CICATA

Resumen: We report an approach to introduce the students to the field of the photothermal techniques. For this, we describe an experiment about the measurement of the periodical oscillations of the temperature in a body heated with a periodic heat source. These ...

We show that the front photoacoustic signal due to a sample consisting of a glass plate with a metal coated surface, at which thermal waves are generated by periodical light absorption, enhances for certain modulation frequencies when the other glass surface is covered with a liquid sample. This contradicts the intuitive expectation based on the assumption that the liquid provides a new channel for heat conduction thereby decreasing the substrate temperature. Experimental results are shown and the described effect is explained using a thermal wave interference model.