Quantum limit of photothermal cooling

TL;DR

This paper investigates the fundamental limits of cooling a mechanical oscillator via photothermal forces, incorporating photon absorption noise to accurately estimate the lowest achievable phonon occupation.

Contribution

It introduces a noise-inclusive model for photothermal cooling, providing new insights into the minimal phonon number achievable in realistic conditions.

Findings

Photon absorption noise significantly affects cooling limits

Estimated lowest phonon occupation in realistic scenarios

Model extends understanding of photothermal cooling efficiency

Abstract

We study the problem of cooling a mechanical oscillator using the photothermal (bolometric) force. Contrary to previous attempts to model this system, we take into account the noise effects due to the granular nature of photon absorption. This allows us to tackle the cooling problem down to the noise dominated regime and to find reasonable estimates for the lowest achievable phonon occupation in the cantilever.