QUASI-OPTICAL SUPERCONDUCTING HOT-ELECTRON BOLOMETER FOR SUBMILLIMETER WAVES

We report on a superconducting hot electron bolometer coupled to radia tion via a broadband antenna. The bolometer, a structured NbN film, wa s patterned on a thin dielectric membrane between terminals of a gold slotline antenna. We investigated the response to submillimeter radiat ion (wave-lengths similar to 0.1 mm to 0.7 mm) in the fundamental Gaus sian mode. We found that the directivity of the antenna was constant w ithin a factor of 2.5 through the whole experimental range. The noise equivalent power of the bolometer at 119 mu m was similar to 3 . 10(-1 3) W/HZ(1/2); a time constant of similar to 160 ps was estimated.