  The nitrogen-vacancy (NV) center spin represents an appealing candidate for
quantum information processing. Besides the widely used microwave control, its
coherent manipulation may also be achieved using laser as mediated by the
excited energy levels. Nevertheless, the multiple levels of the excited state
of NV center spin make the coherent transition process become complex and may
affect the fidelity of coherent manipulation. Here, we adopt the strategy of
optimal quantum control to accelerate coherent state transfer in the ground
state manifold of NV center spin using laser. The results demonstrate improved
performance in both the speed and the fidelity of coherent state transfer which
will be useful for optical control of NV center spin in diamond.
