Efficient single photon sources based on nanodiamonds on a plasmonic platform

Abstract

We report on an efficient room-temperature source of single photons based on single nitrogen-vacancy centers in nanodiamonds (NDs) placing on a large-area plasmonic platform formed by crystalline gold flakes covered with a thin dielectric layer. Due to the strongly confined plasmonic fields in the thin dielectric layer, the NDs show a large enhancement in the fluorescence intensity without significant degradation in single photon purity. According to the deduced fluorescence lifetime from g((2)) measurements, the Purcell factor is estimated to be similar to 1.4. The plasmonic platform is very ideal for large-area fluorescence enhancement without the needs of sophisticated nanopositioning schemes for locating NDs at local hot spots in conventional plasmonic nanostructures.