  Quantum effects of radiation pressure are expected to limit the sensitivity
of second-generation gravitational-wave interferometers. Though ubiquitous,
such effects are so weak that they haven't been experimentally demonstrated
yet. Using a high-finesse optical cavity and a classical intensity noise, we
have demonstrated radiation-pressure induced correlations between two optical
beams sent into the same moving mirror cavity. Our scheme can be extended down
to the quantum level and has applications both in high-sensitivity measurements
and in quantum optics.
