# Shot noise dominant regime for ellipsoidal nanoparticles in a linearly polarized beam

## TL;DR

This paper investigates the heating and cooling dynamics of anisotropic ellipsoidal nanoparticles in optical traps under shot noise dominance, highlighting how particle shape influences thermal behavior and cooling efficiency.

## Contribution

It provides new insights into how particle shape and size affect shot noise heating and cooling limits in optically trapped anisotropic nanoparticles.

## Key findings

- Smaller ellipticity reduces rotational heating.
- Larger particle size decreases relative heating rate.
- Feedback cooling can achieve lower occupation numbers depending on heating and measurement uncertainty.

## Abstract

Results on the heating and the parametric feedback cooling of an optically trapped anisotropic nanoparticle in the laser shot noise dominant regime are presented. The related dynamical parameters, such as the oscillating frequency and shot noise heating rate, depend on the shape of the trapped particle. For an ellipsoidal particle, the ratio of the axis lengths and the overall size controls the shot noise heating rate relative to the frequency. For a particle with smaller ellipticity or bigger size, the relative heating rate for rotation tends to be smaller than that for translation indicating a better rotational cooling. For one feedback scheme, we also present results on the lowest occupation number that can be achieved as a function of the heating rate and the amount of classical uncertainty in the position measurement.