The combined model operator in photodetection

The relation between the statistics of photons in input light on a detector and the measured photocounts is discussed for two types of light measurement, i.e., single photocount with one detector and coincidence detection with two detectors. The averages and variances of the measured photocounts are compared with the averages and variances of input photons on practical detectors having quantum efficiencies of /spl mu//sub 1/ and /spl mu//sub 2/. The calculations are carried out based on the combined operator model for a detector having less-than-unity quantum efficiency.