Strong coupling of an optomechanical system to an anomalously dispersive atomic medium

TL;DR

This paper explores a hybrid optomechanical system where atomic coherence and anomalous dispersion enhance radiation pressure, enabling ground-state cooling and improved displacement measurement at low photon numbers.

Contribution

It demonstrates how atomic coherence and anomalous dispersion can significantly enhance optomechanical interactions, enabling strong coupling and quantum state generation at low photon levels.

Findings

Enhanced optomechanical coupling via atomic coherence.

Ground-state cooling at room temperature.

Improved displacement measurement sensitivity.

Abstract

We investigate a hybrid optomechanical system in which a membrane oscillator is coupled to a collective spin of ground states of an intracavity $\Lambda$-type three-level atomic medium. The cavity field response is greatly modified by atomic coherence and the anomalous dispersion generated by two Raman pumping beams near two-photon resonance. The optomechanical interaction, therefore radiation pressure force, is substantially enhanced due to superluminal propagation of photons in the cavity. Such improvement facilitates ground-state cooling of the mechanical oscillator with room temperature thermal environment. Moreover, it can greatly improve the sensitivity and bandwidth of displacement measurement. In such system, optically-controlled strong-coupling interaction between the mechanical oscillator and cavity field could be implemented on small intracavity photon number, even at the single quanta level, which is important for weak-light nonlinear photonics and the generation of nonclassical quantum states in the mechanical field.