Macroscopic mechanical oscillators at the quantum limit through optomechanical cooling

We discuss ways in which the optomechanical coupling provided by radiation pressure can be used to cool macroscopic collective degrees of freedom such as the vibrational modes of movable mirrors. Cooling is achieved with a phase-sensitive feedback loop that effectively overdamps a mirror’s motion without increasing the thermal noise. The feedback that results can bring macroscopic objects down to the quantum limit. In particular, it is possible to achieve squeezing and entanglement.