Compact High- Tc Superconducting Terahertz emitter operating up to 86 K

Single crystals of the high-temperature superconductor Bi${}_{2}$Sr${}_{2}$CaCu${}_{2}$O${}_{8}$ are promising terahertz emitters, but for operating temperatures above 70 K they either show no emission or radiate well below 500 GHz, limiting their applicability. To improve their emission properties, especially above liquid-nitrogen temperature, a standalone stack of overdoped material with high critical temperature and critical current density is embedded in a sandwich structure, for efficient heat removal. Emission of 0.577-THz light is achieved at 80 K, and the experimental results are compared to simulations based on three-dimensional coupled sine-Gordon equations plus heat-diffusion equations.