Applied Physics

Cooling Rays of Light

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Science  05 Jan 2007:
Vol. 315, Issue 5808, pp. 18
DOI: 10.1126/science.315.5808.18a

Just as the vibrational frequency of a mechanical oscillator shifts in response to changes in its environment (e.g., changes in the pressure, temperature, or viscosity of the medium in which it sits), so it may be expected that the radiation pressure exerted by light on an object can also affect the vibrational modes of mechanical resonators. This phenomenon opens the possibility of either amplifying (heating) or damping (cooling) the motion of the resonator with light. Whereas laser cooling is now routine for microscopic objects such as atoms, translating the technique to larger objects presents more of a challenge, because the dynamical back-action between the photons and the resonator requires that photon lifetimes be long enough to interact with the mechanical modes of the resonator. Effectively, the photons must be confined in the cavity on a time scale comparable to the mechanical oscillation period of the resonator. Four recent studies, by Schliesser et al., Gigan et al., Arcizet et al., and Kleckner and Bouwmeester, successfully access this regime for dynamical back-action and demonstrate efficient optical cooling of a mechanical oscillator mode to cryogenic temperatures. The ability to cool macroscopic objects with light not only has practical applications, as for mirror stabilization in large-scale interferometers, but also offers a means of probing quantum effects in mechanical systems. — ISO

Phys. Rev. Lett. 97, 243905 (2006); Nature 444, 67; 71; 75 (2006).

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