  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.
