Single photon emission from a single molecule

Photon emission from a single molecule at room temperature exhibits nonclassical features. Continuous wave fluorescence excitation provides antibunching in the emitted photons sequence as a signature of the property to only emit one photon at a time. A short pulsed excitation can then produce single photons on demand, with an overall quantum efficiency up to 4.5% in our experimental setup. Direct measurement of the Mandel parameter Q(T) for an observation period of duration T follows a subpoissonian statistics on short time scale and superpoissonian statistics on longer time scale. The latter is attributed to blinking in the fluorescence due to the occurence of a metastable molecular triplet state. To cite this article: F. Treussart et al., C. R. Physique 3 (2002) 501–508.