夜视像增强器(蓝光延伸与近红外延伸光阴极)的近期进展

Recent developments of night vision image intensifiers (extended blue and extended near infrared photocathodes)

２０世纪９０年代以来，夜视像增强器的研究主要朝着两个方向发展：一是研究对于探测、识别与确认沙漠地带或沙地景物有贡献的蓝光延伸（＜５５０ｎｍ）ＧａＡｓ负电子亲和势（ＮＥＡ）光阴极，光谱响应向短波长延伸，使光阴极灵敏度、光增益与鉴别率等性能大大优于标准三代管，从而形成“加强三代管”或所谓“四代管”，其探测性能较标准三代管高一倍；二是研究与夜天空辐射较为匹配、对１．０６μｍ激光有较高响应的光阴极，包括研究ＩｎＧａＡｓ、ＮＥＡ光阴极（１．０～１．３μｍ和１．５～２．０μｍ）和多碱光阴极（１．０～１．１μｍ）这三类近红外（ＮＩＲ）像管，可用于主被动夜视。本文综述了这几个方面的进展及其在夜视中的实际应用。

Since 1990s, study of night vision image intensifiers turns towards to two directions. The first one is to investigate the negative electron affinity (NEA) photocathode of third generation night viewing devices by extending the spectral reponse into blue (less than 550nm) region of electromagnetic spectrum, in which the contribution in the blue response of the image intensifier significantly increases detection, recognition and identification of targets in sandy or desert terrain. The enhanced third generation image intensifier has double the spectral sensitivity, luminous gain and resolution of standard third generation image intensifiers; and at starlight conditions the enhanced third generation image intensifier has double the imaging performance than the standard third generation image intensifiers. The second one is to develop the extended near infrared (NIR) image intensifiers with InGaAs semiconductor based photocathodes having 1 0～1 3μm and 1 5～2 0μm spectral sensitivities, and multi alkali based photocathode having 1 0～1 1μm spectral sensitivities. The important field performance of such extended NIR image intensifiers will have active and passive imaging, which is the ability of the system to clearly image a scene at low light levels, and the ability of the system to detect laser illumination used for target acquisition or designation and range finding. The present paper gives an overview of the achivements and developments in these two image intensifier fields in Litton Electron Devices Division/Garland Operation, and their practical applications in night vision surveillance.