Evidence for a dual-source mechanism of terahertz radiation from rectangular mesas of single crystalline Bi_2Sr_2CaCu _2O_(8+δ)- intrinsic Josephson junctions

摘要

The THz radiation emitted from rectangular mesas of single-crystal Bi _2Sr_2CaCu_2O_(8+δ) was studied using angular distribution measurements and Fourier transform infrared spectroscopy. Unlike the recent theoretical predictions, the results provide strong evidence for a dual-source mechanism in which the uniform and non-uniform parts of the ac-Josephson current act as electric and magnetic current sources, respectively. The latter synchronizes with cavity modes of the mesa with integral harmonics of the fundamental radiation.