Dynamics of the non-classical light from a single solid-state quantum   emitter
  We measure the dynamics of a non-classical optical field using two-time second-order correlations in conjunction with pulsed excitation. The technique quantifies single-photon purity and coherence during the excitation-decay cycle of an emitter, illustrated here using a quantum dot. We observe that for certain pump wavelengths, photons detected early in the cycle have reduced single-photon purity and coherence compared to those detected later. A model indicates that the single-photon purity dynamics are due to exciton recapture after initial emission and within the same pulse cycle. 
Edward B. Flagg, Sergey V. Polyakov, Tim Thomay, Glenn S. Solomon
quant-ph