Accurate modeling and characterization of photothermal forces in optomechanics

TL;DR

This paper develops a precise model for photothermal forces in optomechanics, validated through experiments on GaAs microdisks, highlighting the significance of surface effects and multiple thermal modes.

Contribution

It introduces a novel, accurate model for photothermal forces in optomechanical systems, improving upon previous approaches.

Findings

Excellent agreement between model predictions and experimental data

Surface photothermal forces significantly impact microphotonic device behavior

Multiple thermal modes must be considered for accurate modeling

Abstract

Photothermal effects have been pointed out as prominent sources of forces in optomechanical systems, competing with the standard radiation pressure interactions. In this Article, we derive a novel and accurate model for the prediction of photothermal forces and establish how some previous proposals can be complemented to yield precise results. As a proof-of-concept, we perform numerical and experimental tests on GaAs microdisks cavities and obtain striking agreement with our framework, revealing the importance of considering surface photothermal forces and the effects of multiple thermal modes in microphotonic devices.