Cavity Optomechanics in a Levitated Helium Drop

Abstract

We describe a proposal for a new type of optomechanical system based on a drop of liquid helium that is magnetically levitated in vacuum. In the proposed device, the drop would serve three roles: its optical whispering gallery modes would provide the optical cavity, its surface vibrations would constitute the mechanical element, and evaporation of He atoms from its surface would provide continuous refrigeration. We analyze the feasibility of such a system in light of previous experimental demonstrations of its essential components: magnetic levitation of mm-scale and cm-scale drops of liquid He, evaporative cooling of He droplets in vacuum, and coupling to high-quality optical whispering gallery modes in a wide range of liquids. We find that the combination of these features could result in a device that approaches the single-photon strong coupling regime, due to the high optical quality factors attainable at low temperatures. Moreover, the system offers a unique opportunity to use optical techniques to study the motion of a superfluid that is freely levitating in vacuum (in the case of ${}^4\mathrm{He}$). Alternatively, for a normal fluid drop of ${}^3\mathrm{He}$, we propose to exploit the coupling between the drop's rotations and vibrations to perform quantum non-demolition measurements of angular momentum.

13 pages, 6 figures

References in corpus (7)

• Cavity Opto-Mechanics with a Bose-Einstein Condensate
• Millikelvin cooling of an optically trapped microsphere in vacuum
• Large Quantum Superpositions and Interference of Massive Nanometer-Sized Objects
• Full Rotational Control of Levitated Silicon Nanorods
• Polygonal excitations of spinning and levitating droplets
• Spatio-Orientational Decoherence of Nanoparticles
• Photothermal optomechanics in superfluid helium coupled to a fiber-based cavity

Cited by in corpus (6)

• Harmonic and subharmonic waves on the surface of a vibrated liquid drop
• Dissipative phonon Fock state production in strong nonlinear optomechanics
• Superfluid Optomechanics with Phononic Nanostructures
• Demonstrating levitation within a microwave cavity
• Meissner levitation of a millimeter size neodymium magnet within a superconducting radio frequency cavity
• Decoherence of nonrelativistic bosonic quantum fields