Evaluation of the possibility of using the laser-induced thermocapillary effect for photothermal spectroscopy

A new approach to the photothermal spectroscopy of solids and liquids is proposed on the basis of the thermocapillary effect, which arises when a laser beam excites a layer of liquid several hundreds of millimeters thick lying on a solid surface. The method uses the measurement of the diameter of a thermocapillary response or the counting of the number of fringes of equal thickness observed in the light reflected from a thermocapillary depression. The detectability threshold and the resolution of the method correspond to absorbed optical powers of, respectively, 500 and 100 mu W in the first case and 500 and 10 mu W in the second case. (c) 2005 Pleiades Publishing, Inc.