Coherent terahertz emission of intrinsic Josephson junction stacks in the hot spot regime [corrected].
We report on THz emission measurements and low temperature scanning laser imaging of Bi2Sr2CaCu2O8 intrinsic Josephson junction stacks. Coherent emission is observed at large dc input power, where a hot spot and a standing wave, formed in the "cold" part of the stack, coexist. By changing bias current and bath temperature, the emission frequency can be varied by more than 40%; the variation matches the Josephson-frequency variation with voltage. The linewidth of radiation is much smaller than expected from a purely cavity-induced synchronization. Thus, an additional mechanism seems to play a role. Some scenarios, related to the presence of the hot spot, are discussed.
Wang
H B
HB
National Institute for Materials Science, Tsukuba 3050047, Japan.
Guénon
S
S
Gross
B
B
Yuan
J
J
Jiang
Z G
ZG
Zhong
Y Y
YY
Grünzweig
M
M
Iishi
A
A
Wu
P H
PH
Hatano
T
T
Koelle
D
D
Kleiner
R
R