“Non-Josephson” radiation from Josephson tunnel junctions

Vito Francis Russo

Daniel N. Rogovin, Marlan O. Scully, Patrick A. Lee

É. M. Belenov, Сергей Иванович Веденеев, E. M. Golyamina

Indirect observations are reported of stimulated emission of electromagnetic radiation by superconducting Josephson tunnel junctions or microbridges in such junctions exhibiting the properties of a strip resonator. Excitation in the resonator of a field of frequency ω by Josephson radiation of frequency ωJ = 2ω gave rise to a current step in the current-voltage characteristics of Nb–oxide–Pb tunnel junctions and this step indicated that lasing occurred at the frequency ω.

Tetsuo Ogawa, 小川 哲生

Matteo Cirillo, I. Modena, Fortunato Santucci +3 more

We have measured the Josephson radiation emitted at millimeter-wave frequencies by a long Josephson junction dc-current biased on Fiske steps of the current-voltage characteristic. Our measurements demonstrate that differences between dynamic excitation generating Fiske steps and fluxon oscillations giving rise to zero-field steps in long junctions may exist. The radiation, whose maximum measured frequency is 240 GHz, is generated by an in-line junction and detected on a chip by a small planar tunnel junction. From measurements of Shapiro steps amplitude and photon-assisted tunneling steps we find that the coupled radiation has a power tunability of 350 nW and the maximum coupled power is 20 nW in a 30-Ω normal-state resistance tunnel junction.

L. A. Zil'Berman