Classical and quantum theory of photothermal cavity cooling of a mechanical oscillator

The optomechanical coupling between a mechanical oscillator and light trapped in a cavity has been the subject of many recent investigations. One salient feature of this coupling is the possibility to cavity-cool a mechanical oscillator down to its quantum ground state. The standard situation studied in most optomechanics experiments pictures the scenario of a Fabry-Perot cavity´s end mirror light enough to undergo the mechanical force induced by photons bouncing back on the mirror. Here we are interested in scenarios where the photons are, at least partially, absorbed. As a result of the end mirror absorption, a photothermal force can be produced which can overcome radiation pressure by several orders of magnitude in experimental settings. This force was already shown to enable very efficient cavity-cooling or dynamical pumping of mechanical oscillators. In this work, we present a classical and a quantum theory of photothermal cavity cooling of a mechanical oscillator.