Direct Laser Interference Patterning (DLIP) is considered as an emerging manufacturing technology to produce periodic surface structures with characteristic dimensions down to the micro- or submicron scale [1]. To integrate DLIP into industrial processes, it is essential to develop methods for monitoring the quality and homogeneity of the periodic microstructures, so that the process stability can be guaranteed with low reject rates and thus improved economic efficiency.

This study presents a comprehensive evaluation of the homogeneity of periodic line-like surface features fabricated on stainless steel (SS 1.4301) using DLIP. For laser texturing of microstructures with a spatial period (Λ) of 6 µm, a solid-state picosecond (pulse duration of τ = 12 ps) laser operating at 1064 nm is utilized in combination with a recently developed Extended Laser Interference Patterning System (ELIPSYS®, Surfunction GmbH). The research focuses on the challenges associated with producing homogeneous line-like surface patterns with a high Aspect Ratio (AR), examining the impact of process parameters such as pulse-to-pulse distance and laser repetition rate on the texture morphology and homogeneity. For quantitative evaluation of the structure homogeneity, a novel characterization method was developed, which is based on Gini analysis of two-dimensional Fast Fourier Transform (2D FFT) of topography images taken by confocal microscopy [2]. This method not only offers quantification of the texture homogeneity but also offers qualitative insights into the uniformity of the periodic patterns generated through DLIP.