Micro and nanopatterns can be produced on the surface of many materials using a wide range of manufacturing processes. Among them, laser-based approaches stand out for their high-throughput capability, high degree of flexibility, and resolutions even lower than the diffraction limit.[1] When it comes to industrial use, monitoring of laser-based methods is crucial for quality control of the structured patterns and for maintaining process stability and reproducibility. Particularly, methods based on scatterometry offer significant advantages for industrial monitoring because they are fast, non-contact, non-destructive, cost-effective, and they can resolve features down to the sub-microscale. In this study, an optical setup based on scatterometry is employed to monitor the topography of laser-microtextured stainless steel plates. The system is based on a low-power coherent light source that illuminates the sample surface. The scattered light is collected by a set of lenses and focused on a CCD camera where a distinctive pattern is recorded. The samples surfaces are produced by Direct Laser Interference Patterning (DLIP) and Laser-Induced Periodic Surface Structuring (LIPSS) using ps-pulsed laser sources. The designed optical configuration undergoes rigorous testing to ascertain its capabilities and limitations for indirect characterization of DLIP and LIPSS-treated surfaces.[2]. By analyzing the intensity and position of the diffraction orders in the CCD images, this methodology enables the estimation of spatial periods, structure depth, orientation, and regularity of the microtextures.

References

[1] A.Y. Vorobyev; C. Guo Laser & Photonics Reviews, 2012, 7, 385-407.

[2] N. Schröder; C. Fischer; M. Soldera; F. Bouchard; B. Voisiat; A.F. Lasagni Materials Letters, 2022, 324, 132794.