PHYSICS AND APPLICATIONS OF HIGH-TC SUPERCONDUCTORS FOR INFRARED DETECTORS

Superconducting infrared detectors can be classified as thermal or photon, depending upon the detection mechanism. Superconducting transition edge microbolometers, which are thermal detectors, exploit the steep change in resistance with temperature at the transition temperature. Superconducting photon detectors include those based upon the non-equilibrium (Testardi) effect and those based upon photon-assisted tunnelling. Performance calculations for all three effects based upon the use of YBaCuO suggest high responsivity and detectivity; measurements are either lacking or else do not support the predictions. The principal application for the YBaCuO superconducting microbolometer is as a staring array in a thermal imaging (FLIR) system. The principal application for the non-equilibrium and photon-assisted tunnelling detectors is for very-long-wavelength detection of cold bodies in space.