Photothermal mirror Z-scan spectrometry of opaque samples

This contribution introduces a pump-probe photothermal mirror Z-scan method to measure the thermal quantum yield, the thermal diffusivity, and other photothermal parameters of an opaque solid. The focusing of a pump beam of light onto the sample generates thermoelastic surface distortions. The distorted surface acts as a mirror affecting the diffraction pattern of a reflected probe beam yielding the experimental signal. Scanning the focusing lens produces a single peak photothermal mirror Z-scan signature. The amplitude and time evolution of the signal determines the sample's photothermal properties. The method is used to analyze gallium arsenide and silicon plates, obtaining good agreement with previous studies. (C) 2019 Optical Society of America.