Levitated optomechanics is showing potential for precise force measurements. Here, we report a case study, to show experimentally the capacity of such a force sensor. Using an electric field as a tool to detect a Coulomb force applied onto a levitated nanosphere. We experimentally observe the spatial displacement of up to 6.6 nm of the levitated nanosphere by imposing a DC field. We further apply an AC field and demonstrate resonant enhancement of force sensing when a driving frequency, ωAC, and the frequency of the levitated mechanical oscillator, ω0, converge. We directly measure a force of 3.0±1.5×10−20 N with 10 second integration time, at a centre of mass temperature of 3 K and at a pressure of 1.6×10−5 mbar.
@article{arxiv.1706.09774,
title = {Force sensing with an optically levitated charged nanoparticle},
author = {David Hempston and Jamie Vovrosh and Marko Toroš and George Winstone and Muddassar Rashid and Hendrik Ulbricht},
journal= {arXiv preprint arXiv:1706.09774},
year = {2018}
}