HIGHLY SENSITIVE PHOTOTHERMAL DEFLECTION SPECTROSCOPY AT SOLID-LIQUID INTERFACES

Abstract

We have recently introduced a new photothermal technique based on the well-known $""mirage effect""^{1}$. Used at a solid-liquid interface, this method was found to be two orders of magnitude more sensitive than conventional photoacoustic $spectroscopy^{2}$. The application of this method both to metal-electrolyte and semiconductor-electrolyte interfaces will be illustrated. By replacing the intensity modulation by a polarization modulation of the light, we have just improved the performance of our instrument significantly. For example, we have been able to work on electrochemical deposition corresponding to one tenth of a monolayer of Cu on an unprepared Pt electrode.