Fluctuation of photoelectrons and intensity correlation of light beams

Abstract

The complexity in writing down expressions for P (n, T), the probability that n electrons are ejected from a photodetector by a fluctuating incident light beam is discussed and the problem of computing coherence functions from a knowledge of the moments of n is solved by recasting the problem in terms of product densities familiar in stochastic point processes. A general method of arriving at P (n, T) from a knowledge of all the intensity correlations for any kind of light beam is studied. For the case of light from a thermal source with usual assumptions on the coherence functions P (n, T) is shown to be the Bose distribution.