TY - JOUR A1 - Lone, S. A. A1 - Muck, M. A1 - Fosodeder, P. A1 - Mardare, C.C. A1 - Florian, Camilo A1 - Weth, A. A1 - Krüger, Jörg A1 - Steinwender, C. A1 - Baumgartner, W. A1 - Bonse, Jörn A1 - Heitz, J. A1 - Hassel, A.W. T1 - Impact of Femtosecond Laser Treatment Accompanied with Anodization of Titanium Alloy on Fibroblast Cell Growth N2 - Herein, Ti6Al4V alloy is surface modified by femtosecond laser ablation. The microstructure image obtained by secondary electron microscopy reveals a combination of micrometer spikes or cones superimposed by nanoripples (laser‐induced periodic surface structures). To make the surface hydrophilic, anodization is performed resulting in further smoothness of microstructure and a final thickness of 35 ± 4 nm is estimated for oxide produced after anodization at 10 V (scan rate = 0.1 V s−1) versus standard hydrogen electrode. The obtained electrochemically active surface area (ECSA) is approximately 8 times larger compared with flat mirror polished Ti6Al4V surface. Combined chemical analysis by Pourbaix diagram and X‐ray photoelectron spectroscopy (XPS) analyses reveal that titanium and aluminum are passivating into TiO2 and Al2O3, but the dissolution of aluminum in the form of solvated ion is inevitable. Finally, cell seeding experiments on anodized and laser‐treated titanium alloy samples show that the growth of murine fibroblast cells is significantly suppressed due to unique surface texture of the laser‐treated and anodized titanium alloy sample. KW - Anodization KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures, LIPSS KW - Ti6Al4V alloys KW - X-ray photoelectron spectroscopy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510263 DO - https://doi.org/https://doi.org/10.1002/pssa.201900838 SN - 1862-6300 SN - 1862-6319 VL - 217 IS - 13 SP - 1900838-1 EP - 1900838-9 PB - WILEY-VCH Verlag CY - Weinheim, Germany AN - OPUS4-51026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Surface functionalization by laser-induced periodic surface structures N2 - In recent years, the improved understanding of the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical, and chemical properties of many materials. Such structures strongly depend on the laser beam polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. The most accepted explanation for the origin of the structures is based on the interference of the incident laser radiation with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periods ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelengths, pulse durations and repetition rate laser sources, customized micro- and nanometric spatial resolutions, and compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces, and bacterial and cell growth for medical devices, among many others. KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Surface functionalization KW - Applications PY - 2020 DO - https://doi.org/10.2351/7.0000103 SN - 1938-1387 VL - 32 IS - 2 SP - 022063 PB - Laser Institute of America AN - OPUS4-50780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezera, Marek A1 - Alamri, S. A1 - Hendriks, W. A. P. M. A1 - Hertwig, Andreas A1 - Elert, Anna Maria A1 - Bonse, Jörn A1 - Kunze, T. A1 - Lasagni, A. F. A1 - Römer, G. R. B. E. T1 - Hierarchical micro-/nano-structures on polycarbonate via UV pulsed laser processing N2 - Hierarchical micro/-nanostructures were produced on polycarbonate polymer surfaces by employing a two-step UV-laser processing strategy based on the combination of Direct Laser Interference Patterning (DLIP) of gratings and pillars on the microscale (3 ns, 266 nm, 2 kHz) and subsequently superimposing Laser-induced Periodic Surface Structures (LIPSS; 7–10 ps, 350 nm, 100 kHz) which adds nanoscale surface features. Particular emphasis was laid on the influence of the direction of the laser beam polarization on the morphology of resulting hierarchical surfaces. Scanning electron and atomic force microscopy methods were used for the characterization of the hybrid surface structures. Finite-difference time-domain (FDTD) calculations of the laser intensity distribution on the DLIP structures allowed to address the specific polarization dependence of the LIPSS formation observed in the second processing step. Complementary chemical analyzes by micro-Raman spectroscopy and attenuated total reflection Fourier-transform infrared spectroscopy provided in-depth information on the chemical and structural material modifications and material degradation imposed by the laser processing. It was found that when the linear laser polarization was set perpendicular to the DLIP ridges, LIPSS could be formed on top of various DLIP structures. FDTD calculations showed enhanced optical intensity at the topographic maxima, which can explain the dependency of the morphology of LIPSS on the polarization with respect to the orientation of the DLIP structures. It was also found that the degradation of the polymer was enhanced for increasing accumulated fluence levels. KW - Direct laser interference patterning KW - Laser-induced periodic surface structures (LIPSS) KW - Polycarbonate KW - Hierarchical structures KW - Surface functionalization PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509101 DO - https://doi.org/10.3390/nano10061184 SN - 2079-4991 VL - 10(6) IS - Special issue "Laser-generated periodic nanostructures" SP - 1184-1 EP - 1184-19 PB - MDPI CY - Basel AN - OPUS4-50910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Gräf, S. T1 - Maxwell Meets Marangoni — A Review of Theories on Laser‐Induced Periodic Surface Structures N2 - Surface nanostructuring enables the manipulation of many essential surface properties. With the recent rapid advancements in laser technology, a contactless large‐area processing at rates of up to m2 s−1 becomes feasible that allows new industrial applications in medicine, optics, tribology, biology, etc. On the other hand, the last two decades enable extremely successful and intense research in the field of so‐called laser‐induced periodic surface structures (LIPSS, ripples). Different types of these structures featuring periods of hundreds of nanometers only—far beyond the optical diffraction limit—up to several micrometers are easily manufactured in a single‐step process and can be widely controlled by a proper choice of the laser processing conditions. From a theoretical point of view, however, a vivid and very controversial debate emerges, whether LIPSS originate from electromagnetic effects or are caused by matter reorganization. This article aims to close a gap in the available literature on LIPSS by reviewing the currently existent theories of LIPSS along with their numerical implementations and by providing a comparison and critical assessment of these approaches. KW - Laser-induced periodic surface structures (LIPSS) KW - Electromagnetic theories KW - Matter reorganization theories KW - Surface plasmon polaritons KW - Self-organization PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514089 DO - https://doi.org/10.1002/lpor.202000215 SN - 1863-8899 VL - 14 IS - 10 SP - 2000215-1 EP - 2000215-25 PB - Wiley CY - Berlin AN - OPUS4-51408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ringleb, F. A1 - Eylers, K. A1 - Teubner, T. A1 - Boeck, T. A1 - Symietz, Christian A1 - Bonse, Jörn A1 - Andree, Stefan A1 - Krüger, Jörg A1 - Heidmann, B. A1 - Schmid, M. A1 - Lux-Steiner, M. T1 - Regularly arranged indium islands on glass/molybdenum substrates upon femtosecond laser and physical vapor deposition processing N2 - A bottom-up approach is presented for the production of arrays of indium islands on a molybdenum layer on glass, which can serve as micro-sized precursors for indium compounds such as copper-indium-gallium-diselenide used in photovoltaics. Femtosecond laser ablation of glass and a subsequent deposition of a molybdenum film or direct laser processing of the molybdenum film both allow the preferential nucleation and growth of indium islands at the predefined locations in a following indium-based physical vapor deposition (PVD) process. A proper choice of laser and deposition parameters ensures the controlled growth of indium islands exclusively at the laser ablated spots. Based on a statistical analysis, these results are compared to the non-structured molybdenum surface, leading to randomly grown indium islands after PVD. KW - Femtosecond laser KW - Physical vapor deposition KW - Indium KW - Molybdenum substrate KW - Microconcentrator solar cell PY - 2016 DO - https://doi.org/10.1063/1.4943794 SN - 0003-6951 VL - 108 IS - 11 SP - 111904-1 EP - 111904-4 AN - OPUS4-35602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grehn, M. A1 - Seuthe, T. A1 - Höfner, M. A1 - Griga, N. A1 - Theiss, C. A1 - Mermillod-Blondin, A. A1 - Eberstein, Markus A1 - Eichler, H. A1 - Bonse, Jörn T1 - Femtosecond-laser