Non-contact Characterization of the Modified Surface Layer by the Inverse Analysis of Laser Surface Acoustic Waves

Abstract

Non-contact characterization of the modified surface layer was attempted by the quantitative analysis of the laser surface acoustic wave (SAW). Velocity and attenuation dispersion of the Rayleigh and Lamb waves were obtained by the novel laser SAW system, and used to estimate the thickness, elastic properties, density (purity) and further the bond quality and structure of the surface film. This paper introduces two laser SAW systems developed, sophisticated signal processing to obtain the velocity dispersion, and application to characterize the electro-plated silver layer, diffusion bonded metallic laminate, vapor deposited ceramic layer and porous silicon.