Fig. 1: Dynamic thermal bistability in a silica microtoroid resonator26.
From: Optothermal dynamics in whispering-gallery microresonators

a Calculated transmission spectrum, cavity temperature, and resonance wavelength and the measured transmission spectrum during the wavelength up- and downscan processes. b Repeating transmission as a function of wavelength detuning in the upscanning (broadening) and downscanning (narrowing) processes. Reprinted with permission from ref. 26 [OSA The Optical Society]