Superconducting cold-electron bolometer with proximity traps
Department of Physics, Chalmers University of Technology, S-41296, Gothenburg, Sweden
Available online 4 July 2003.
A novel concept of the superconducting cold-electron bolometer (SCEB) with proximity traps and SIN tunnel junctions for electron cooling has been proposed for optimal performance of the supersensitive detector. The THz signal is concentrated by superconducting antenna and absorbed by superconducting strip fabricated in the same layer. The released heat diffuses to normal metal traps provided by the proximity effect in superconductor due to direct contact with normal metal. The SIN tunnel junction formed by normal metal trap and another superconductor removes this heat very effectively due to small volume of the normal metal and approximately 100% efficiency (!) of tunnel junction as electronic cooler (relation of an area of the tunnel junction to the area of cooled absorber). A dc SQUID can be used as a readout system in a voltage-biased mode, collecting signal from both junctions in parallel. Theoretical estimations show that it is possible to realize high performance of the SCEB with NEP of 10-18 W/Hz1/2 at temperature 0.3 K with moderate volume of superconducting absorber and relatively small volume of normal metal traps less than 0.01 m3.
Author Keywords: Cold-electron bolometer; Normal metal trap; Tunnel junction; Electron cooling