Process study for laser-induced surface coloration

A KrF excimer laser beam is used to induce controllable and high-contrast colors on a stainless-steel surface under different processing conditions. The laser beam acts as a localized heating source that promotes the formation of semitransparent oxide films of varying thicknesses and morphologies on the sample surface. Ellipsometry and atomic force microscopy were employed to understand the laser-induced colors by studying the surface morphology and optical properties of the oxide films and their thickness. It is found that the laser-induced colors vary with the oxide layer thickness. The laser-treated areas have granular structures, which affect oxide growth and light scattering.