Precession Motion in Levitated Optomechanics

TL;DR

This paper experimentally studies the precession and nutation of a levitated non-spherical nanoparticle in vacuum, supported by a theoretical model and simulations that match experimental data, revealing precise torque measurements and sensitivities.

Contribution

It introduces the first detailed experimental observation and theoretical modeling of precession and nutation in levitated optomechanics, including torque measurement and sensitivity analysis.

Findings

Measured torque of approximately 1.9 x 10^{-23} Nm at 0.1 mbar.

Achieved torque sensitivity of about 3.6 x 10^{-31} Nm/√Hz at 10^{-7} mbar.

Developed a theoretical model that accurately predicts motional frequencies.

Abstract

We investigate experimentally the dynamics of a non-spherical levitated nanoparticle in vacuum. In addition to translation and rotation motion, we observe the light torque-induced precession and nutation of the trapped particle. We provide a theoretical model, which we numerically simulate and from which we derive approximate expressions for the motional frequencies. Both, the simulation and approximate expressions, we find in good agreement with experiments. We measure a torque of $1.9 \pm 0.5 \times 10^{-23}$ Nm at $1 \times 10^{-1}$ mbar, with an estimated torque sensitivity of $3.6 \pm 1.1 \times 10^{-31}$ Nm/$\sqrt{\text{Hz}}$ at $1 \times 10^{-7}$ mbar.