This paper discussed in detail some essentials on the Time Correlated Single Photon count technique (TCSP)

which includes principle of statistics

problems which should be noted in measurement and the estimation of basic technique.When the sample is excited

photon emission should satisfy the following conditions.(1) STABILITY: Time probabilities are fully the same in photon emission process

after the sample is excited.(2) PARTICULATE PROPERTY: Statistical distribution between neighbor excitations is irrelevant.(3) GENERALIZATION: Let (t) represent the probability of the emission of two photons in the range [0

t].Iflim (

t

)/

t

=0is satisfied

PT(k)

the probability of the emission of k photons in the interval T

is Poison distribution.