Complementary to our efforts in diamond quantum photonics, we are exploring the interactions of diamond color centers with phonons in nanoscale mechanical devices. In contrast with light, mechanical vibrations can couple coherently to a variety of physical systems across microwave and optical domains, making them a promising solution to control and link quantum systems with optical and spin degrees of freedom. For example, engineering diamond devices that allow strong spin-phonon interactions could enable phonon-based interfaces between NV/SiV centers and other qubits at disparate energy scales.

Diamond NEMS cantilever arrays for color center-phonon coupling experiments

Recently, an increased understanding of the effect of lattice strain on the NV ground state spin sublevels, and the development of nanomechanical devices using our angled etching scheme, have enabled us to couple NV spins to the mechanical motion of diamond cantilevers [Phys. Rev. Applied  5, 034010 (2016)]. The use of nanoscale resonators boosts the spin-phonon interaction strength, and is essential to reach the strong spin-phonon coupling regime.

Diamond optomechanical crystals

Towards this goal, we have drawn from our ability to fabricate high quality-factor photonic crystal cavities in diamond to realize optomechanical crystals [arXiv:1512.04166], structures that confine both optical and mechanical resonances in a wavelength-scale volume. The interaction between light and mechanical vibrations in these devices allows driving and cooling of the mechanical mode by optical pumping. With this device platform, we hope to merge the rich field of cavity optomechanics with diamond quantum optics, and develop hybrid quantum systems that interface diamond spin qubits to telecom wavelength photons via phonons.