Self-oscillations of an induced absorber (CdS) in a hybrid ring resonator

Abstract
We investigate the properties of a material with excitation-induced increase of absorption in a hybrid ring resonator. The material is CdS at room temperature, showing photothermal optical nonlinearities. After characterizing the nonlinear medium itself, we investigate the behavior in a short Fabry-Perot resonator and then present experimental as well as theoretical data for this induced absorber in the ring cavity. We show experimental indications for the appearance of the Farey-tree structure, which was predicted theoretically in a recent paper. The dependence of the oscillations on various parameters is discussed.