Dynamic control of temperature distributions in stacks of intrinsic josephson junctions in Bi2Sr2CaCu2 O8 +δ for intense terahertz radiation

Abstract

We study the universal relationship between the hot-spot size and the intensity of terahertz emission from intrinsic Josephson junctions by dynamically controlling the temperature distributions in mesas of Bi2Sr2CaCu2O8+δ. The uniform current bias leads to a significant increase in local temperature compared to the nonuniform current bias. The thermal response of emission differs between the high- and low-bias regimes. We find a strong positive correlation between the emission intensity and the volume of the superconducting parts in the emitting stack. We identify the remarkable increase in the emission intensity by up to 20% by eliminating the excess Joule heat from the mesa.