induced ablation of silicate glasses and the intrinsic dissociation energy N2 - The relation between ablation threshold fluence upon femtosecond laser pulse irradiation and the average dissociation energy density of silicate based multicomponent glass is studied. A simple model based on multiphoton absorption quantifies the absorbed energy density at the ablation threshold fluence. This energy density is compared to a calculated energy density which is necessary to decompose the glass compound into its atomic constituents. The results confirm that this energy density is a crucial intrinsic material parameter for the description of the femtosecond laser ablation threshold fluence of dielectrics. PY - 2014 DO - https://doi.org/10.1364/OME.4.000689 SN - 2159-3930 VL - 4 IS - 4 SP - 689 EP - 700 PB - OSA CY - Washington, DC AN - OPUS4-30475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Höhm, S. A1 - Koter, Robert A1 - Hartelt, Manfred A1 - Spaltmann, Dirk A1 - Pentzien, Simone A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Tribological performance of sub-100-nm femtosecond laser-induced periodic surface structures on titanium N2 - Sub-100-nm laser-induced periodic surface structures (LIPSS) were processed on bulk titanium (Ti) surfaces by femtosecond laser pulse irradiation in air (30 fs pulse duration, 790 nm wavelength). The laser peak fluence, the spatial spot overlap, and the number of overscans were optimized in a sample-scanning geometry in order to obtain large surface areas (5 mm × 5 mm) covered homogeneously by the LIPSS. The laser-processed regions were characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). The friction coefficient of the nanostructured surfaces was tested during 1000 cycles under reciprocal sliding conditions (1 Hz, 1.0 N normal load) against a 10-mm diameter ball of hardened 100Cr6 steel, both in paraffin oil and in engine oil used as lubricants. Subsequently, the corresponding wear tracks were qualified by OM, SEM, and energy dispersive X-ray analyses (EDX). The results of the tribological tests are discussed and compared to that obtained for near wavelength-sized fs-LIPSS, processed under somewhat different irradiation conditions. Some constraints for a beneficial effect of LIPSS on the tribological performance are provided. KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures, LIPSS KW - Friction KW - Wear KW - Nanostructures KW - Surface functionalization PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S0169433215026987 DO - https://doi.org/10.1016/j.apsusc.2015.11.019 SN - 0169-4332 SN - 1873-5584 VL - 374 SP - 190 EP - 196 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-35937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhm, S. A1 - Herzlieb, M. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Dynamics of the formation of laser-induced periodic surface structures (LIPSS) upon femtosecond two-color double-pulse irradiation of metals, semiconductors, and dielectrics N2 - In order to address the dynamics and physical mechanisms of LIPSS formation for three different classes of materials (metals, semiconductors, and dielectrics), two-color double-fs-pulse experiments were performed on Titanium, Silicon and Fused Silica. For that purpose a Mach–Zehnder interferometer generated polarization controlled (parallel or cross-polarized) double-pulse sequences at 400 nm and 800 nm wavelength, with inter-pulse delays up to a few picoseconds. Multiple of these two-color double-pulse sequences were collinearly focused by a spherical mirror to the sample surfaces. The fluence of each individual pulse (400 nm and 800 nm) was always kept below its respective ablation threshold and only the joint action of both pulses lead to the formation of LIPSS. Their resulting characteristics (periods, areas) were analyzed by scanning electron microscopy. The periods along with the LIPSS orientation allow a clear identification of the pulse which dominates the energy coupling to the material. For strong absorbing materials (Silicon, Titanium), a wavelength-dependent plasmonic mechanism can explain the delay-dependence of the LIPSS. In contrast, for dielectrics (Fused Silica) the first pulse always dominates the energy deposition and LIPSS orientation, supporting a non-plasmonic formation scenario. For all materials, these two-color experiments confirm the importance of the ultrafast energy deposition stage for LIPSS formation. KW - Femtosecond laser ablation KW - Double-pulse experiments KW - Laser-induced periodic surface structures (LIPSS) KW - Mach-Zehnder interferometer KW - Ultrafast optical techniques PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S0169433215031347 DO - https://doi.org/10.1016/j.apsusc.2015.12.129 SN - 0169-4332 SN - 1873-5584 VL - 374 SP - 331 EP - 338 PB - Elsevier CY - Amsterdam, Netherlands AN - OPUS4-35938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Zergioti, I. A1 - Delaporte, P. A1 - Scarisoreanu, N. D. T1 - Preface - E-MRS 2015 Spring Meeting Symposium CC: “Laser and plasma processing for advanced applications in material science”, 11-15 May 2015, Lille (France) N2 - This article represents the editorial preface for the proceedings of the Symposium CC “Laser and plasma processing for advanced applications in material science” held from May 11th to 15th 2015 in the Lille Grand Palais, France, during the annual Spring Meeting of the European Materials Research Society (E-MRS). KW - Laser processing KW - Plasma processing KW - Material sciences KW - Advanced applications PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S0169433216307243 DO - https://doi.org/10.1016/j.apsusc.2016.03.231 SN - 0169-4332 SN - 1873-5584 VL - 374 SP - 1 EP - 1 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-35939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Florian, Camilo A1 - Wonneberger, R. A1 - Undisz, A. A1 - Kirner, Sabrina V. A1 - Wasmuth, Karsten A1 - Spaltmann, Dirk A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Chemical effects during the formation of various types of femtosecond laser-generated surface structures on titanium alloy N2 - In this contribution, chemical, structural, and mechanical alterations in various types of femtosecond laser-generated surface structures, i.e., laser-induced periodic surface structures (LIPSS, ripples), Grooves, and Spikes on titanium alloy, are characterized by various surface analytical techniques, including X-ray diffraction and glow-discharge optical emission spectroscopy. The formation of oxide layers of the different laser-based structures inherently influences the friction and wear performance as demonstrated in oil-lubricated reciprocating sliding tribological tests (RSTTs) along with subsequent elemental mapping by energy-dispersive X-ray analysis. It is revealed that the fs-laser scan processing (790 nm, 30 fs, 1 kHz) of near-wavelength-sized LIPSS leads to the formation of a graded oxide layer extending a few hundreds of nanometers into depth, consisting mainly of amorphous oxides. Other superficial fs-laser-generated structures such as periodic Grooves and irregular Spikes produced at higher fluences and effective number of pulses per unit area present even thicker graded oxide layers that are also suitable for friction reduction and wear resistance. Ultimately, these femtosecond laser-induced nanostructured surface layers efficiently prevent a direct metal-to-metal contact in the RSTT and may act as an anchor layer for specific wear-reducing additives contained in the used engine oil. KW - Laser-induced oxide layer KW - Laser-induced periodic surface strctures (LIPSS) KW - Femtosecond laser processing KW - Tribology KW - Surface processing PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505660 DO - https://doi.org/10.1007/s00339-020-3434-7 SN - 0947-8396 SN - 1432-0630 VL - 126 IS - 4 SP - 266 PB - Springer Nature Switzerland AG AN - OPUS4-50566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray radiation protection aspects during ultrashort laser processing N2 - Ultrashort pulse laser processing of materials allows for precise machining with high accuracy. By increasing the repetition rate to several 100 kHz, laser machining becomes quick and cost-effective. Ultrafast laser processing at high repetition rates and peak intensities above 10^13 W/cm^2 can cause a potential hazard by generation of unwanted x-ray radiation. Therefore, radiation protection must be considered. For 925 fs pulse duration at a center wavelength of 1030 nm, the x-ray emission in air at a repetition rate of 400 kHz was investigated up to a peak intensity of 2.6 × 10^14 W/cm^2. Based on the presented measurements, the properties of potential shielding materials will be discussed. By extending our previous works, a scaling of the x-ray radiation emission to higher peak intensities up to 10^15 