We propose an approach to control the polarization of terahertz (THz) radiation from intrinsic Josephson-junction stacks in single crystalline high-temperature superconductor Bi2Sr2CaCu2O8+δ. By monolithically controlling the surface current distributions in the truncated square mesa structure, we can modulate the polarization of the emitted THz wave as a result of two orthogonal fundamental modes excited inside the mesa. Highly polarized circular terahertz waves with a degree of circular polarization of more than 99% can be generated using an electrically controlled method. The emitted radiation has a high intensity and a low axial ratio (AR<1 dB). The intuitive results obtained from the numerical simulation based on the conventional antenna theory are consistent with the observed emission characteristics.
@article{arxiv.1711.01375,
title = {Monolithic superconducting emitter of tunable circularly polarized terahertz radiation},
author = {A. Elarabi and Y. Yoshioka and M. Tsujimoto and I. Kakeya},
journal= {arXiv preprint arXiv:1711.01375},
year = {2018}
}