Nondestructive Testing of Thin Films by Harmonic Generation of Dispersive Rayleigh Waves

Abstract

A new and sensitive measurement technique of determining elastic properties of a thin film on a substrate based on harmonic generation of dispersive Rayleigh waves is demonstrated. The technique has a sensitivity of detecting a change of 0.001% in velocity due to the loading of the thin film. A damaged layer of about 20 Å on a mechanically polished LiNbO3 substrate is detectable.