W/cm^2 is described, and emitted x-ray doses are predicted. KW - Laser ablation KW - Ultrashort pulse laser processing KW - Laser-induced x-ray emission KW - Radiation protection PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505677 DO - https://doi.org/10.2351/1.5134778 VL - 32 IS - 2 SP - 022004 AN - OPUS4-50567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Menzel, F. A1 - Epperlein, N. A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Bacterial adhesion on femtosecond laser-modified polyethylene N2 - In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced. KW - Bacterial adhesion KW - Laser-modified surface KW - Polyethylene KW - Laser-induced nanostructures KW - Biofilm PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492280 DO - https://doi.org/10.3390/ma12193107 VL - 12 IS - 19 SP - 3107 PB - MDPI CY - Basel, Schweiz AN - OPUS4-49228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kunz, C. A1 - Bonse, Jörn A1 - Spaltmann, Dirk A1 - Neumann, C. A1 - Turchanin, A. A1 - Bartolomé, J. F. A1 - Müller, F. A. A1 - Gräf, S. T1 - Tribological performance of metal-reinforced ceramic composites selectively structured with femtosecond laser-induced periodic surface structures N2 - The impact of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on tribological properties was investigated for metal-reinforced ceramic composites (Al2O3-ZrO2-Nb). For this purpose, the metallic niobium (Nb) phase was selectively structured with LIPSS in an air environment with different values of the fs-laser peak fluence by near-infrared fs-laser radiation (λ = 1025 nm, τ = 300 fs, frep = 1 kHz), taking advantage of the different light absorption behavior of ceramic and metal. The tribological performance was evaluated by reciprocating sliding tests in a ball-on-disc configuration using Ringer's solution as lubricant. The surfaces were characterized before and after laser irradiation by optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and by measuring the contact angle with Ringer's solution. The LIPSS formation resulted in an increased wetting of the surface with the lubricant. Moreover, the selectively structured composite surfaces revealed a coefficient of friction significantly reduced by a factor of ~3 when compared to the non-irradiated surface. Furthermore, the formation of a laser-induced oxidation layer was detected with NbO as the most prominent oxidation state. Selectively structured composites with outstanding mechanical properties and enhanced tribological performance are of particular interest for biomedical applications. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Ceramic matrix composites KW - Tribology PY - 2020 DO - https://doi.org/10.1016/j.apsusc.2019.143917 SN - 0169-4332 SN - 1873-5584 VL - 499 IS - 1 SP - 143917 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-49255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - The influence of processing parameters on X‑ray emission during ultra‑short pulse laser machining N2 - During ultra-short laser material processing at high laser pulse repetition rates unwanted X-ray radiation can be generated in a quantity that may constitute a potential risk for health. An adequate X-ray radiation protection requires a thoroughly understanding of the influence of the laser processing parameters on the generation of X-ray radiation. In the present work, the generated X-ray dose during laser machining was investigated in air for varying beam scanning conditions at a pulse duration of 925 fs, a center wavelength of 1030 nm and a laser peak intensity of 2.6 × 10^14 W/cm^2. The X-ray radiation dose and the corresponding spectral X-ray emission were investigated in dependence on the laser’s pulse repetition rate and on the beam scanning speed. The results show a strong dependence of the X-ray emission on these laser processing parameters. KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Femtosecond laser KW - Radiation protection PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486441 DO - https://doi.org/10.1007/s00339-019-2827-y SN - 0947-8396 SN - 1432-0630 VL - 125 IS - 8 SP - 570, 1 EP - 8 PB - Springer AN - OPUS4-48644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cubero, A. A1 - Martínez, E. A1 - Angurel, L.A. A1 - de la Fuente, G.F. A1 - Navarro, R. A1 - Legall, Herbert A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Surface superconductivity changes of niobium sheets by femtosecond laser-induced periodic nanostructures N2 - Irradiation with ultra-short (femtosecond) laser beams enables the generation of sub-wavelength laser-induced periodic surface structures (LIPSS) over large areas with controlled spatial periodicity, orientation, and depths affecting only a material layer on the sub-micrometer scale. This study reports on how fs-laser irradiation of commercially available Nb foil samples affects their superconducting behavior. DC magnetization and AC susceptibility measurements at cryogenic temperatures and with magnetic fields of different amplitude and orientation are thus analyzed and reported. This study pays special attention to the surface superconducting layer that persists above the upper critical magnetic field strength Hc2, and disappears at a higher nucleation field strength Hc3. Characteristic changes were distinguished between the surface properties of the laser-irradiated samples, as compared to the corresponding reference samples (non-irradiated). Clear correlations have been observed between the surface nanostructures and the nucleation field Hc3, which depends on the relative orientation of the magnetic field and the surface patterns developed by the laser irradiation. KW - Niobium KW - Surface superconductivity KW - Laser-induced periodic surface structures (LIPSS) KW - Nanostructures PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518462 DO - https://doi.org/10.3390/nano10122525 SN - 2079-4991 VL - 10(12) IS - Special issue "Laser-generated periodic nanostructures" SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-51846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ayerdi, J. J. A1 - Aginagalde, A. A1 - Llavori, I. A1 - Bonse, Jörn A1 - Spaltmann, Dirk A1 - Zabala, A. T1 - Ball-on-flat linear reciprocating tests: Critical assessment of wear volume determination methods and suggested improvements for ASTM N2 - In the present work it was shown the importance of the correct selection, implementation, and reporting of wear volume computation method and quanitifies the potential errors. KW - Wear KW - Sliding KW - Surface KW - Analysis KW - ASTM KW - D7755-11 PY - 2021 DO - https://doi.org/10.1016/j.wear.2021.203620 VL - 470-471 SP - 3620 AN - OPUS4-52080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezera, M. A1 - Bonse, Jörn A1 - Römer, G.R.B.E. T1 - Influence of Bulk Temperature on Laser-Induced Periodic Surface Structures on Polycarbonate N2 - In this paper, the influence of the bulk temperature (BT) of Polycarbonate (PC) on the occurrence and growth of Laser-induced Periodic Surface Structures (LIPSS) is studied. Ultrashort UV laser pulses with various laser peak fluence levels F_0 and various numbers of overscans (N_OS) were applied on the surface of pre-heated Polycarbonate at different bulk temperatures. Increased BT leads to a stronger absorption of laser energy by the Polycarbonate. For N_OS < 1000 High Spatial Frequency LIPSS (HSFL), Low Spatial Frequency LIPSS perpendicular (LSFL-I) and parallel (LSFL-II) to the laser polarization were only observed on the rim of the ablated tracks on the surface but not in the center of the tracks. For N_OS ≥ 1000 , it was found that when pre-heating the polymer to a BT close its glass transition temperature (T_g), the laser fluence to achieve similar LIPSS as when processed at room temperature decreases by a factor of two. LSFL types I and II were obtained on PC at a BT close to T_g and their periods and amplitudes were similar to typical values found in the literature. To the best of the author’s knowledge, it is the first time both LSFL types developed simultaneously and consistently on the same sample under equal laser processing parameters. The evolution of LIPSS from HSFL, over LSFL-II to LSFL I, is described, depending on laser peak fluence levels, number of pulses processing the spot and bulk temperature. KW - Laser-induced periodic surface structures (LIPSS) KW - Polycarbonate KW - Bulk temperature KW - Ultrashort laser pulses PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498242 UR - https://www.mdpi.com/2073-4360/11/12/1947 DO - https://doi.org/https://doi.org/10.3390/polym11121947 SN - 2073-4360 VL - 11 IS - 12 SP - 1947 PB - MDPI CY - Basel, Switzerland AN - OPUS4-49824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Florian, Camilo A1 - Déziel, J.