  We present the controlled creation of single nitrogen-vacancy (NV) centers
via ion implantation at the center of a photonic crystal cavity which is
fabricated in an ultrapure, single crystal diamond membrane. High-resolution
placement of NV centers is achieved using collimation of a 5keV-nitrogen ion
beam through a pierced tip of an atomic force microscope (AFM). We demonstrate
coupling of the implanted NV centers' broad band fluorescence to a cavity mode
and observe Purcell enhancement of the spontaneous emission. The results are in
good agreement with a master equation model for the cavity coupling.
