Ultrafast coherent optical control of a single diamond spin

As an optically addressable solid-state electronic spin, the nitrogen-vacancy (NV) center in diamond has great promise for applications in quantum information science and metrology. At temperatures below $\approx 10$ K, the NV center's optical fine structure facilitates coherent coupling between the electronic spin and light, providing the means for all-optical spin control and other applications in quantum optics. Here, using ultrafast optical pump-probe techniques, we investigate the interplay of orbital, vibrational, and spin dynamics on timescales ranging from femtoseconds to nanoseconds. These techniques provide a flexible and powerful probe of orbital dynamics in the NV center's optically excited state, and enable optical spin control with sub-picosecond resolution.