Coupling of nitrogen-vacancy centers in diamond to a GaP waveguide
  The optical coupling of guided modes in a GaP waveguide to nitrogen-vacancy (NV) centers in diamond is demonstrated. The electric field penetration into diamond and the loss of the guided mode are measured. The results indicate that the GaP-diamond system could be useful for realizing coupled microcavity-NV devices for quantum information processing in diamond. 
K.-M.C. Fu, C. Santori, P.E. Barclay, I. Aharonovich, S. Prawer, N.   Meyer, A. M. Holm, and R.G. Beausoleil