Title :
A low-noise 2.5 THz superconductive Nb hot-electron mixer
Author :
Karasik, B.S. ; Gaidis, M.C. ; McGrath, W.R. ; Bumble, B. ; LeDuc, H.G.
Author_Institution :
Center for Space Microelectron. Technol., California Inst. of Technol., Pasadena, CA, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
We report on the development of a quasioptical Nb hot-electron bolometer mixer for a 2.5 THz heterodyne receiver. The devices are fabricated from a 12 nm thick Nb film, and have a 0.30 /spl mu/m/spl times/0.15 /spl mu/m in-plane size, thus exploiting diffusion as the electron cooling mechanism. The rf coupling was provided by a twin-slot planar antenna on an elliptical Si lens. A specially designed 2.5 THz system, using a CO/sub 2/-pumped FIR laser as local oscillator (LO), with rf hot/cold loads enclosed in vacuum to avoid atmospheric absorption, was used in the experiment. The experimentally measured double sideband (DSB) noise temperature of the receiver was as low as /spl les/3000 K, with an estimated mixer noise temperature of /spl ap/750 K. These results demonstrate the operation of the diffusion-cooled bolometer mixer above 2 THz.
Keywords :
bolometers; hot carriers; niobium; submillimetre wave mixers; submillimetre wave receivers; superconducting device noise; superconducting device testing; superconducting microbridges; superconducting microwave devices; 12 nm; 2.5 THz; CO/sub 2/-pumped FIR laser; Nb; Nb film; Si; diffusion electron cooling mechanism; double sideband noise temperature; elliptical Si lens; heterodyne receiver; in-plane size; local oscillator; microbridge; mixer noise temperature; quasioptical Nb hot-electron bolometer mixer; rf coupling; rf hot/cold loads; twin-slot planar antenna; Bolometers; Cooling; Electrons; Lenses; Niobium; Planar arrays; Superconducting device noise; Superconducting films; Superconductivity; Temperature;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
