title: Optical dilution and feedback cooling of a gram-scale oscillator to 6.9 mK.
abstract: We report on the use of a radiation pressure induced restoring force, the optical spring effect, to optically dilute the mechanical damping of a 1 g suspended mirror, which is then cooled by active feedback (cold damping). Optical dilution relaxes the limit on cooling imposed by mechanical losses, allowing the oscillator mode to reach a minimum temperature of 6.9 mK, a factor of approximately 40 000 below the environmental temperature. A further advantage of the optical spring effect is that it can increase the number of oscillations before decoherence by several orders of magnitude. In the present experiment we infer an increase in the dynamical lifetime of the state by a factor of approximately 200.
authors.affiliation: LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Corbitt
authors.forename: Christopher
authors.initials: C
authors.lastname: Wipf
authors.forename: Timothy
authors.initials: T
authors.lastname: Bodiya
authors.forename: David
authors.initials: D
authors.lastname: Ottaway
authors.forename: Daniel
authors.initials: D
authors.lastname: Sigg
authors.forename: Nicolas
authors.initials: N
authors.lastname: Smith
authors.forename: Stanley
authors.initials: S
authors.lastname: Whitcomb
authors.forename: Nergis
authors.initials: N
authors.lastname: Mavalvala