the basis of previous studies on urban ecological remote sensing monitoring. And the interaction between different ground objects in a small area is fully considered. The moving window-remote sensing ecology index (MW-RSEI) is used to analyze the remote sensing images based on every pixel in hunnan district of Shenyang. The experimental results show that MW-RSEI model and remote sensing ecology index (RSEI) are consistent in the overall ecological evaluation trend. MW-RSEI has a more obvious representation of detailed regions in urban ecology. Considering the influence of buildings and vegetation around bare land, the proportion of poor ecological area is only 6%, and the proportion of good ecological evaluation is 11%. The results of ecological evaluation in the study area are relatively continuous, and there is no obvious fault phenomenon, which is of practical significance and more consistent with the actual ecological distribution. The MW-RSEI model is more suitable for urban ecological monitoring and can provide technical references for related departments.