Radiation power characterization and optimization of stack of intrinsic Josephson junctions

Terahertz radiation of the stack of intrinsic Josephson junctions in the mesa structure of the layered high T-c superconductors are characterized and presented in this work. The dependency of the radiated power to the geometrical parameters, cavity-waveguide boundaries and magnetic and electric bias has been investigated. This has been done by numerical calculation of the previously proposed coupled sine-Gordon equations, which characterize the electromagnetic dynamics of the stack of the intrinsic Josephson junctions. Using the obtained numerical results from these coupled equations, the effect of the design parameters such as dimensions of the mesa structure and the magnitude of the applied magnetic field and the dc current on the enhancement of the radiated power is studied. Thus, the power is optimized with respect to these considered parameters. By variation of the number of layers, which is corresponding to the number of equations in the system of the coupled sine-Gordon equations, we also investigate the effect of the number of intrinsic Josephson junctions on the total radiated power. The results from this part are also compared with the previous analytical models. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Guest Editors.