Abstract-Imaging of local temperature distributions in mesas of high-Tc superconducting terahertz sources

M Tsujimoto, H Kambara, Y Maeda, Y Yoshioka, Y Nakagawa and I Kakeya

http://iopscience.iop.org/1742-6596/568/2/022048

tsujimoto@sk.kuee.kyoto-u.ac.jp

Department of Electronic Science and Engineering, Kyoto University, Kyoto, Japan 

Stacks of intrinsic Josephson junctions in high-Tc superconductors are a promising source of intense, continuous, and monochromatic terahertz waves. In this paer, we establish a fluorescence-based temperature imaging system to directly image the surface temperature on a Bi2Sr2CaCu2O8+δ mesa sample. Intense terahertz emissions are observed in both high- and low-bias regimes, where the mesa voltage satisfies the cavity resonance condition. In the high- bias regime, the temperature distributions are shown to be inhomogeneous with a considerable temperature rise. In contrast, in the low-bias regime, the distributions are rather uniform and the local temperature is close to the bath temperature over the entire sample.