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Extending the Coherence Lifetime of Nitrogen Vacancy Centers in Diamond

(A) Magnetic field orientation with respect to NV quantization axis. (B) T2 enhancement as a function of field orientation (C) Two fold enhancement of T2 relaxation.

Scientific Achievement
Suppressed the decoherence of ensemble of nitrogen-vacancy (NV) centers by a factor of 2, with a potential enhancement of up to 60 times

Significance and Impact
This technique can be applied to ensemble NV spin systems to enhance the magnetic field sensitivity of the NV centers, and also to improve the figure of merit for use in quantum computing.

This work, conducted in the NMR group at MSD, reports sensitive detection of the nuclear quadrupolar interaction of the 14N nuclear spin of the nitrogen-vacancy (NV) center using the electron spin-echo envelope modulation technique. A weak transverse magnetic field was applied to the spin system so that certain forbidden transitions became weakly allowed due to second-order effects involving the nonsecular terms of the hyperfine interaction. The weak transitions cause modulation of the electron spin-echo signal, and a theoretical analysis suggests that the modulation frequency is primarily determined by the nuclear quadrupolar frequency; numerical simulations confirm the analytical results and show excellent quantitative agreement with experiments. This is an experimentally simple method of detecting quadrupolar interactions, and it can be used to study spin systems with an energy structure similar to that of the NV center.

C. S. Shin et al. Phys. Rev. B 88 (2013) doi:10.1103/PhysRevB.88.161412