Cancellation of photothermally induced instability in an optical resonator

TL;DR

This paper demonstrates a method to cancel optomechanical instability caused by photothermal effects in optical resonators by modifying the photothermal response to work with radiation pressure, enhancing stability in sensitive optical systems.

Contribution

It introduces a novel passive stabilization technique that reverses the sign of photothermal interaction to counteract instability in optomechanical cavities.

Findings

Photothermal effects can be controlled to stabilize optical resonators.

Reversing photothermal response leads to full system stability.

Applicable to high-sensitivity optical and optomechanical systems.

Abstract

Optical systems are often subject to parametric instability caused by the delayed response of the optical field to the system dynamics. In some cases, parasitic photothermal effects aggravate the instability by adding new interaction dynamics. This may lead to the possible insurgence or amplification of parametric gain that can further destabilize the system. In this paper, we show that the photothermal properties of an optomechanical cavity can be modified to mitigate or even completely cancel optomechanical instability. By inverting the sign of the photothermal interaction to let it cooperate with radiation pressure, we achieve control of the system dynamics to be fully balanced around a stable equilibrium point. Our study provides a feedback solution for optical control and precise metrological applications, specifically in high-sensitivity resonating systems that are particularly susceptible to parasitic photothermal effects, such as our test case of a macroscopic optical levitation setup. This passive stabilization technique is beneficial for improving system performance limited by photothermal dynamics in broad areas of optics, optomechanics, photonics, and laser technologies.