The concise treatise on thermal and optical characterization of a wide variety of samples by means of laser photoacoustic and thermooptical spectroscopies

Abstract

In recent years the class of photothermal (PT) spectroscopy emerged as a valuable tool for optical and thermal characterization of a wide range of samples offering potentially significant improvements (high sensitivity and precision) above traditional methods. Essentially, it implies an interaction of the modulated radiation with the absorbing sample that, in the absence of photochemistry or fluorescence, leads to nonradiative processes and hence to the temperature rise within the sample. The energy absorbed by the sample is thus converted into the heat and this effect can be detected within, on or above the absorbing sample using either pressure or optical sensors. Based on the above, large variety of experimental schemes ranging from very simple to sophisticated ones have been proposed and used.