Toward terahertz heterodyne detection with superconducting Josephson   nano-junctions
  In this letter, we present the study of the high-frequency mixing properties of ion irradiated YBa2Cu3O7 Josephson nano-junctions. The frequency range, spanning above and below the characteristic frequencies fc of the junctions, permits clear observation of the transition between two mixing regimes. The experimental conversion gain was found to be in good agreement with the prediction of the three ports model. Finally, we discuss the potential of the junctions to build a Josephson mixer operating in the terahertz frequency range. 
A. Luo, T. Wolf, Y. Wang, M. Malnou, C. Ulysse, G. Faini, P. Febvre,   J. Lesueur, N. Bergeal
cond-mat.supr-con