Coherent-scattering two-dimensional cooling in levitated cavity optomechanics

Toros, M. , Delic, U., Hales, F. and Monteiro, T. S. (2021) Coherent-scattering two-dimensional cooling in levitated cavity optomechanics. Physical Review Research, 3, 023071. (doi: 10.1103/PhysRevResearch.3.023071)

Abstract

The strong light-matter optomechanical coupling offered by coherent scattering set-ups have allowed the experimental realization of quantum ground-state cavity cooling of the axial motion of a levitated nanoparticle [U. Delić et al., Science 367, 892 (2020)]. An appealing milestone is now quantum two-dimensional (2D) cooling of the full in-plane motion, in any direction in the transverse plane. By a simple adjustment of the trap polarization, one obtains two nearly equivalent modes, with similar frequencies ω x ∼ ω y and optomechanical couplings g x ≃ g y —in this experimental configuration we identify an optimal trap ellipticity, nanosphere size, and cavity linewidth which allows for efficient 2D cooling. Moreover, we find that 2D cooling to occupancies n x + n y ≲ 1 at moderate vacuum ( 10 − 6 mbar) is possible in a “Goldilocks” zone bounded by √ κ Γ / 4 ≲ g x , g y ≲ ∣ ∣ ω x − ω y ∣ ∣ ≲ κ , where one balances the need to suppress dark modes while avoiding far-detuning of either mode or low cooperativities, and κ ( Γ ) is the cavity decay rate (motional heating rate). With strong-coupling regimes g x , g y ≳ κ in view one must consider the genuine three-way hybridization between x , y and the cavity light mode resulting in hybridized bright/dark modes. Finally, we show that bright/dark modes in the levitated set-up have a simple geometrical interpretation, related by rotations in the transverse plane, with implications for directional sensing.

• Item Type: Articles
• Additional Information: This work was supported by the Engineering and Physical Sciences Research Council [EP/N031105/1 and EP/L015242/1]. M.T. acknowledges funding by the Leverhulme Trust (RPG-2020-197). U.D. acknowledges support from the European Research Council (ERC CoG QLev4G) and the research platform TURIS at the University of Vienna
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Toros, Dr Marko
• Authors: Toros, M., Delic, U., Hales, F., and Monteiro, T. S.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review Research
• Publisher: American Physical Society
• ISSN: 2643-1564
• ISSN (Online): 2643-1564
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Physical Review Research 3:023071
• Publisher Policy: Reproduced under a Creative Commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
308508		Quantum Mechanics in a Rotating World	Miles Padgett	Leverhulme Trust (LEVERHUL)	RPG-2020-197	P&S - Physics & Astronomy