Quantum detectors in superconducting YBCO

Abstract

A superconducting quantum detector structure in YBCO is described with a directly coupled SQUID read out circuit. The detector geometry is optimized for maximum photoresponse, with the use of a serpentine pattem. The serpentine pattem reduces quasiparticle diffusion effects and maximizes the photoinduced changes in the kinetic inductance.The operation of this sensor is analyzed in terms of geometry and quasiparticle lifetime to obtain expressions for the signal and noise of this detector. The background limited infrared performance of this detector is calculated to be about 5~1 0 -l~ NEP. The photoresponse is expected to be limited by the superconducting energy gap, about 30-40lm.

Microwave detection using Josephson junction arrays integrated in a resonator

“…HTS junctions were proposed for application in various electromagnetic devices: frequency mixers, Josephson oscillators, standards of voltage, calibrators of direct current and so on [1,2]. The advantage of the proposed systems is that they require for cooling only inexpensive liquid nitrogen, not the expensive liquid helium.…”