Quantum-enhanced micro-mechanical displacement sensitivity

TL;DR

This paper demonstrates that using squeezed light in microcavity optomechanics can enhance displacement measurement sensitivity beyond shot noise limits, marking a novel application in quantum sensing.

Contribution

It introduces the first experimental use of squeezed light to improve mechanical transduction sensitivity in microcavities, achieving sub-shot noise measurement.

Findings

Sensitivity improved by -0.72 dB below shot noise

Successful implementation of phase squeezed vacuum states

Enhanced measurement precision in microcavity optomechanics

Abstract

We report on a hitherto unexplored application of squeezed light: for quantum-enhancement of mechanical transduction sensitivity in microcavity optomechanics. Using a toroidal silica microcavity, we experimentally demonstrate measurement of the transduced phase modulation signal with a sensitivity $-0.72(\pm 0.01)$\,dB below the shot noise level. This is achieved for resonant probing in the highly under-coupled regime, by preparing the probe in a weak coherent state with phase squeezed vacuum states at sideband frequencies.