Low temperature diamond optomechanics*

Diamond optomechanical crystals (OMCs) are a promising architecture for studying mechanical motion in the quantum regime, since they enable interactions between phonons, photons, and the spin and orbital degrees of freedom of defect qubits such as nitrogen and silicon-vacancy centers, which can couple to mechanical motion via crystal strain. Recent experiments [1,2] have measured diamond OMCs at room temperature and shown [1] that these nanofabricated structures can host coherent nitrogen vacancy-center spins. However, an outstanding challenge to achieving quantum interactions in these systems is the demonstration of long-lived, high-strain mechanics near the ground state of motion. As a step toward this goal, we design and fabricate single-crystal diamond optomechanical crystals which host GHz-scale mechanical modes with large zero-point strain and characterize their optomechanical properties at 6K in a closed-cycle cryostat. We show optical and mechanical quality factors > 10⁵ and study the effects of optical absorption heating in these devices.
1. J. V. Cady, et al., Quantum Sci. Tech. 4 2 (2019)
2. M. J. Burek, et al., Optica 4 2 (2019) 3 12 (2016)