THz emission from a triangular mesa structure of Bi-2212 intrinsic Josephson junctions

Coherent, continuous and monochromatic terahertz electromagnetic waves were observed from the isosceles triangular mesa structures made of single crystalline high temperature superconductor Bi2Sr 2CaCu2O8+δ (Bi-2212) intrinsic Josephson junctions (IJJs), fabricated by the focus ion beam (FIB) technique. We studied experimentally the current-voltage (I-V) characteristics and the emission spectra by the FT-IR spectrometer in order to elucidate the radiation mechanism. The wide range of radiation frequency observed in the case of isosceles triangular mesa implies that the cavity resonance is not working properly but the ac-Josephson effect is working as a primary mechanism of THz radiation. © Published under licence by IOP Publishing Ltd