Optimal Position Detection of an Optically Levitated Mie Particle

TL;DR

This paper proposes an optimal detection scheme for the position of optically levitated Mie particles, introducing the concept of an information radiation field (IRF) to maximize information retrieval and facilitate ground-state cooling.

Contribution

It introduces the IRF concept and an optimal detection scheme for arbitrary particles, enhancing precision in levitated optomechanics experiments.

Findings

Backward detection with a Gaussian beam captures sufficient information for ground-state cooling.

Analysis of information loss in objective collection and mode-matching.

Optimal detection scheme improves position measurement accuracy.

Abstract

We theoretically investigate the problem of position detection of an optically levitated Mie particle. The information radiation field (IRF) is proposed and defined to characterize the scattered light carrying complete information about the center-of-mass (c.m.) motion of the particle. Based on the IRF, we suggest an optimal detection scheme for the position of arbitrary particles. We calculate both the information losses of objective collection and mode-matching in levitated optomechanical experiments. Our results conclude that the backward detection scheme, using an incident Gaussian beam focused by a high numerical aperture lens, provides sufficient information to achieve the quantum ground state through cooling of the three-dimensional c.m. motion of the Mie particle.