Coupling of Nitrogen-Vacancy Centers to Photonic Crystal Cavities in   Monocrystalline Diamond
  The zero-phonon transition rate of a nitrogen-vacancy center is enhanced by a factor of ~70 by coupling to a photonic crystal resonator fabricated in monocrystalline diamond using standard semiconductor fabrication techniques. Photon correlation measurements on the spectrally filtered zero-phonon line show antibunching, a signature that the collected photoluminescence is emitted primarily by a single nitrogen-vacancy center. The linewidth of the coupled nitrogen-vacancy center and the spectral diffusion are characterized using high-resolution photoluminescence and photoluminescence excitation spectroscopy. 
Andrei Faraon, Charles Santori, Zhihong Huang, Victor M. Acosta,   Raymond G. Beausoleil
physics.optics quant-ph