# Cavity cooling of an optically trapped nanoparticle

## TL;DR

This paper demonstrates cavity cooling of a dielectric nanoparticle trapped in an optical cavity, deriving the cooling force and showing effective cooling of both radial and axial motions through simulations.

## Contribution

It introduces a theoretical framework for cavity cooling of nanoparticles, including derivation of the frictional force and analysis of coupled motion.

## Key findings

- Cooling rate proportional to oscillation amplitude and frequency
- Nanoparticle cooled to 1/e of initial momentum in milliseconds
- Both radial and axial motions are effectively cooled

## Abstract

We study the cooling of a dielectric nanoscale particle trapped in an optical cavity. We derive the frictional force for motion in the cavity field, and show that the cooling rate is proportional to the square of oscillation amplitude and frequency. Both the radial and axial centre-of-mass motion of the trapped particle, which are coupled by the cavity field, are cooled. This motion is analogous to two coupled but damped pendulums. Our simulations show that the nanosphere can be cooled to 1/e of its initial momentum over time scales of hundredths of milliseconds.