Polarization analysis of terahertz emission from Bi-2212 cross-whisker intrinsic Josephson junction and its refractive index

Polarization analyses of the terahertz (THz) emission from Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ whisker crystals used for superconducting THz emitters were conducted. The THz emission mode was estimated by a simple polarization measurement, and a simulation study was conducted to examine the validity of the polarization analysis. The refractive index of whisker crystals revealed through the polarization analyses was greater than that of bulk single crystals and agreed well with our previous THz emission report. The simulation study suggested the complex plasma excitation mode of the THz emission, and an interpretation of the refractive index obtained in this study is provided.