Notes on the bunching peak of g(2) functions for correlated photons from single quantum dots

Second-order correlation functions for photon pulses associated with exciton-biexciton cascades are theoretically derived. A finite efficiency in photon detection and statistical distribution in exciton numbers are taken into account. It is found that the bunching peak height of photon statistics (g(2)(0)) depends on the mean number of excitons, N, and significant bunching is only detectable at very low excitation, N<<2.