Heterodyne spectroscopy with superconducting single-photon detector Yu.V. Lobanov, M.L. Shcherbatenko, A.V. Semenov, V.V. Kovalyuk, A.A. Korneev and G.N. Goltsman EPJ Web Conf., 132 (2017) 01005 Published online: 13 December 2016 DOI: 10.1051/epjconf/201713201005