We show that back-action noise in interferometric measurements such as gravitational-waves detectors can be completely suppressed by a local control of mirrors motion. An optomechanical sensor with an optimized measurement strategy is used to monitor mirror displacements. A feedback loop then eliminates radiation-pressure effects without adding noise. This very efficient technique leads to an increased sensitivity for the interferometric measurement, which becomes only limited by phase noise. Back-action cancellation is furthermore insensitive to losses in the interferometer.
@article{arxiv.gr-qc/0301068,
title = {Back-action cancellation in interferometers by quantum locking},
author = {J. -M. Courty and A. Heidmann and M. Pinard},
journal= {arXiv preprint arXiv:gr-qc/0301068},
year = {2010}
}