Stokes-parameter analysis of circular polarized terahertz waves from superconducting Josephson plasma emitter

We have been studying terahertz sources which consists of intrinsic Josephson junctions of high-Tc superconductors. In this paper, we report the helicity analysis of the circularly polarized terahertz source with a quarter-wave-plate of terahertz band. The right-handed circular polarization from the terahertz source is observed.