Mechanical Oscillation and Cooling Actuated by the Optical Gradient Force
In this work, we combine the large per-photon optical gradient force with the sensitive feedback of a high quality factor whispering-gallery microcavity. The cavity geometry, consisting of a pair of silica disks separated by a nanoscale gap, shows extremely strong dynamical backaction, powerful enough to excite coherent oscillations even under heavily damped conditions (mechanical Q≈4). In vacuum, the threshold for regenerative mechanical oscillation is lowered to an optical input power of only 270 nW, or roughly 1000 stored cavity photons, and efficient cooling of the mechanical motion is obtained with a temperature compression factor of nearly 14 dB with an input optical power of only 11 µW.
Additional Information© 2009 The American Physical Society. Received 24 May 2009; published 31 August 2009. The authors thank P. Herring and M. Eichenfield for early development of the double-disk structure. This work was supported by a DARPA seedling grant and the NSF (Grant No. 0622246).
Published - Lin2009p5906Phys_Rev_Lett.pdf
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