New calibration method for UV-VIS photothermal deflection spectroscopy set-up

Photothermal deflection spectroscopy has emerged as a useful technique for the determination of the absorption of materials with a small absorption coefficient. The technique offers relative values of the material absorptivity and, therefore, requires a calibration procedure in order to determine the absolute values. In this work, we present a new calibration method for a photothermal deflection spectroscopy set-up working in the UV-VIS, spectral range. The method is based on the use of reference samples with different levels of absorption. The samples, consisting of single thin films of amorphous carbon on transparent substrates, are optically characterized by means of spectrophotometric measurements. The accurate characterization of the samples enables the computation of their corresponding optical absorptivity in the PDS set-up. The calibration method is cross-checked by comparison of the measurements for the different reference samples and is finally applied to the study of the absorption of dielectric films in the UV.