Coherent oscillations of a levitated birefringent microsphere in vacuum driven by nonconservative rotation-translation coupling
Abstract
We demonstrate an effect whereby stochastic, thermal fluctuations combine with nonconservative optical forces to break detailed balance and produce increasingly coherent, apparently deterministic motion for a vacuum-trapped particle. The particle is birefringent and held in a linearly polarized Gaussian optical trap. It undergoes oscillations that grow rapidly in amplitude as the air pressure is reduced, seemingly in contradiction to the equipartition of energy. This behavior is reproduced in direct simulations and captured in a simplified analytical model, showing that the underlying mechanism involves nonsymmetric coupling between rotational and translational degrees of freedom. When parametrically driven, these self-sustained oscillators exhibit an ultranarrow linewidth of 2.2 μHz and an ultrahigh mechanical quality factor in excess of 2 × 108 at room temperature. Last, nonequilibrium motion is seen to be a generic feature of optical vacuum traps, arising for any system with symmetry lower than that of a perfect isotropic microsphere in a Gaussian trap.
Citation
Arita , Y , Simpson , S , Zemanek , P & Dholakia , K 2020 , ' Coherent oscillations of a levitated birefringent microsphere in vacuum driven by nonconservative rotation-translation coupling ' , Science Advances , vol. 6 , no. 23 , eaaz9858 . https://doi.org/10.1126/sciadv.aaz9858
Publication
Science Advances
Status
Peer reviewed
ISSN
2375-2548Type
Journal article
Description
Funding: UK Engineering and Physical Sciences Research Council (EP/P030017/1) and Czech Science Agency (GA19-17765S).Collections
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