Two-level ultrabright single photon emission from diamond nanocrystals

The fabrication of stable ultrabright single photon sources operating at room temperature is reported. The emitter is based on a color center within a diamond nanocrystal grown on a sapphire substrate by chemical vapor deposition method and exhibits a two-level electronic behavior with a maximum measured count rate of 3.2 x 10 6 counts/s at saturation. The emission is centered at ?756 nm with a full width at half-maximum ?11 nm and an excited state lifetime of 3.7 ns. These unique properties make it a leading candidate for quantum photonics and communication applications as well as for cellular biomarking