Mechanical Oscillation and Cooling Actuated by the Optical Gradient Force

Abstract

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 approximately 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 microW.

Observation of thermal feedback on the optical coupling noise of a microsphere attached to a low-spring-constant cantilever

“…When another dielectric device, such as another microresonator or waveguide, is brought into this intense field both devices feel a force due to the interaction of the dipoles in the material [3][4][5][6][7]. The sign of this force depends on the phase relationship between the electromagnetic fields connecting the two devices.…”

“…The field of optomechanics has expanded rapidly in the last decade due to the development of optical devices which are small enough to react to the minute forces created by photon radiation pressure [1,2] or intense optical gradients (i.e., dipole forces) [3][4][5][6][7]. Microscopic optical devices, such as whispering gallery resonators [8][9][10][11], tapered optical fibers [12], and photonic crystal cavities [13], enhance the strength of the electric field gradient due to high-optical-Q factors and small mode volumes [14,15].…”

Ultraefficient Cooling of Resonators: Beating Sideband Cooling with Quantum Control

“…The present state-of-the-art for cooling mechanical resonators is sideband cooling, which was originally developed in the context of cooling trapped ions [3][4][5]. This method is a powerful and practical technique, able to achieve large cooling factors, and these have been demonstrated in the laboratory [6][7][8][9][10][11][12][13][14][15].…”

“…The present state-of-the-art for cooling mechanical resonators is sideband cooling, which was originally developed in the context of cooling trapped ions [3][4][5]. This method is a powerful and practical technique, able to achieve large cooling factors, and these have been demonstrated in the laboratory [6][7][8][9][10][11][12][13][14][15].In the context of mechanical resonators, sideband cooling involves coupling the resonator to be cooled (from now on the "target") to a microwave or optical resonator (the "auxiliary") whose frequency is sufficiently high that it sits in its ground state at the ambient temperature. The resonators are coupled together by a linear interaction, and one that is straightforward to implement experimentally.…”

Spatial mapping of multimode Brownian motions in high-frequency silicon carbide microdisk resonators

“…To date, microdisk resonators have mainly been based on silicon (Si), silica (SiO 2 ) and silicon nitride (SiN) 22,23,26,27 .…”