-L. A1 - Kirner, Sabrina V. A1 - Siegel, J. A1 - Bonse, Jörn T1 - The role of the laser-induced oxide layer in the formation of laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS) are often present when processing solid targets with linearly polarized ultrashort laser pulses. The different irradiation parameters to produce them on metals, semiconductors and dielectrics have been studied extensively, identifying suitable regimes to tailor its properties for applications in the fields of optics, medicine, fluidics and tribology, to name a few. One important parameter widely present when exposing the samples to the high intensities provided by these laser pulses in air environment, that generally is not considered, is the formation of a superficial laser-induced oxide layer. In this paper, we fabricate LIPSS on a layer of the oxidation prone hard-coating material chromium nitride in order to investigate the impact of the laser-induced oxide layer on its formation. A variety of complementary surface analytic techniques were employed, revealing morphological, chemical and structural characteristics of well-known high-spatial frequency LIPSS (HSFL) together with a new type of low-spatial frequency LIPSS (LSFL) with an anomalous orientation parallel to the laser polarization. Based on this input, we performed finite-difference time-domain calculations considering a layered system resembling the geometry of the HSFL along with the presence of a laser-induced oxide layer. The simulations support a scenario that the new type of LSFL is formed at the interface between the laser-induced oxide layer and the non-altered material underneath. These findings suggest that LSFL structures parallel to the polarization can be easily induced in materials that are prone to oxidation. KW - Laser-induced oxide layer KW - Laser-induced periodic surface structures (LIPSS) KW - Surface chemistry KW - Femtosecond laser processing KW - Nanostructuring PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502530 DO - https://doi.org/10.3390/nano10010147 SN - 2079-4991 VL - 10(1) IS - Special issue "Laser-generated periodic nanostructures" SP - 147-1 EP - 147-18 PB - MDPI CY - Basel AN - OPUS4-50253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cubero, A. A1 - Martínez, E. A1 - Angurel, L.A. A1 - de la Fuente, G.F. A1 - Navarro, R. A1 - Legall, Herbert A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Effects of laser-induced periodic surface structures on the superconducting properties of Niobium N2 - It is well known that the use of ultrashort (fs) pulsed lasers can induce the generation of (quasi-) periodic nanostructures (LIPSS, ripples) on the surface of many materials. Such nanostructures have also been observed in sample’s surfaces irradiated with UV lasers with a pulse duration of 300 ps. In this work, we compare the characteristics of these nanostructures on 1-mm and on 25-μm thick niobium sheets induced by 30 fs n-IR and 300 ps UV pulsed lasers. In addition to conventional continuous or burst mode processing configurations, two-dimensional laser beam and line scanning modes have been investigated in this work. The latter allows the processing of large areas with a more uniform distribution of nanostructures at the surface. The influence of the generated nanostructures on the superconducting properties of niobium has also been explored. For this aim, magnetic hysteresis loops have been measured at different cryogenic temperatures to analyse how these laser treatments affect the flux pinning behaviour and, in consequence, the superconductor’s critical current values. It was observed that laser treatments are able to modify the superconducting properties of niobium samples. T2 - E-MRS Spring Meeting 2019 CY - Nice, France DA - 27.05.2019 KW - Superconductivity KW - Laser-induced periodic surface structures (LIPSS) KW - Niobium PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502541 DO - https://doi.org/10.1016/j.apsusc.2019.145140 SN - 0169-4332 SN - 1873-5584 VL - 508 IS - 1 SP - 145140-1 EP - 145140-7 PB - Elsevier CY - Amsterdam AN - OPUS4-50254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Florian, Camilo A1 - Fischer, Daniel A1 - Freiberg, K. A1 - Duwe, M. A1 - Sahre, Mario A1 - Schneider, S. A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Rettenmayr, M. A1 - Beck, Uwe A1 - Undisz, A. A1 - Bonse, Jörn T1 - Single Femtosecond Laser-Pulse-Induced Superficial Amorphization and Re-Crystallization of Silicon N2 - Superficial amorphization and re-crystallization of silicon in <111> and <100> orientation after irradiation by femtosecond laser pulses (790 nm, 30 fs) are studied using optical imaging and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) allows fast data acquisition at multiple wavelengths and provides experimental data for calculating nanometric amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. For a radially Gaussian laser beam and at moderate peak fluences above the melting and below the ablation thresholds, laterally parabolic amorphous layer profiles with maximum thicknesses of several tens of nanometers were quantitatively attained. The accuracy of the calculations is verified experimentally by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the superficial re-solidification of silicon after local melting by femtosecond laser pulses is drawn. KW - Femtosecond laser KW - Silicon KW - Amorphization KW - Crystallization KW - Spectroscopic imaging ellipsometry PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523687 UR - https://www.mdpi.com/1996-1944/14/7/1651 DO - https://doi.org/10.3390/ma14071651 SN - 1996-1944 VL - 14 IS - 7 SP - 1651-1 EP - 1651-21 PB - MDPI AG CY - Basel, Switzerland AN - OPUS4-52368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tsibidis, G. D. A1 - Mimidis, A. A1 - Skoulas, E. A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Stratakis, E. T1 - Modelling periodic structure formation on 100Cr6 steel after irradiation with femtosecond-pulsed laser beams N2 - We investigate the periodic structure formation upon intense femtosecond pulsed irradiation of chrome steel (100Cr6) for linearly polarised laser beams. The underlying physical mechanism of the laser-induced periodic structures is explored, their spatial frequency is calculated and theoretical results are compared with experimental observations. The proposed theoretical model comprises estimations of electron excitation, heat transfer, relaxation processes, and hydrodynamics-related mass transport. Simulations describe the sequential formation of sub-wavelength ripples and supra-wavelength grooves. In addition, the influence of the laser wavelength on the periodicity of the structures is discussed. The proposed theoretical investigation offers a systematic methodology towards laser processing of steel surfaces with important applications. KW - Laser-induced periodic surface structures KW - Femtosecond laser ablation KW - Steel PY - 2018 UR - https://link.springer.com/article/10.1007/s00339-017-1443-y DO - https://doi.org/10.1007/s00339-017-1443-y SN - 0947-8396 SN - 1432-0630 VL - 124 IS - 1 SP - 27, 1 EP - 13 PB - Springer-Verlag AN - OPUS4-43626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seuthe, T. A1 - Mermillod-Blondin, A. A1 - Grehn, M. A1 - Bonse, Jörn A1 - Wondraczek, L. A1 - Eberstein, M. T1 - Structural relaxation phenomena in silicate glasses modifed by irradiation with femtosecond laser pulses N2 - Structural relaxation phenomena in binary and multicomponent lithium silicate glasses were studied upon irradiation with femtosecond (fs) laser pulses (800 nm central wavelength, 130 fs pulse duration) and subsequent thermal annealing experiments. Depending on the annealing temperature, micro-Raman spectroscopy analyses evidenced different relaxation behaviours, associated to bridging and non-bridging oxygen structures present in the glass network. The results indicate that the mobility of lithium ions is an important factor during the glass modification with fs-laser pulses. Quantitative phase contrast imaging (spatial light interference microscopy) revealed that these fs-laser induced structural modifications are closely related to local changes in the refractive index of the material. The results establish a promising strategy for tailoring fs-laser sensitivity of glasses through structural mobility. KW - Femtosecond laser KW - Silicate glasses KW - Raman spectroscopy KW - Structural relaxation KW - Refractive index PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393045 DO - https://doi.org/10.1038/srep43815 SN - 2045-2322 VL - 7 SP - 43815, 1 EP - 43815, 10 PB - Nature Publishing Group CY - London, UK AN - OPUS4-39304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Höhm, S. A1 - Epperlein, Nadja A1 - Spaltmann, Dirk A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Applications of laser-induced periodic surface