Non-Destructive Analysis of Layered Materials by Depth Resolved Photoacoustic Imaging

Abstract

A new method of correlation photoacoustic imaging for the non-destructive depth-resolved analysis of a solid material has been developed. This method is made up of the two independently developed methods, thermal wave imaging and correlation photoacoustic spectroscopy. The new method has been applied to a layer-structured model sample where the separation of component layers is 15μm and found to be clearly resolved. As for color reversal films the depth resolution was about several μm for levels near the surface and somewhat less for the deeper levels.