Generation of single colour centers by focussed nitrogen implantation
  Single defect centers in diamond have been generated via nitrogen implantation. The defects have been investigated by single defect center fluorescence microscopy. Optical and EPR spectra unambiguously show that the produced defect is the nitrogen-vacancy colour center. An analysis of the nitrogen flux together with a determination of the number of nitrogen-vacancy centers yields that on average two 2 MeV nitrogen atoms need to be implanted per defect center. 
J. Meijer, B. Burchard, M. Domhan, C.Wittmann, T.Gaebel, I.Popa, F.   Jelezko, and J. Wrachtrup