Study of coherent and continuous terahertz wave emission in equilateral triangular mesas of superconducting Bi_2Sr_2CaCu _2O_(8+δ) intrinsic Josephson junctions

摘要

We report on intense and coherent terahertz (THz) electromagnetic (EM) waves emitted from equilateral triangular mesa structures of the intrinsic Josephson junctions (IJJs) in single crystalline high-T_c superconducting Bi_2Sr_2CaCu_2O _(8+δ). The focused ion beam milling technique is used for mesa fabrication. THz radiation is observed when the emission frequency is in the vicinity of the primary cavity resonance frequency determined by the mesa geometry. We also investigated numerically the THz radiation from such mesas using the finite difference time domain method. We found an apparent EM mode similar to the known TM(1, 0) = TM(0, 1) cavity mode during the THz emission.