An investigation was made of  the spin dynamics of a nitrogen-vacancy center contained in an individual diamond nanocrystal in the presence of continuous microwave excitation. Upon periodic reversal of the microwave phase, a train of “Solomon echoes” was observed that effectively extended the system coherence lifetime to reach several tens of microseconds, depending on the microwave power and phase inversion rate. Starting from a model where the nitrogen-vacancy center interactedwith a bath of paramagnetic defects on the nanocrystal surface, average Hamiltonian theory was used to compute the signal envelope from its amplitude at the echo maxima. A comparison between the effective Rabi and Solomon propagators shows that the observed response can be understood as a form of higher-order decoupling from the spin bath.

Rotating Frame Spin Dynamics of a Nitrogen-Vacancy Center in a Diamond Nanocrystal. A.Laraoui, C.A.Meriles: Physical Review B, 2011, 84[16], 161403