Controlling mode orientations and frequencies in levitated cavity optomechanics
Year: 2023
Authors: Pontin A., Fu H., Iacoponi J.H., Barker P.F., Monteiro T.S.
Autors Affiliation: UCL, Dept Phys & Astron, Gower St, London WC1E 6BT, England.
Abstract: Cavity optomechanics offers quantum ground state cooling, control and measurement of small mechanical oscillators. However optomechanical backactions disturb the oscillator motions: they shift mechanical frequen-cies and, for a levitated oscillator, rotate the spatial orientation of the mechanical modes. This introduces added imprecisions when sensing the orientation of an external force. For a nanoparticle trapped in a tweezer in a cavity populated only by coherently scattered (CS) photons, we investigate experimentally mode orientation, via the Sxy(co) mechanical cross-correlation spectra, as a function of the nanoparticle position in the cavity standing wave. We show that the CS field rotates the mechanical modes in the opposite direction to the cavity backaction, canceling the effect of the latter. It also opposes optical spring effects on the frequencies. We demonstrate a cancellation point, where it becomes possible to lock the modes near their unperturbed orientations and frequencies, independent of key experimental parameters, while retaining strong light-matter couplings that permit ground state cooling. This opens the way to sensing of directionality of very weak external forces, near quantum regimes.
Journal/Review: PHYSICAL REVIEW RESEARCH
Volume: 5 (1) Pages from: 13013-1 to: 13013-12
More Information: The authors would like to acknowledge helpful discussions with J. Gosling and M. Toros. The authors acknowledge funding from the Engineering and Physical Sciences Research Council (EPSRC) Grant No. EP/N031105/1. H.F. and J.H.I. acknowledge EPSRC studentship funding via Grants No. EP/L015242/1 (H.F.) and No. EP/R513143/1 (J.H.I.).KeyWords: Quantum Control; NanoparticleDOI: 10.1103/PhysRevResearch.5.013013