structures (LIPSS) N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the picosecond to femtosecond range. During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical or chemical properties. In this contribution current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting, the tailoring of surface colonization by bacterial biofilms, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - SPIE Photonics West Conference, Laser-based Micro- and Nanoprocessing XI CY - San Francisco, USA DA - 27.01.2017 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Surface functionalization KW - Application PY - 2017 SN - 978-1-5106-0625-8 SN - 978-1-5106-0626-5 DO - https://doi.org/10.1117/12.2250919 SN - 0277-786X SN - 1996-756X VL - 10092 SP - Article UNSP 100920N, 100920N-1 EP - 100920N-9 PB - SPIE CY - Bellingham, USA AN - OPUS4-39305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Kirner, Sabrina A1 - Koter, Robert A1 - Pentzien, Simone A1 - Spaltmann, Dirk A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures on titanium nitride coatings for tribological applications N2 - Titanium nitride (TiN) was coated on different substrate materials, namely pure titanium (Ti), titanium alloy (Ti6Al4V) and steel (100Cr6), generating 2.5 μm thick TiN layers. Using femtosecond laser pulses (30 fs, 790 nm, 1 kHz pulse repetition rate), large surface areas (5 mm × 5 mm) of laser-induced periodic surface structures (LIPSS) with sub-wavelength periods ranging between 470 nm and 600 nm were generated and characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). In tribological tests, coefficients of friction (COF) of the nanostructured surfaces were determined under reciprocating sliding conditions (1 Hz, 1.0 N normal load) against a 10-mm diameter ball of hardened 100Cr6 steel during 1000 cycles using two different lubricants, namely paraffin oil and engine oil. It turned out that the substrate material, the laser fluence and the lubricant are crucial for the tribological performance. However, friction and wear could not be significantly reduced by LIPSS on TiN layers in comparison to unstructured TiN surfaces. Finally, the resulting wear tracks on the nanostructured surfaces were investigated with respect to their morphology (OM, SEM), depth (WLIM) and chemical composition by energy dispersive X-ray spectroscopy (EDX) and, on one hand, compared with each other, on the other hand, with non-structured TiN surfaces. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Titanium nitride films KW - Friction KW - Wear PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0169433216322486 DO - https://doi.org/10.1016/j.apsusc.2016.10.132 SN - 0169-4332 SN - 1873-5584 VL - 418 IS - Part B SP - 572 EP - 579 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-40507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hermens, U. A1 - Kirner, Sabrina A1 - Emonts, C. A1 - Comanns, P. A1 - Skoulas, E. A1 - Mimidis, A. A1 - Mescheder, H. A1 - Winands, K. A1 - Krüger, Jörg A1 - Stratakis, E. A1 - Bonse, Jörn T1 - Mimicking lizard-like surface structures upon ultrashort laser pulse irradiation of inorganic materials N2 - Inorganic materials, such as steel, were functionalized by ultrashort laser pulse irradiation (fs- to ps-range) to modify the surface’s wetting behavior. The laser processing was performed by scanning the laser beam across the surface of initially polished flat sample material. A systematic experimental study of the laser processing parameters (peak fluence, scan velocity, line overlap) allowed the identification of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, grooves, spikes, etc.). Analyses of the surface using optical as well as scanning electron microscopy revealed morphologies providing the optimum similarity to the natural skin of lizards. For mimicking skin structures of moisture-harvesting lizards towards an optimization of the surface wetting behavior, additionally a two-step laser processing strategy was established for realizing hierarchical microstructures. In this approach, micrometer-scaled capillaries (step 1) were superimposed by a laser-generated regular array of small dimples (step 2). Optical focus variation imaging measurements finally disclosed the three dimensional topography of the laser processed surfaces derived from lizard skin structures. The functionality of these surfaces was analyzed in view of wetting properties. KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures KW - Lizard KW - Surface wetting KW - Fluid transport KW - Steel PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0169433216328306 DO - https://doi.org/10.1016/j.apsusc.2016.12.112 SN - 0169-4332 SN - 1873-5584 VL - 418 IS - Part B SP - 499 EP - 507 PB - Elsevier, North-Holland CY - Amsterdam AN - OPUS4-40509 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ringleb, F. A1 - Eylers, K. A1 - Teubner, T. A1 - Schramm, H.-P. A1 - Symietz, Christian A1 - Bonse, Jörn A1 - Andree, Stefan A1 - Heidmann, B. A1 - Schmid, M. A1 - Krüger, Jörg A1 - Boeck, T. T1 - Growth and shape of indium islands on molybdenum at micro-roughened spots created by femtosecond laser pulses N2 - Indium islands on molybdenum coated glass can be grown in ordered arrays by surface structuring using a femtosecond laser. The effect of varying the molybdenum coated glass substrate temperature and the indium deposition rate on island areal density, volume and geometry is investigated and evaluated in a physical vapor deposition (PVD) process. The joined impact of growth conditions and spacing of the femtosecond laser structured spots on the arrangement and morphology of indium islands is demonstrated. The results yield a deeper understanding of the island growth and its precise adjustment to industrial requirements, which is indispensable for a technological application of such structures at a high throughput, for instance as precursors for the preparation of Cu(In,Ga)Se2 micro concentrator solar cells. KW - Indium islands KW - Femtosecond laser patterning KW - Diffusion KW - CIGSe micro solar cells PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0169433216325764 DO - https://doi.org/10.1016/j.apsusc.2016.11.135 SN - 0169-4332 SN - 1873-5584 VL - 418 SP - 548 EP - 553 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-40551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epperlein, Nadja A1 - Menzel, Friederike A1 - Schwibbert, Karin A1 - Koter, Robert A1 - Bonse, Jörn A1 - Sameith, Janin A1 - Krüger, Jörg A1 - Toepel, Jörg T1 - Influence of femtosecond laser produced nanostructures on biofilm growth on steel N2 - Biofilm formation poses high risks in multiple industrial and medical settings. However, the robust nature of biofilms makes them also attractive for industrial applications where cell biocatalysts are increasingly in use. Since tailoring material properties that affect bacterial growth or its inhibition is gaining attention, here we focus on the effects of femtosecond laser produced nanostructures on bacterial adhesion. Large area periodic surface structures were generated on steel surfaces using 30-fs laser pulses at 790 nm wavelength. Two types of steel exhibiting a different corrosion resistance were used, i.e., a plain structural steel (corrodible) and a stainless steel (resistant to corrosion). Homogeneous fields of laser-induced periodic surface structures (LIPSS) were realized utilizing laser fluences close to the ablation threshold while scanning the sample under the focused laser beam in a multi-pulse regime. The nanostructures were characterized with optical and scanning electron microscopy. For each type of steel, more than ten identical samples were laser-processed. Subsequently, the samples were subjected to microbial adhesion tests. Bacteria of different shape and adhesion behavior (Escherichia coli and Staphylococcus aureus) were exposed to laser structures and to polished reference surfaces. Our results indicate that E. coli preferentially avoids adhesion to the LIPSS-covered areas, whereas S. aureus favors these areas for colonization. KW - Laser-induced periodic surface structures KW - Femtosecond laser KW - Steel KW - Biofilms KW - Microbial adhesion tests PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0169433217305470 DO - https://doi.org/10.1016/j.apsusc.2017.02.174 SN - 0169-4332 SN - 1873-5584 VL - 418 IS - Part B SP - 420 EP - 424 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-40565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ringleb, F. A1 - Andree, Stefan A1 - Heidmann, B. A1 - Bonse, Jörn A1 - Eylers, K. A1 - Ernst, O. A1 - Boeck, T. A1 - Schmid, M. A1 - Krüger, Jörg T1 - Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics N2 - Micro-concentrator solar cells offer an attractive way to further enhance the efficiency of planar-cell technologies while saving absorber material. Here, two