Superconducting Terahertz Sources with 12% Power Efficiency

Abstract

Low power efficiency is one of the main problems of terahertz (THz) sources, colloquially known as "the THz gap."In this work we present prototypes of THz devices based on whisker crystals of a high-temperature superconductor Bi2Sr2CaCu2O8+δ with a record high-radiation power efficiency of 12% at a frequency of approximately 4 THz. We employ various on- and off-chip detection techniques and, in particular, use the radiative cooling phenomenon for accurate evaluation of the emission power. We conclude that such devices can be used for creation of tunable, monochromatic, cw, compact, and power-efficient THz sources.