Terahertz emission from a stack of intrinsic Josephson junctions in Pb-doped Bi₂Sr₂CaCu₂O_8+<i>δ</i>

Abstract

We observe continuous terahertz-wave emission from a stack of intrinsic Josephson junctions made of slightly Pb-doped Bi2Sr2CaCu2O. We investigate how Pb doping affects the c-axis current–voltage and emission characteristics. The terahertz emission spectra are measured by Fourier-transform infrared spectroscopy and reveal that the emission frequency is remarkably increased by Pb doping, an effect that we attribute to cavity resonance.