Credit: Light: Science & Applications
A schematic illustration of the photothermal microscopy setup. The pump light travels through free space, guided by a galvo mirror (GM) that controls the position of the laser spot on the microtoroid. The probe light is coupled to the microtoroid through a tapered fiber to track the resonance wavelength of the microcavity. The GM scanning system enables a 2D spatial scan of the pump laser on the microtoroid plane.