laser-based bottom-up processes for the fabrication of regular arrays of CuInSe2 and Cu(In,Ga)Se2 microabsorber islands are presented, namely one approach based on nucleation and one based on laser-induced forward transfer. Additionally, a procedure for processing these microabsorbers to functioning micro solar cells connected in parallel is demonstrated. The resulting cells show up to 2.9% efficiency and a significant efficiency enhancement under concentrated Illumination. KW - Chalcopyrite KW - Femtosecond laser patterning KW - Laser-induced forward transfer KW - Micro-concentrator solar cell KW - Photovoltaics PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470026 DO - https://doi.org/10.3762/bjnano.9.281 SN - 2190-4286 VL - 9 SP - 3025 EP - 3038 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, M. AN - OPUS4-47002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kirner, Sabrina V. A1 - Hermens, U. A1 - Mimidis, A. A1 - Skoulas, E. A1 - Florian, C. A1 - Hischen, F. A1 - Plamadeala, C. A1 - Baumgartner, W. A1 - Winands, K. A1 - Mescheder, H. A1 - Krüger, Jörg A1 - Solis, J. A1 - Siegel, J. A1 - Stratakis, E. A1 - Bonse, Jörn T1 - Mimicking bug-like surface structures and their fluid transport produced by ultrashort laser pulse irradiation of steel N2 - Ultrashort laser pulses with durations in the fs-to-ps range were used for large area surface processing of steel aimed at mimicking the morphology and extraordinary wetting behaviour of bark bugs (Aradidae) found in nature. The processing was performed by scanning the laser beam over the surface of polished flat sample surfaces. A systematic variation of the laser processing parameters (peak fluence and effective number of pulses per spot diameter) allowed the identification of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, i.e., LIPSS, grooves, spikes, etc.). Moreover, different laser processing strategies, varying laser wavelength, pulse duration, angle of incidence, irradiation atmosphere, and repetition rates, allowed to achieve a range of morphologies that resemble specific structures found on bark bugs. For identifying the ideal combination of parameters for mimicking bug-like structures, the surfaces were inspected by scanning electron microscopy. In particular, tilted micrometre-sized spikes are the best match for the structure found on bark bugs. Complementary to the morphology study, the wetting behaviour of the surface structures for water and oil was examined in terms of philic/ phobic nature and fluid transport. These results point out a route towards reproducing complex surface structures inspired by nature and their functional response in technologically relevant materials. KW - Biomometics KW - Surface wetting KW - Steel KW - Bug KW - Laser-induced periodic surface structures KW - Fluid transport KW - Femtosecond laser ablation PY - 2017 DO - https://doi.org/10.1007/s00339-017-1317-3 SN - 0947-8396 SN - 1432-0630 VL - 123 IS - 12 SP - 754, 1 EP - 13 AN - OPUS4-42817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heitz, J. A1 - Plamadeala, C. A1 - Muck, M. A1 - Armbruster, O. A1 - Baumgartner, W. A1 - Weth, A. A1 - Steinwender, C. A1 - Plessberger, H. A1 - Kellermair, J. A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Guntner, A. S. A1 - Hassel, A. W. T1 - Femtosecond laser-induced microstructures on Ti substrates for reduced cell adhesion N2 - Miniaturized pacemakers with a surface consisting of a Ti alloy may have to be removed after several years from their implantation site in the heart and shall, therefore, not be completely overgrown by cells or tissue. A method to avoid this may be to create at the surface by laser-ablation self-organized sharp conical spikes, which provide too little surface for cells (i.e., fibroblasts) to grow on. For this purpose, Ti-alloy substrates were irradiated in the air by 790 nm Ti:sapphire femtosecond laser pulses at fluences above the ablation threshold. The laser irradiation resulted in pronounced microstructure formation with hierarchical surface morphologies. Murine fibroblasts were seeded onto the laser-patterned surface and the coverage by cells was evaluated after 3–21 days of cultivation by means of scanning electron microscopy. Compared to flat surfaces, the cell density on the microstructures was significantly lower, the coverage was incomplete, and the cells had a clearly different morphology. The best results regarding suppression of cell growth were obtained on spike structures which were additionally electrochemically oxidized under acidic conditions. Cell cultivation with additional shear stress could reduce further the number of adherent cells. KW - Laser Processing KW - Femtosecond laser KW - Titanium alloy KW - Cell adhesion KW - Anodic oxidation KW - Pacemaker PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427681 UR - https://link.springer.com/article/10.1007/s00339-017-1352-0 DO - https://doi.org/10.1007/s00339-017-1352-0 SN - 0947-8396 SN - 1432-0630 VL - 123 IS - 12 SP - 734, 1 EP - 9 PB - Springer-Verlag CY - Berlin AN - OPUS4-42768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andree, Stefan A1 - Heidmann, B. A1 - Ringleb, F. A1 - Eylers, K. A1 - Bonse, Jörn A1 - Boeck, T. A1 - Schmid, M. A1 - Krüger, Jörg T1 - Production of precursors for micro-concentrator solar cells by femtosecond laser-induced forward transfer N2 - Single-pulse femtosecond laser-induced forward transfer (LIFT, 30 fs, 790 nm) is used to deposit micron-sized dots of copper and/or indium onto a molybdenum layer on glass. Such systems can serve as precursors for the bottom-up manufacturing of micro-concentrator solar cells based on copper-indium-gallium-diselenide. The influence of the thickness of the copper, indium and combined copper-indium donor layers on the quality of the transferred dots was qualified by scanning electron microscopy, energy-dispersive X-ray analysis, and optical microscopy. The potential for manufacturing of a spatial arrangement adapted to the geometry of micro-lens arrays needed for micro-concentrator solar cells is demonstrated. T2 - EMRS Spring Meeting 2017, Symposium X “New frontiers in laser interaction: from hard coatings to smart materials" CY - Strasbourg, France DA - 22.05.2017 KW - Laser-induced forward transfer (LIFT) KW - Femtosecond laser KW - Micro-concentrator solar cell KW - Copper-indium-gallium-diselenide KW - CIGSe PY - 2017 DO - https://doi.org/10.1007/s00339-017-1282-x SN - 1432-0630 SN - 0947-8396 VL - 123 SP - Article 670, 1 EP - 8 AN - OPUS4-42273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn T1 - Scattering on scattering N2 - Ultrafast experiments can reveal the spatiotemporal dynamics of nanostructure formation via scattering in background-free optical dark-field microscopy. KW - Ultrafast microscopy KW - Scattering KW - Darkfield microscopy KW - Laser ablation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411596 DO - https://doi.org/10.1038/lsa.2017.88 SN - 2047-7538 VL - 6 SP - e17088, 1 EP - 2 PB - Springer Nature AN - OPUS4-41159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudenko, A. A1 - Colombier, J.-P. A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Itina, T.E. T1 - Spontaneous periodic ordering on the surface and in the bulk of dielectrics irradiated by ultrafast laser: a shared electromagnetic origin N2 - Periodic self-organization of matter beyond the diffraction limit is a puzzling phenomenon, typical both for surface and bulk ultrashort laser processing. Here we compare the mechanisms of periodic nanostructure formation on the surface and in the bulk of fused silica. We show that volume nanogratings and surface nanoripples having subwavelength periodicity and oriented perpendicular to the laser polarization share the same electromagnetic origin. The nanostructure orientation is defined by the near-field local enhancement in the vicinity of the inhomogeneous scattering centers. The periodicity is attributed to the coherent superposition of the waves scattered at inhomogeneities. Numerical calculations also support the multipulse accumulation nature of nanogratings formation on the surface and inside fused silica. Laser surface processing by multiple laser pulses promotes the transition from the high spatial frequency perpendicularly oriented nanoripples to the low spatial frequency ripples, parallel or perpendicular to the laser polarization. The latter structures also share the electromagnetic origin, but are related to the incident field interference with the scattered far-field of rough non-metallic or transiently metallic surfaces. The characteristic ripple appearances are predicted by combined electromagnetic and thermo-mechanical approaches and supported by SEM images of the final surface morphology and by time-resolved pump-probe diffraction measurements. