  Single silicon vacancy (SiV) color centers in diamond have recently shown the
ability for high brightness, narrow bandwidth, room temperature single photon
emission. This work develops a model describing the three level population
dynamics of single SiV centers in diamond nanocrystals on iridium surfaces
including an intensity dependent de-shelving process. Furthermore, we
investigate the brightness and photostability of single centers and find
maximum single photon rates of 6.2 Mcps under continuous excitation. We
investigate the collection efficiency of the fluorescence and estimate quantum
efficiencies of the SiV centers.
