title: 0.43 THz emission from high-T(c) superconducting emitters optimized at 77 K.
abstract: A liquid helium-free, compact and continuous sub-terahertz radiation system operating at 77 K has been developed using a rectangular mesa device made from a high T(c)-superconducting Bi2Sr2CaCu2O(8+δ) single crystal, based on a different design of a stand-alone mesa sandwich structure to reduce the dc-current Joule heating effects. The mesa was thermally connected to sapphire plates through thin thermal grease embedded with diamond nano-crystals. When immersed in liquid N 2, the device emits intense radiation at 0.437 THz, the highest frequency ever achieved at 77 K, due to excitation of the TM(1, 0) rectangular cavity mode. By varying the dc current-voltage bias and the bath temperature in a He-flow cryostat, the device's emission frequency is broadly tunable from 0.31 THz at 79 K to 1.31 THz at 30 K.
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan. Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Minami
authors.forename: C
authors.initials: C
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Kashiwagi
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Kadowaki
authors.forename: R A
authors.initials: RA
authors.lastname: Klemm