Development of Novel High Temperature Superconducting Detectors Based on Flux Activation and Ultrafast Dynamics.

摘要

It is proposed to study quasiparticle (QP) relaxation dynamics and flux mechanism of HTS using pump/probe femtosecond spectroscopy and nonequilibrium photoresponse in the presence of a magnetic field (and/or bias current). By adding a magnetic field, the number of vortices in a superconductor will be significantly increased. The first investigation will be to determine how quasiparticle-vortex interaction changes the QP relaxation process. The second investigation will be to study interactions of high energy quasiparticles and phonons with vortices, to understand the energy transfer mechanism from the electrons and phonons to vortices, and to determine vortex core excitation energy levels, as well as vortex motion (dissipation) time constant. The studies of QP relaxation dynamics and flux mechanism will help to determine the intrinsic speed limit of a superconducting detector, and help the construction of a sensitive flux activation detector.