Diamond optomechanical crystals with embedded nitrogen-vacancy centers*

Hybrid mechanical systems, in which qubits are coupled to mechanical degrees of freedom, have recently emerged as a promising alternative and supplement to traditonal photonic systems. Recent experiments¹ have demonstrated such a hybrid system with diamond mechanical resonators and embedded nitrogen-vacancy (NV) centers, which interact with one another via crystal strain. While previously realized devices have enabled, for example, extension of coherence using mechanically-dressed spin states and frequency and polarization tuning of the NV center excited state transition, NV-phonon coupling rates have not approached the high quantum cooperativity regime necessary for such applications as phonon-mediated spin-spin interactions and NV-assisted mechanical cooling. As a preliminary step toward the high cooperativity regime in NV center-based hybrid mechanical devices, we design and fabricate single-crystal diamond optomechanical crystals (OMCs), which host GHz-scale mechanical modes and telecom-band optical modes and contain embedded NV centers. Importantly, the spin coherence of these NV centers has been preserved through the fabrication process, with T₂^* exceeding 1 μs and T₂ exceeding 70 μs.
1. D. Lee, et al., J. Opt. 19 033001 (2017)