Direct Measurement of the Photon Statistics of a Triggered Single Photon   Source
  We studied intensity fluctuations of a single photon source relying on the pulsed excitation of the fluorescence of a single molecule at room temperature. We directly measured the Mandel parameter Q(T) over 4 orders of magnitude of observation timescale T, by recording every photocount. On timescale of a few excitation periods, subpoissonian statistics is clearly observed and the probablility of two-photons events is 10 times smaller than Poissonian pulses. On longer times, blinking in the fluorescence, due to the molecular triplet state, produces an excess of noise. 
F. Treussart, R. Alleaume, V. Le Floc'h, L.T. Xiao, J.-M Courty, and   J.-F. Roch