Quantum Optics Colloquium by Andreas Nunnenkamp

Quantum science and technology with cavity optomechanics

Cavity optomechanics is a rapidly-growing field in which mechanical degrees of freedom are coupled to modes of the electromagnetic field inside optical or microwave resonators. Adapting laser-cooling techniques from atomic physics several experiments have recently observed mechanical motion close to the quantum ground-state. This paves the way to exploit these systems for the engineering of phonon and photons at the nanoscale with exciting, novel applications for science and technology [Phys. Today 65, 29 (2012), Rev. Mod. Phys. 86, 1391 (2014)].

Along this line of thought, I will give an overview of recent research highlights and an outline of future directions. First, I will show that feedback of homodyne measurements can be used to suppress thermal and back-action noise and increase sideband asymmetry. As the feedback gain is increased, the back-action from the amplified vacuum fluctuations will eventually limit the cooling efficiency and reduce the sideband asymmetry [arXiv:1602.05942]. I will then report on the realization of the so-called reversed dissipation regime of cavity optomechanics [arXiv:1602.05180] in which dissipation of the mechanical oscillator dominates over that of the electromagnetic modes [PRL 113, 023604 (2014)]. Finally, I will discuss synchronization in the simple quantum-mechanical scenario of one harmonic self-oscillator [PRL 112, 094102 (2014)] as well as one nonlinear self-oscillator [arXiv:1603.01409] coupled to an external drive.