Near-field ultrasonic Rayleigh waves from a laser line source

The generation of Rayleigh waves by a thermoelastic laser line source was studied to establish a quantitative basis for using this source in nondestructive testing and in materials characterization. Experiments using interferometric detection were carried out which showed that, for the near held of the line source, the Rayleigh pulse is a monopolar depression of uniform amplitude. A theoretical model was developed which led to an approximate expression in closed form for the normal surface displacement of the Rayleigh wave. Quantitative agreement was found for a parameter-free comparison between theory and experiment for the Rayleigh wave characteristics in both time and frequency domain.