An analysis of three dimensional radiation patterns from intrinsic Josephson junctions with hot spot

Abstract

In this study, we investigate numerically the terahertz radiation from the mesa-structured intrinsic Josephson junctions (IJJs). The Sine-Gordon equation for inside of the mesa, and the Maxwell equation for outside of the mesa, are solved simultaneously. We consider the influence of a hot spot in the mesa where jc locally decreases, and calculate the radiation power as a function of the voltage. We observe strong radiation when the ac Josephson frequency satisfies the cavity resonance condition. For this strong radiation from the IJJs mesa, we calculate the radiation patterns. The radiation patterns reflect the existence of two types of internal modes: a uniform background mode and a cavity resonance mode. Furthermore, the radiation patterns are strongly affected by the diffraction at substrate edges. © 2013 Elsevier Ltd. All rights reserved.