HOTEYE: A novel thermal camera using higher operating temperature infrared detectors

Conventional high performance infrared (IR) sensors need to be cooled to around 80K in order to achieve a high level of thermal sensitivity. Cooling to this temperature requires the use of Joule-Thomson coolers (with bottled gas supply) or Stirling cycle cooling engines, both of which are bulky, expensive and can have low reliability. In contrast to this, higher operating temperature (HOT) detectors are designed to give high thermal performance at an operating temperature in the range 200K to 240K. These detectors are fabricated from multi-layer mercury cadmium telluride (MCT) structures that have been designed for this application. At higher temperatures, lower cost, smaller, lighter and more reliable thermoelectric (or Peltier) devices can be used to cool the detectors. The HOTEYE thermal imaging camera, which is based on a 320x256 pixel HOT focal plane array, is described in this paper and performance measurements reported.