Observation of back-action cancellation in interferometric and weak force measurements

TL;DR

This paper reports the first experimental demonstration of back-action noise cancellation in optical measurements, significantly enhancing sensitivity in displacement and force detection through destructive interference.

Contribution

The authors experimentally demonstrate back-action cancellation in an optical cavity, advancing quantum measurement techniques for ultra-sensitive displacement and force sensing.

Findings

Back-action noise was canceled via destructive interference.

Sensitivity improved by a factor greater than 20.

First experimental observation of back-action cancellation in this context.

Abstract

We experimentally demonstrate a cancellation of back-action noise in optical measurements. Back-action cancellation was first proposed within the framework of gravitational-wave detection by dual resonators as a way to drastically improve their sensitivity. We have developed an experiment based on a high-finesse Fabry-Perot cavity to study radiation-pressure effects in ultra-sensitive displacement measurements. Using an intensity-modulated intracavity field to mimic the quantum radiation-pressure noise, we report the first observation of back-action cancellation due to a destructive interference between radiation-pressure effects on both mirrors of the cavity. We have observed a sensitivity improvement by a factor larger than 20 both in displacement and weak force measurements.