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Nanostructures KW - Dielectrics KW - Electromagnetic scattering PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-421747 UR - https://www.nature.com/articles/s41598-017-12502-4 DO - https://doi.org/10.1038/s41598-017-12502-4 SN - 2045-2322 VL - 7 SP - Article 12306, 1 EP - 14 PB - Springer Nature AN - OPUS4-42174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Peláez, R.J. A1 - Rebollar, E. A1 - Serna, R. A1 - Acosta-Zepeda, C. A1 - Saavedra, P. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Nanosecond laser-induced interference grating formation on silicon N2 - The formation of gratings on the surface of a silicon wafer by nanosecond laser irradiation through a phase mask using an ArF laser emitting at 193 nm is studied. The phase mask along with some focusing optics is capable to generate via interference a periodic intensity distribution, which can be used for surface patterning. The surface patterning strongly depends on the laser energy density and on the number of pulses, as revealed by atomic force microscopy (AFM). The results show that irradiation even with a single laser pulse produces periodic depth modulations on the surface. The spatial surface modulation is in the micrometer (1.7 µm) range while the depth modulation is in the nanometer regime (1–20 nm). With an increasing number of pulses (1–100), the depth modulation amplitude increases smoothly. Increasing the number of pulses further results in the progressive destruction of the grating, vanishing completely after ~5000 pulses. This evolution is also monitored in situ by measuring the intensity of the first order-diffracted probe beam and the behavior is in accordance with what is observed by AFM. Finally, we qualitatively explain the results invoking thermally induced effects in the melted Si: these physical processes involved are probably thermocapillary and/or Marangoni effects inducing material displacement as the surface melts. KW - Nanosecond laser irradiation KW - Silicon KW - Surface modification KW - Phase mask KW - Grating PY - 2019 UR - https://iopscience.iop.org/article/10.1088/1361-6463/ab0c5f DO - https://doi.org/10.1088/1361-6463/ab0c5f SN - 1361-6463 SN - 0022-3727 VL - 52 IS - 22 SP - 225302, 1 EP - 10 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-47619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray emission during ultrashort pulse laser processing N2 - The industrial use of ultrashort laser pulses has made considerable progress in recent years. The reasons for this lie in the availability of high average powers at pulse repetition rates in the several 100 kHz range. The advantages of using ultrashort laser pulses in terms of processing precision can thus be fully exploited. However, high laser intensities on the workpiece can also lead to the generation of unwanted X-rays. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose can become significant for high-repetition-rate laser systems so that X-ray exposure safety limits must be considered. The X-ray emission during ultrashort pulse laser processing was investigated for a pulse duration of 925 fs at 1030 nm wavelength and 400 kHz repetition rate. Industrially relevant materials such as steel,aluminum and glass were treated. Tungsten served as reference. X-ray spectra were recorded, and X-ray dose measurements were performed for laser treatment in air. For laser intensities > 2 × 10^13 W/cm2, X-ray doses exceeding the regulatory exposure limits for members of the public were found. Suitable X-ray protection strategies are proposed. T2 - SPIE Photonics West CY - San Francisco, USA DA - 02.02.2019 KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Radiation protection PY - 2019 SN - 978-1-5106-2459-7 DO - https://doi.org/10.1117/12.2516165 SN - 0277-786X SN - 1996-756X VL - 10908 SP - 1090802-1 EP - 1090802-7 PB - SPIE - The international society for optics and photonics CY - Bellingham, WA, USA AN - OPUS4-47510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Acosta-Zepeda, C. A1 - Saavedra, P. A1 - Bonse, Jörn A1 - Haro-Poniatowski, E. T1 - Modeling of silicon surface topographies induced by single nanosecond laser pulse induced melt-flows N2 - Irradiation with a single nanosecond laser pulse in the melting regime can result in a characteristic change in the surface morphology of crystalline silicon. This has been verified experimentally in a variety of situations, where dimple-shaped surface topographies are produced. In this work, the dimple height, depth, and width are modeled following and extending in a more rigorous manner the approach of Wood and Giles [Phys. Rev. B 23, 2923–2942 (1981)] and that of Schwarz-Selinger and coworkers [Phys. Rev. B 64, 155323 (2001)], upon varying the laser irradiation parameters such as peak energy density, pulse duration, and wavelength. This is achieved with numerical simulations of one-dimensional heat flow as input to the analytical fluid-flow equations. KW - Nanosecond laser KW - Melting KW - Silicon KW - Fluid-flow PY - 2019 DO - https://doi.org/10.1063/1.5053918 SN - 0021-8979 SN - 1089-7550 VL - 125 IS - 17 SP - 175101-1 EP - 175101-9 PB - AIP Publishing CY - Melville, USA AN - OPUS4-47927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolff, M. A1 - Wonneberger, R. A1 - Freiberg, K.E. A1 - Hertwig, Andreas A1 - Bonse, Jörn A1 - Giebeler, L. A1 - Koitzsch, A. A1 - Kunz, C. A1 - Weber, H. A1 - Hufenbach, J.K. A1 - Müller, F.A. A1 - Gräf, S. T1 - Formation of laser-induced periodic surface structures on Zr-based bulk metallic glasses with different chemical composition N2 - Bulk metallic glasses (BMG) are amorphous metal alloys known for their unique physical and mechanical properties. In the present study, the formation of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on the Zr-based BMGs Zr46Cu46Al8, Zr61Cu25Al12Ti2, Zr52.5Cu17.9Al10Ni14.6Ti5 (Vit105) and Zr57Cu15.4Al10Ni12.6Nb5 (Vit106) was investigated as a function of their different chemical composition. For this purpose, LIPSS were generated on the sample surfaces in an air environment by fs-laser irradiation (λ = 1025 nm, τ = 300 fs, frep = 100 kHz). The surface topography was characterized by scanning electron microscopy and atomic force microscopy. Moreover, the impact of LIPSS formation on the structure and chemical surface composition was analyzed before and after fs-laser irradiation by X-ray diffraction and X-ray photoelectron spectroscopy as well as by transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. Despite the different chemical composition of the investigated BMGs, the fs-laser irradiation resulted in almost similar properties of the generated LIPSS patterns. In the case of Zr61Cu25Al12Ti2, Vit105 and Vit106, the surface analysis revealed the preservation of the amorphous state of the materials during fs-laser irradiation. The study demonstrated the presence of a native oxide layer on all pristine BMGs. In addition, fs-laser irradiation results in the formation of laser-induced oxide layers of larger thickness consisting of an amorphous ZrAlCu-oxide. The precise laser-structuring of BMG surfaces on the nanoscale provides a versatile alternative to thermoplastic forming of BMG surfaces and is of particular interest for the engineering of functional material surfaces. KW - Bulk metallic glasses KW - Femtosecond laser KW - Laser-induced periodic surface structures (LIPSS) KW - Chemical analysis KW - Oxidation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581799 DO - https://doi.org/10.1016/j.surfin.2023.103305 SN - 2468-0230 VL - 42 SP - 1 EP - 11 PB - Elsevier B.V. AN - OPUS4-58179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Richter, Anja M. