Analysis of surface processes by means of speckle-correlation

Changes in the micro-profile of rough surfaces are analysed by correlation of digital images of speckle patterns resulting from laser light scattered at the surfaces. The quantitative interpretation of decorrelations is based on a theoretical model and its verification by alternative measurements on sample objects. Profile changes of some 10 nm are well resolved. The scope of applications is illustrated on the corrosion process of an iron probe a nd the removal of a patina layer from a stone by laser ablation.