Coherent control of a nitrogen-vacancy center spin ensemble with a diamond mechanical resonator

Coherent control of the nitrogen-vacancy (NV) center in diamond’s triplet spin state has traditionally been accomplished with resonant ac magnetic fields. Here, we show that high-frequency stress resonant with the spin state splitting can also coherently control NV center spins. Because this mechanical drive is parity nonconserving, controlling spins with stress enables direct access to the magnetically forbidden j − 1i ↔ j 1i spin transition. Using a bulk-mode mechanical microresonator fabricated from single-crystal diamond, we apply intense ac stress to the diamond substrate and observe mechanically driven Rabi oscillations between the j − 1i and j 1i states of an NV center spin ensemble. Additionally, we measure the inhomogeneous spin dephasing time (T 2 ) of the spin ensemble within this f−1; 1g subspace using a mechanical Ramsey sequence and compare it to the dephasing times measured with a magnetic Ramsey sequence for each of the three spin qubit combinations available within the NV center ground state. These results demonstrate coherent control of a spin with a mechanical resonator and could lead to the creation of a phase-sensitive Δ-system inside the NV center ground state with potential applications in quantum optomechanics and metrology. © 2015 Optical Society of America