We investigate the fluorescence intensity correlation function of a single
CdSe quantum dot (QD) using a start-stop experiment. We observe strong phot
on antibunching, a signature of non-classical light emission, over a large
range of intensities (0.1-100 kW/cm(2)). The lack of coincidence at zero ti
me delay indicates a highly efficient Auger ionization process, which suppr
esses multi-photon emission in these colloidal QDs. Using careful analysis
of the saturation behavior of the coincidence histograms, the absorption cr
oss-section of a single QD has also been derived. (C) 2000 Elsevier Science
B.V. All rights reserved.