Highly efficient triggered emission of single photons by colloidal CdSe∕ZnS nanocrystals

Abstract

We demonstrate the realization of a highly efficient triggered source of single photons emitted by colloidal CdSe∕ZnS nanocrystals at room temperature. Under pulsed excitation, the fluorescence of single nanocrystals excited close to saturation exhibits a perfect antibunching and the probability to detect a single emitted photon per excitation pulse reaches 3%, comparable to the best values reported for other emitters. Without any correction, the probability of simultaneously emitting two photons is 25 times lower than for a faint pulsed laser. Combined with recent reports on the reduction of fluorescence intermittency, these results indicate that CdSe∕ZnS nanocrystals are promising single-photon sources.