Determination of signal-to-background ratio of single molecular photon source based on photon counting statistics

The real triggered single molecule source is recognized as an ideal single photon source with a Poissonian statistics background. By considering the effect of the triplet state in single molecule energy level, an explicit function is given for the signal-to-backgound ratio(SBR) by use of photon-counting statistics. When P-RS (1) much greater than2 rootP(RS) (2) - 3 P-RS (2), we present an efficient method to determine the SBR of the triggered single photons source, which shows SBR = P-RS(2) (1)/2 P-RS (2) An addition, the expression of Q, as a function of signal-to-backgound ratio, has been obtained. It turns out that this method is simpler and gives a greater accuracy than previous procedures.