Radiation line width in the Josephson effect

V. P. Koshelets, Pavel N. Dmitriev, Alexander S. Sobolev +6 more

Ch. Preis, Manas Sardar, J. Keller

V. A. Morozov

Takanari Kashiwagi, Takashi Yamamoto, Kazuya Ishida +8 more

Continuous electromagnetic waves in terahertz (THz) range have been observed from mesa structures of Bi2Sr2CaCu2O8+δ(Bi2212) single crystals^1) It has been established that the radiation frequency is determined by both the ac Josephson frequency and the resonance condition of the geometrical cavity^2). In order to understand the mechanism of the radiation from the intrinsic Josephson junctions (IJJs) in Bi2212, we studied the radiation line width and shape. These might depend upon the physical parameters of the Bi2212 single crystal such as the number of IJJs the fluctuations of the quasiparticles and pairs, the non-linearity and non-equilibrium conditions, and the stability of the electrical circuit including the IJJs. However, technical difficulties have been delayed the line width measurements in the THz range. Recently, we succeeded in measuring the radiation line width using a frequency mixer. These results will be compared to those from a single junction 1) L. Ozyuzer et al., Science 318 (2007) 1291., 2) K. Kadowaki et al., J. Phys. Soc. Jpn. 79 (2010) 023703

D. E. McCumber

Matteo Cirillo, I. Modena, P. Carelli +2 more

It is shown that a long Josephson junction (LJJ) fluxon oscillator can be used to generate radiation in the millimeter-wave region of the electromagnetic spectrum. The radiation emitted by the long junction is detected by a small-area planar junction coupled to the oscillator by means of superconducting integrated techniques.>