New results for NbN phonon-cooled hot electron bolometric mixers above 1 THz

• Published in: IEEE transactions on applied superconductivity 1999-06, Vol.9 (2), p.4217-4220
• Main Authors: Gerecht, E., Musante, C.F., Jian, H., Yngvesson, K.S., Dickinson, J., Waldman, J., Yagoubov, P.A., Gol'tsman, G.N., Voronov, B.M., Gershenzon, E.M.
• Format: Article
• Language: English
• Subjects: Antennas; Bandwidth; Bolometers; Devices; Direct current; Electrons; Gas lasers; Hot electrons; Laser excitation; Laser noise; Lenses; Mixers; Noise level; Noise temperature; Optical coupling; Pump lasers; Receivers; Temperature
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/77.783955

NbN Hot Electron Bolometric (HEB) mixers have produced promising results in terms of DSB receiver noise temperature (2800 K at 1.56 THz). The LO source for these mixers is a gas laser pumped by a CO/sub 2/ laser and the device is quasi-optically coupled through an extended hemispherical lens and a self-complementary log-periodic toothed antenna. NbN HEBs do not require submicron dimensions, can be operated comfortably at 4.2 K or higher, and require LO power of about 100-500 nW. IF noise bandwidths of 5 GHz or greater have been demonstrated. The DC bias point is also not affected by thermal radiation at 300 K. Receiver noise temperatures below 1 THz are typically 450-600 K and are expected to gradually approach these levels above 1 THz as well. NbN HEB mixers thus are rapidly approaching the type of performance required of a rugged practical receiver for astronomy and remote sensing in the THz region.