QUANTUM DETECTORS IN SUPERCONDUCTING YBCO

A superconducting quantum detector structure in YBCO is described with a directly coupled SQUID read out circuit. The detector geometry is o ptimized for maximum photoresponse with the use of a serpentine patter n. The serpentine pattern reduces quasiparticle diffusion effects and maximizes the photoinduced changes in the kinetic inductance. The oper ation of this sensor is analyzed in terms of geometry and quasiparticl e lifetime to obtain expressions for the signal and noise of this dete ctor. The background limited infrared performance of this detector is calculated to be about 5x10(-17) NEP. The photoresponse is expected to be limited by the superconducting energy gap, about 30-40 mu m.