Room temperature stable single-photon source

We report on the realization of a stable solid state room temperature source for single photons. It is based on the fluorescence of a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. Antibunching has been observed in the fluorescence light under both continuous and pulsed excitation. Our source delivers 2 x 10(1) s(-1) single-photon pulses at ail excitation repetition rate of 10 MHz. The number of two-photon pulses is reduced by a factor of five compared to strongly attenuated coherent sources.