MEASUREMENT OF THE CURRENT-DENSITY DISTRIBUTION IN HIGH-TEMPERATURE SUPERCONDUCTING MICROSTRIP BY MEANS OF KINETIC-INDUCTANCE PHOTORESPONSE

We report a technique for measuring the spatial profile of microwave-f requency currents in resonant thin-film superconducting microstrip dev ices operated near resonance. We probe the patterned superconducting d evice as a function of position by scanning a modulated light beam acr oss the region to be probed. With the light focused to a spot size muc h smaller than the microstrip width, we have measured the current dens ity distribution as a function of position across the width of the str ip. Using an elementary model for the superconducting current density distribution, we fit an effective penetration depth at the edge of the microstrip. (C) 1993 John Wiley & Sons, Inc.