Observation of strong coupling between a micromechanical resonator and an optical cavity field

TL;DR

This paper reports the first observation of strong coupling between a micromechanical resonator and an optical cavity field, demonstrating a key step towards quantum control of mechanical systems.

Contribution

It provides experimental evidence of optomechanical normal mode splitting, confirming strong coupling in a micromechanical and optical system, enabling quantum state manipulation.

Findings

Observation of optomechanical normal mode splitting

Evidence for strong coupling between cavity photons and mechanical resonator

Advancement towards quantum control of mechanical devices

Abstract

Achieving coherent quantum control over massive mechanical resonators is a current research goal. Nano- and micromechanical devices can be coupled to a variety of systems, for example to single electrons by electrostatic or magnetic coupling, and to photons by radiation pressure or optical dipole forces. So far, all such experiments have operated in a regime of weak coupling, in which reversible energy exchange between the mechanical device and its coupled partner is suppressed by fast decoherence of the individual systems to their local environments. Controlled quantum experiments are in principle not possible in such a regime, but instead require strong coupling. So far, this has been demonstrated only between microscopic quantum systems, such as atoms and photons (in the context of cavity quantum electrodynamics) or solid state qubits and photons. Strong coupling is an essential requirement for the preparation of mechanical quantum states, such as squeezed or entangled states, and also for using mechanical resonators in the context of quantum information processing, for example, as quantum transducers. Here we report the observation of optomechanical normal mode splitting, which provides unambiguous evidence for strong coupling of cavity photons to a mechanical resonator. This paves the way towards full quantum optical control of nano- and micromechanical devices.