Abstract:The current status of the research on mercury cadmium telluride (MCT) defects is reviewed by summarizing and analyzing the related papers published in recent years. MCT offers significant advantages over other similar semiconductors. This has made it to be the most widely used narrow gap material in infrared focal plane array (FPA) devices. The defects in MCT epilayers can inhibit the pixel performance and operatability of the FPA fabricated with this material. The type, orientation, and growth temperature of the substrate etc. are the factors which have apparent effect on MCT epilayer quality. To grow high quality MCT epilayers, different factors which may result in defects should be further understood and controlled properly. Significant progresses have been made in the epitaxial growth of MCT with the aid of various fabrication and characterization techniques.

Abstract:The characteristics of the adhesion between a thin film and its substrate have been being much concerned. The performance of the thin film depends on the adhesion between the film and its substrate in all cases. To enhance the adhesion, the adhesion mechanism should be understood fully and the appropriate technology for measuring adhesion is required. The adhesion is evaluated in terms of basic adhesion, thermodynamic adhesion energy and actual adhesion. As the widely used adhesion test technologies, the pull-off test and peel test methods show their unique superiority in dealing with a large number of samples and can be used to evaluate the adhesion performance of thin films qualitatively and semi-quantitatively.

Abstract:The cooling methods and key technologies used for infrared optical systems in three most advanced space infrared telescopes (SIRFT, ASTRO-F and WISE) in the world now are analyzed in detail. The importance of cooling technologies for space infrared optical systems and their trends are discussed. According to the analysis of the features and feasibility of different cooling methods, the necessity and feasibility to develop the cooling technologies for space infrared optical systems in China are indicated.

Abstract:The zoom lens theory and re-imaging theory of dual field-of-view infrared optical systems are presented. The focus length and space of each element in a lens group are solved according to the object-image exchanging rule in Gaussian imaging principle. The solving method for an initial structure of the double separate lens in a lens group is described in detail. The basic theory for solving with PW method is analyzed. Finally, an dual field-of-view infrared optical system based on a 320240 pixel cooled staring middle infrared focal plane array is designed according to the above theory. The optical system is evaluated in image quality with the optical modulation transfer function. The result shows that the design has a high image quality and can meet the requirements of practical applications.

Abstract:To obtain high quality InSb crystals, a precision diameter-constant control technology is required in the growth process of large size InSb crystals. The principle and method for controlling the diameter of a crystal during its growth by using the Czochralski Method are presented. The factors, such as temperature and time delay, which have influence on diameter-constant control are analyzed. The precision diameter-constant control is implemented by using a computer aided method in the growth process of large size InSb crystals. The resulting InSb crystal with a diameter of 3in shows its smooth surface from the shoulder. Its dislocation density is less than 10/cm^2.

Abstract:The causes of the stray radiation in an infrared optical system are analyzed according to different stray radiation sources. Some particular samples for restraining the stray radiation from mechanical and optical parts are listed. A method for choosing infrared coating is proposed. A Lyot stop is set up in a space infrared instrument and its suppression effectiveness for infrared stray radiation is evaluated in ground and in-orbit tests.

Abstract:The small infrared target detection methods used in the presence of background interference and noises are analyzed. A small infrared target detection algorithm combining temporal domain with spatial domain is put forward. First, the interference from background and noises is reduced by using conjoint frame subtraction because of the slow change of background. Then, the nonsubsampled Contourlet transform is implemented for the residual image so as to eliminate the residual background and noises and enhance the signal-to-noise ratio of the small targets. Finally, the enhanced image is processed by using the adaptive threshold and the small target is detected. The simulation result shows that compared with the small infrared target detection algorithm based on wavelet transform, this method can more precisely detect small infrared targets and has a higher detection effectiveness and a lower average false alarm rate.

Abstract:The zenith and azimuth angles of the surface cells of the earth are sampled uniformly. The position of a surface cell is transformed from the sphere reference frame into the earth equatorial reference frame. The geometric factors of earth radiation and earth's reflective radiation are calculated through numerical integration. The calculation result shows that this method is better than the random simulation method in calculation precision and efficiency and its data is in most agreement with that in the radiant exchange heat manual. It is very suitable for the calculation of the heat flux of a target.