Superconducting Photomultiplier: High Sensitivity Detection

JOSEPHSON JUNCTION PHOTOMULTIPLIER NIOBIUM TUNNEL JUNCTION HYPRES UTILIZES A THIN, OPTICALLY SENSITIVE, MULTILAYER SUPERCONDUCTING FILM WHICH FORMS ONE ELECTRODE OF A JOSEPHSON JUNCTION USED FOR DETECTING ULTRA-VIOLET, OPTICAL AND INFRARED RADIATION. THE SUPERCONDUCTING PHOTOMULTIPLIER, A FUNDAMENTAL ADVANCE BEYOND JUNCTION DETECTORS, EMPLOYS A SEPARATELY OPTIMIZED DETECTING LAYER, MATED WITH A HIGH QUALITY NIOBIUM AMPLIFYING JUNCTION. IT WILL PROVIDE SUBNANOSECOND OPTICAL RESPONSE, ULTRA-LOW NOISE AND HIGH RESPONSIVITY FROM UV THROUGH THE INFRARED. HYPRES HAS ALREADY FABRICATED THE KEY ELEMENT, A NIOBIUM NITRIDE LAYER OVER A NIOBIUM TUNNEL JUNCTION, AS WELL AS YBCO FILM AND NIOBIUM TUNNEL JUNCTIONS ON THE SAME SUBSTRATE. THE GAIN OF SUCH DEVICES IS ESTIMATED TO BE IN EXCESS OF 100. THIS TECHNOLOGY ALLOWS COMBINING SUPERCONDUCTIVE SIGNAL PROCESSING CIRCUITS WITH OPTICAL RECEIVERS AND ACTIVE AND PASSIVE FOCAL PLANE ARRAYS.