Sensing of Static Forces with Free-Falling Nanoparticles

TL;DR

This paper introduces a new static-force sensing method using optically levitated nanoparticles, achieving high sensitivity and enabling studies of short-range forces and matter-wave interferometry with macroscopic objects.

Contribution

The authors develop a novel static-force sensing scheme with nanoparticles, overcoming limitations of resonant sensors and demonstrating unprecedented force sensitivity.

Findings

Force sensitivity of 10 aN achieved

Effective detection of gravitational and electric forces

Potential for advancing matter-wave interferometry

Abstract

Miniaturized mechanical resonators have proven to be excellent force sensors. However, they usually rely on resonant sensing schemes, and their excellent performance cannot be utilized for the detection of static forces. Here, we report on a novel static-force sensing scheme and demonstrate it using optically levitated nanoparticles in vacuum. Our technique relies on an off-resonant interaction of the particle with a weak static force, and a resonant read-out of the displacement caused by this interaction. We demonstrate a force sensitivity of $10\,\mathrm{aN}$ to static gravitational and electric forces acting on the particle. Our work not only provides a tool for the closer investigation of short-range forces, but also marks an important step towards the realization of matter-wave interferometry with macroscopic objects.