A high-speed, MWIR reference source for FPA non-uniformity correction using negative luminescence

摘要

We have previously discussed the potential of using a Hg_(1-x)Cd_xTe source as a reference plane for the non-uniformity correction of thermal imagers and which is being developed as an option for the UK 3rd generation, high performance thermal imaging program (Albion). In this paper we will present our first results on a large area (1.5 cm × 1.5 cm) source which was grown on a silicon substrate and can simulate a range of temperatures from -10 °C to +30 °C. Due to the fast switching speed, the apparent temperature can be changed on a frame by frame basis. Also, the operation of the device can be synchronized to the integration time of the camera to reduce the mean power requirements by a factor of 10 and reduce thermal heating effects. The main applications for Hg_(1-x)Cd_xTe devices as high-performance, cryogenically-cooled detectors typically require very low drive currents. The use of this material for large-area LEDs has generated new challenges to deal with the high peak currents. These are typically in the range 1-2 A/cm~2 for a MWIR waveband source and have led to a need to reduce the common impedance, reduce the contact resistances and consider the effects of current crowding.