PT Unknown AU Ryabchun, S Smirnov, A Pentin, I Vakhtomin, Y Smirnov, K Kaurova, N Voronov, B Goltsman, G TI Superconducting single photon detector integrated with optical cavity SE Proc. MLPLIT PY 2011 BP 143 EP 145 DE NbN SSPD; cavity ER