Toward diamond spin-optomechanical systems in the quantum regime

Engineering strong interactions between spins in the solid state is an outstanding challenge. One class of approaches to this problem involves circumventing the native but weak and distance-dependent magnetic dipolar interaction by introducing an intermediary quantum system. A promising candidate for this role is a mechanical resonator, which can be coupled strongly to a wide range of quantum systems while maintaining long phonon lifetimes, including solid state spins via lattice strain. For silicon vacancy (SiV) centers in diamond, this spin-phonon interaction is predicted to be very high (> 1 MHz). To harness this large susceptibility to strain, we fabricate high-Q optomechanical crystals (OMCs) in SiV-containing diamond and use light to control the motion of a GHz-frequency mechanical mode. We find that optomechanical cooling of the mode to its quantum ground state is affected by photon absorption-induced heating but robust in comparison to silicon OMCs, and describe ongoing work towards ground state operation of diamond OMCs and high-cooperativity SiV-phonon interactions.