Single-crystal diamond low-dissipation cavity optomechanics

TL;DR

This paper demonstrates high-quality single-crystal diamond cavity optomechanical devices capable of room-temperature photon-phonon-spin coupling, with record low dissipation and high-frequency mechanical resonances suitable for quantum applications.

Contribution

The authors present the first realization of single-crystal diamond cavity optomechanical devices with record low dissipation and high-frequency resonances, enabling room-temperature quantum control of solid-state spins.

Findings

Mechanical resonances at 2 GHz with Q > 9000

Optomechanical cooperativity C ~ 3 achieved

Potential for strong coupling to diamond NV centers

Abstract

Single-crystal diamond cavity optomechanical devices are a promising example of a hybrid quantum system: by coupling mechanical resonances to both light and electron spins, they can enable new ways for photons to control solid state qubits. However, realizing cavity optomechanical devices from high quality diamond chips has been an outstanding challenge. Here we demonstrate single-crystal diamond cavity optomechanical devices that can enable photon-phonon-spin coupling. Cavity optomechanical coupling to $2\,\text{GHz}$ frequency ($f_\text{m}$) mechanical resonances is observed. In room temperature ambient conditions, these resonances have a record combination of low dissipation (mechanical quality factor, $Q_\text{m} > 9000$) and high frequency, with $Q_\text{m}\cdot f_\text{m} \sim 1.9\times10^{13}$ sufficient for room temperature single phonon coherence. The system exhibits high optical quality factor ($Q_\text{o} > 10^4$) resonances at infrared and visible wavelengths, is nearly sideband resolved, and exhibits optomechanical cooperativity $C\sim 3$. The devices' potential for optomechanical control of diamond electron spins is demonstrated through radiation pressure excitation of mechanical self-oscillations whose 31 pm amplitude is predicted to provide 0.6 MHz coupling rates to diamond nitrogen vacancy center ground state transitions (6 Hz / phonon), and $\sim10^5$ stronger coupling rates to excited state transitions.