Topography Analysis and Homogeneity Quantification of Laser-Patterned Periodic Surface Structures

Abstract

Functionalization of surfaces by engraving micro or nano-textures using laser-based methods has become a broad field of research with potential for large-scale manufacturing. Particularly, Di-rect Laser Interference Patterning (DLIP) is a surface structuring method that allows the fabrication of periodic structures with resolutions down to the micro or submicron scale with throughputs even over 1 m2/min. However, the production of large areas with high texture quality and reproducibility is still challenging. One of the reasons for this, is the lack of an objective methodology to quantify the texture homogeneity so that different processing conditions can be compared to find the opti-mum laser process window. In this study, a statistical analysis based on the Gini coefficient is em-ployed to quantitatively assess the homogeneity of DLIP-produced textures on three coating sys-tems. The method allowed for an objective comparison of the impact of the process conditions on the different materials. For instance, it was observed that within the set of studied parameters the number of applied pulses has a higher impact on the texture homogeneity than the fluence per pulse and that the optimum number of pulses for the studied process lies between 10 and 20