Circuit Models of Simultaneously Biased Intrinsic Josephson Junction Stacks for Terahertz Radiations in High-Bias Regime

Experiment-based circuit models for Josephson plasma emitters (JPEs) made of cuprate superconductor Bi2Sr2CaCu2O8+delta single crystals are proposed. Introducing an LCR resonator shunting an RCSJ parallel circuit allows us to reproduce experimental radiation intensity as a function of device voltage. Mismatch in the resonance frequencies of the total device and the LCR part is related to the wide-range tuning of the radiation frequency of JPE. It is found that coupling capacitances for simultaneously biased operations provide significant increases in radiation intensities, which have been reported as synchronized radiation from multiple mesas in the literature.