TY - JOUR A1 - Wonneberger, R. A1 - Gräf, S. A1 - Bonse, Jörn A1 - Wisniewski, W. A1 - Freiberg, K. A1 - Hafermann, M. A1 - Ronning, C. A1 - Müller, F. A. A1 - Undisz, A. T1 - Tracing the Formation of Femtosecond Laser-Induced Periodic Surface Structures (LIPSS) by Implanted Markers N2 - The generation of laser-induced periodic surface structures (LIPSS) using femtosecond lasers facilitates the engineering of material surfaces with tailored functional properties. Numerous aspects of their complex formation process are still under debate, despite intensive theoretical and experimental research in recent decades. This particularly concerns the challenge of verifying approaches based on electromagnetic effects or hydrodynamic processes by experiment. In the present study, a marker experiment is designed to conclude on the formation of LIPSS. Well-defined concentration depth profiles of 55Mn+- and 14N+-ions were generated below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using ion implantation. Before and after LIPSS generation, marker concentration depth profiles and the sample microstructure were evaluated by using transmission electron microscopy techniques. It is shown that LIPSS predominantly formed by material removal through locally varying ablation. Local melting and resolidification with the redistribution of the material occurred to a lesser extent. The experimental design gives quantitative access to the modulation depth with a nanometer resolution and is a promising approach for broader studies of the interactions of laser beams and material surfaces. Tracing LIPSS formation enables to unambiguously identify governing aspects, consequently guiding the path to improved processing regarding reproducibility, periodicity, and alignment. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser processing KW - Ion implantation KW - Transmission Electron Microscopy (TEM) KW - Stainless steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623990 DO - https://doi.org/10.1021/acsami.4c14777 SN - 1944-8244 (Print) SN - 1944-8252 (Online) VL - 17 IS - 1 SP - 2462 EP - 2468 PB - ACS Publications AN - OPUS4-62399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hirahara, Kenta A1 - Bonse, Jörn A1 - Krüger, Jörg A1 - Weise, Matthias A1 - Ermilova, Elena A1 - Schusterbauer, Robert A1 - Unterreiner, Andreas-Neil A1 - Hertwig, Andreas T1 - A multi-method study of femtosecond laser modification and ablation of amorphous hydrogenated carbon coatings N2 - e present a study on femtosecond laser treatment of amorphous hydrogen-containing carbon coatings (a-C:H). The coatings were deposited on silicon wafers by a plasma-assisted chemical vapour deposition (PA-CVD), resulting in two different types of material with distinct properties (referred to as “absorbing” and “semi-transparent” coatings in the following). The samples were laser-treated with single fs-laser pulses (800 nm center wavelength, 35 fs pulse duration) in the ablative regime. Through a multi-method approach using topometry, Raman spectroscopy, and spectroscopic imaging ellipsometry, we can identify zones and thresholds of diferent fuence dependent efects and have access to the local dielectric function. The two coating materials react signifcantly diferent upon laser treatment. We determined the (non-ablative) modifcation threshold fuence for the absorbing coating as 3.6 × 10−2 Jcm−2 and its ablation threshold as 0.22 Jcm−2. The semi-transparent coating does not show such a low-fuence modifcation but exhibits a characteristic interference-based intra-flm ablation mechanism with two distinguishable ablation thresholds at 0.25 and 0.28 Jcm−2, respectively. The combination of tailored layer materials and correlative imaging spectroscopic methods delivers new insights into the behaviour of materials when treated with ultrashort-pulse laser radiation KW - Amorphous Hydrogenated Carbon Coatings KW - Correlative Imaging Measurement Techniques KW - Hybrid Metrology KW - Imaging Spectroscopy KW - Spectroscopic Ellipsometry KW - Ultra-short Pulse Laser Materials Processing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617829 DO - https://doi.org/10.1007/s00339-024-07980-z VL - 130 IS - 12 SP - 1 EP - 17 PB - Springer Science and Business Media LLC AN - OPUS4-61782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - de Eulate Pérez, Elisa García A1 - Wen, Keqing A1 - Voss, Heike A1 - Thiele, Dorothea A1 - Richter, Anja M. A1 - Bonse, Jörn T1 - Escherichia coli repellence via laser-induced periodic surface structures (LIPSS) on titanium: Critical role of biofilm-associated gene expression N2 - The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes. KW - Laser-induced periodic surface structures (LIPSS) KW - Titanium KW - Biofilm KW - Antifouling KW - Gene expression KW - Fluorescence microscopy PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655572 DO - https://doi.org/10.1016/j.apsusc.2026.166363 SN - 0169-4332 VL - 730 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-65557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -