Direct calibration of click-counting detectors
  We introduce and experimentally implement a method for the absolute detector calibration of photon-number-resolving time-bin multiplexing layouts based on the measured click statistics of superconduncting nanowire detectors. In particular, the quantum efficiencies, the dark count rates, and the positive operator-valued measures of these measurement schemes are directly obtained with high accuracy. The method is based on the moments of the click-counting statistics for coherent states with different coherent amplitudes. The strength of our analysis is that we can directly conclude -- on a quantitative basis -- that the detection strategy under study is well described by a linear response function for the light-matter interaction and that it is sensitive to the polarization of the incident light field. Moreover, our method is further extended to a two-mode detection scenario. Finally, we present possible applications for such well characterized detectors, such as sensing of atmospheric loss channels and phase sensitive measurements. 
Martin Bohmann, Regina Kruse, Jan Sperling, Christine Silberhorn, and   Werner Vogel
quant-ph