SUPERCONDUCTING QUANTUM DETECTORS

The discovery of high-temperature superconductors (HTS) spawned many p otential applications, including optical detectors. Realizing viable s uperconducting detectors requires achieving performance superior to co mpeting and more mature semiconductor detector technologies, and quant um detector technologies in particular. We review why quantum detector s are inherently more sensitive than thermal or bolometric detectors. This sensitivity advantage suggests that for operation at cryogenic te mperatures, we should be developing only quantum superconducting detec tors. Accordingly, we introduce and describe the structure and the ope ration of a superconducting quantum detector with a superconducting qu antum interference device (SQUID) readout circuit. The superconducting quantum detector, consisting of a superconducting loop, produces a ph otosignal in response to photoinduced changes in the superconducting c ondensate's kinetic inductance. The superconducting quantum detector i s designed to operate only in the superconducting state and not in the resistive or transition states.