Using a nano-manipulation technique a nano-diamond with a single nitrogen vacancy center was placed directly on the surface of a gallium phosphide photonic crystal cavity. A Purcell-enhancement of the fluorescence emission at the zero phonon line by a factor of 12.1 was observed. The zero phonon line coupling was a first crucial step toward future diamond-based integrated quantum optical devices.

Enhancement of the Zero Phonon Line Emission from a Single Nitrogen Vacancy Center in a Nanodiamond Via Coupling to a Photonic Crystal Cavity. J.Wolters, A.W.Schell, G.Kewes, N.Nüsse, M.Schoengen, H.Döscher, T.Hannappel, B.Löchel, M.Barth, O.Benson: Applied Physics Letters, 2010, 97[14], 141108