Tunable Amplification and Cooling of a Diamond Resonator with a Microscope

Control of the dynamics of mechanical resonators is central to quantum science and metrology applications. Optomechanical control of diamond resonators is attractive owing to the excellent physical properties of diamond and its ability to host electronic spins that can be coherently coupled to mechanical motion. Using a confocal microscope, we demonstrate tunable amplification and damping of the motion of a diamond nanomechanical resonator. Observation of both normal-mode cooling from room temperature to 80 K and amplification into self-oscillations with 60μW of optical power is observed via waveguide optomechanical readout. This system is promising for quantum spin optomechanics, as it is predicted to enable optical control of stress-spin coupling with rates of approximately 1 MHz (100 THz) to ground (excited) states of diamond nitrogen-vacancy centers.