title: Cryocooled terahertz photoconductive detector system with background-limited performance in 1.5-4 THz frequency range.
abstract: We describe a 4-K-cryocooled dual-band terahertz (THz) photoconductive detector system with background-limited performance. The detector system comprises two THz photoconductive detectors covering a response in a wide frequency range from 1.5 to 4 THz, low noise amplifiers, optical low-pass filters to eliminate input radiation of higher frequencies, and a mechanical 4 K Gifford-McMahon refrigerator that provides practical and convenient operation without a liquid He container. The electrical and optical performances of the THz detector system were evaluated at a detector temperature of 4 K under 300 K background radiation. We proved that the detector system can achieve background-limited noise-equivalent-power on the order of 10(-14) W/Hz(1/2) in the frequency range from 1.5 to 4 THz even if the vibration noise of the mechanical refrigerator is present.
authors.affiliation: National Institute of Information and Communications Technology, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Aoki
authors.affiliation: Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011, Japan.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Hiromoto
mesh_terms: D004867:Equipment Design; D017785:Photons; D055618:Radiation Equipment and Supplies; D013696:Temperature; D055053:Terahertz Radiation