Authors: Hancong Sun, Raphael Wieland,Zuyu Xu, Zaidong Qi, Yangyang Lv, Ya Huang, Huili Zhang, Xianjing Zhou, Jun Li, Yonglei Wang, Fabian Rudau, Johannes S. Hampp, Dieter Koelle, Shigeyuki Ishida, Hiroshi Eisaki, Yoshiyuki Yoshida, Biaobing Jin, Valery P. Koshelets, Reinhold Kleiner, Huabing Wang,and Peiheng Wu
Physical Review Applied 10, 024041 (2018)
We report on a Stirling-cooled compact Bi2Sr2CaCu2O8+δ intrinsic Josephson-junction stack with very high critical current density and improved cooling, operating at bath temperatures Tb up to 86 K. The square stand-alone stack is embedded between two sapphire substrates. For bath temperatures between 27.8 and 86 K emission is observed at frequencies from 0.356 to 2.09 THz. The emission power exceeds 1 μW at bath temperatures between 60 and 80 K for emission frequencies between 0.5 and 0.88 THz. A record high value of 0.577 THz is obtained for the emission frequency at Tb =80 K, which is important for potential applications using liquid nitrogen as a coolant. We also compare our experimental results with numerical simulations based on three-dimensional coupled sine-Gordon equations combined with heat diﬀusion equations.