Theory of Scholte, leaky Rayleigh, and lateral wave excitation via the laser-induced thermoelastic effect

The analysis of the laser-induced thermoelastic excitation of acoustic waves propagating along a plane interface between two elastic media is presented. The general solution for the interface motion is derived. The detailed description of the liquid-solid interface motion caused by the photoexcited leaky Rayleigh, Scholte and lateral wave in the liquid is given both in frequency and time domain. The presented theory predicts that laser-induced thermoelastic stresses in the liquid and the solid can contribute in phase to the excitation of a Scholte wave and that the lateral wave excitation is suppressed when the light penetration depth and Scholte wave penetration depth in the liquid are equal. The obtained analytical solutions provide necessary theoretical background for the optimization of the laser-induced generation of interface waves in experiments. (C) 1996 Acoustical Society of America.