Vibrational and electronic ultrafast relaxation of the nitrogen-vacancy   centers in diamond
  Two dimensional electronic spectroscopy and transient grating measurements were performed, for the first time, on nitrogen-vacancy centers in diamond. These measurements reveal energy transfer and vibrational pathways with consequences for spin coherence. 
V. M. Huxter, T. A. A. Oliver, D. Budker, and G. R. Fleming
cond-mat.mes-hall quant-ph