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Laser-Textured Surfaces: A Way to Control Biofilm Formation? N2 - Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria-repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria-repellent surfaces lies in the contactless and aseptic large-area laser-processing of technical surfaces. Tailored surface textures, enabled by different laser-processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state-of-the-art review of laser-surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser-processed surfaces, the challenges of anti-microbial surface designs are discussed, and future directions will be outlined. KW - Antibacterial surfaces KW - Biofilms KW - Laser processing KW - Laser-induced periodic surface structures (LIPSS) KW - Microbial adhesions PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588260 DO - https://doi.org/10.1002/lpor.202300753 SN - 1863-8899 SP - 1 EP - 41 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraft, Sebastian A1 - Schille, J. A1 - Bonse, Jörn A1 - Löschner, U. A1 - Krüger, Jörg T1 - X‑ray emission during the ablative processing of biological materials by ultrashort laser pulses N2 - The ablative laser processing with ultrashort pulsed laser beams may cause secondary emission of hazardous X-rays. While the effect has recently been proven to be considered in working safety regulations when processing technical materials, such as metals, the X-ray emission rates during the ablative processing of biological tissue materials are widely unexplored yet. Therefore, biological materials like water, isotonic saline solution, pig eyes, and human teeth were ablated with ultrashort laser pulses of 1030 nm wavelength, 600 fs pulse duration and 5 kHz pulse repetition rate, aiming to mimic typical surgery situations. Simultaneously, in-situ X-ray dose rate measurements were performed at a short distance from the plasma to display potential X-ray emission. For all four studied biological materials, our measurements prove the secondary emission of laser-induced X-rays. KW - Ultrashort pulsed laser KW - Laser-induced X-ray emission KW - Ophthalmology KW - Dentistry KW - Secondary hazard PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569960 DO - https://doi.org/10.1007/s00339-023-06440-4 SN - 0947-8396 VL - 129 IS - 3 SP - 1 EP - 8 PB - Springer AN - OPUS4-56996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Costache, F. A1 - Valette, S. A1 - Bonse, Jörn T1 - Editorial: Special Issue “Dynamics and Processes at Laser-Irradiated Surfaces—A Themed Issue in Honor of the 70th Birthday of Professor Jürgen Reif” N2 - The Special Issue “Dynamics and Processes at Laser-irradiated Surfaces” is dedicated to the 70th birthday of Jürgen Reif, retired full professor, former Chair of Experimental Physics II of the Faculty of Physics of the Brandenburg University of Technology Cottbus—Senftenberg in Germany. KW - Laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Femtosecond laser PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569482 DO - https://doi.org/10.3390/nano13030611 SN - 2079-4991 VL - 13 IS - 3 SP - 1 EP - 3 PB - MDPI CY - Basel AN - OPUS4-56948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Editorial: Special Issue “Advanced Pulse Laser Machining Technology" N2 - “Advanced Pulse Laser Machining Technology” is a rapidly growing field that can be tailored to special industrial and scientific applications. This is significantly driven by the availability of high-repetition-rate laser sources and novel beam delivery concepts. KW - Editorial KW - Pulse Laser KW - Laser Machining KW - Ultrashort laser pulses PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568410 DO - https://doi.org/10.3390/ma16020819 SN - 1996-1944 VL - 16 IS - 2 SP - 1 EP - 4 PB - MDPI CY - Basel AN - OPUS4-56841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Sokolowski‐Tinten, Klaus T1 - Probing Laser‐Driven Structure Formation at Extreme Scales in Space and Time N2 - Irradiation of solid surfaces with high intensity, ultrashort laser pulses triggers a variety of secondary processes that can lead to the formation of transient and permanent structures over a large range of length scales from mm down to the nano‐range. One of the most prominent examples are LIPSS – Laser‐Induced Periodic Surface Structures. While LIPSS have been a scientific evergreen for of almost 60 years, experimental methods that combine ultrafast temporal with the required nm spatial resolution have become available only recently with the advent of short pulse, short wavelength free electron lasers. Here, the current status and future perspectives in this field are discussed by exploiting the unique possibilities of these 4th‐generation light sources to address by time‐domain experimental techniques the fundamental LIPSS‐question, namely why and how laser irradiation can initiate the transition of a “chaotic” (rough) surface from an aperiodic into a periodic structure. KW - Laser-induced periodic surface structures (LIPSS) KW - Free electron laser KW - Pump-probe experiments KW - Time-resolved scattering KW - Capillary waves PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595048 DO - https://doi.org/10.1002/lpor.202300912 SN - 1863-8899 VL - 18 SP - 1 EP - 11 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-59504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, Y. A1 - Gruner, A. A1 - Aboud, D. G. K. A1 - Bonse, Jörn A1 - Schille, J. A1 - Loeschner, U. A1 - Kietzig, A.-M. T1 - Polarization effects on laser-inscribed angled micro-structures N2 - The polarization of the laser beam exhibits more substantial differences in laser micromachining as the angle of incidence deviates from zero. In the reported work, our focus was to explore the effects of circularly, p- and s-polarized laser on angled ultrashort pulse laser micromachining of micropillar arrays. The examination encompassed laser process factors, including angles of incidence, microstructure dimensions, and inter-pillar spacing. A comparison between the resulting structures demonstrated that p-polarized laser beam was the most efficient in material removal in angled laser micromachining, followed by circularly polarized laser. While the s-polarized beam exhibited the lowest ablation efficiency among the three. Such distinction is mainly attributed to the distinguishing reflectivity of the three states of polarization on tilted planes. The development of structural heights during ablation processes was examined, and potential defects in laser processing methodologies were interpreted. The dependency of structural heights on inter-pillar spacing was analyzed. This study bridges the gap between existing studies on angled ultrashort pulse laser machining and the influences of polarization on laser machining. The comparison between structures produced using laboratory-scale and industrial-scale laser systems also yielded pertinent recommendations for facilitating a smooth transition of angled laser micromachining from laboratory-scale research to industrial applications. KW - Laser processing KW - Laser-induced periodic surface structures (LIPSS) KW - Microstructures KW - Nanostructures PY - 2024 UR - https://www.sciencedirect.com/science/article/pii/S0169433223028714 DO - https://doi.org/10.1016/j.apsusc.2023.159191 SN - 0169-4332 VL - 649 SP - 1 EP - 15 PB - Elsevier AN - OPUS4-59329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Porta-Velilla, L. A1 - Martínez, E. A1 - Frechilla, A. A1 - Castro, M. A1 - de la Fuente, G. F. A1 - Bonse, Jörn A1 - Angurel, L. A. T1 - Grain orientation, angle of incidence, and beam polarization effects on ultraviolet 300 ps-laser-induced nanostructures on 316L stainless steel N2 - Laser-induced periodic surface structures (LIPSS) represent a unique route for functionalizing materials through the fabrication of surface nanostructures. Commercial AISI 316L stainless steel (SS316L) surfaces are laser treated by ultraviolet 300 ps laser pulses in a laser line scanning (LLS) approach. Processing parameters are optimized (pulse energy of 2.08 µJ, pulse repetition frequency of 300 kHz, and suitable laser scan and sample displacement rates) for the generation of low spatial frequency LIPSS over a large 25 × 25 mm2 area. Different angles of incidence of the laser radiation (0°, 30°, and 45°) and different linear laser beam polarizations (s and p) produce a plethora of rippled surface morphologies at distinct grains. Scanning electron microscopy and 2D Fourier transforms, together with calculations of the optical energy deposited at the treated surfaces using Sipe's first-principles electromagnetic scattering theory, are used to study and analyze in detail these surface morphologies. Combined with electron backscattering diffraction, analyses allow associating site-selectively various laser-induced-surface morphologies with the underlying crystalline grain orientation. Resulting grain orientation maps reveal a strong impact of the grain crystallographic orientation on LIPSS formation and point toward possible strategies, like multi-step processes, for improving the manufacturing of LIPSS and their areal coverage of polycrystalline technical materials. KW - Laser-induced periodic surface structures (LIPSS) KW - Steel KW - Grain orientation KW - Electron backscattering diffraction (EBSD) KW - Laser processing PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588929 DO - https://doi.org/10.1002/lpor.202300589 SN - 1863-8899 SP - 1 EP - 21 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Sturm, Heinz A1 - Schmidt, Dieter A1 - Kautek, Wolfgang T1 - Chemical, morphological and accumulation phenomena in ultrashort-pulse laser ablation of TiN in air N2 - Ultrashort-pulse laser ablation (F=130 fs, 5=800 nm, repetition rate 2-20 Hz) of titanium nitride was investigated for laser fluences between 0.3 and 4.5 J/cm2 using the direct focusing technique in air. The influence of the laser pulse number and the peak fluence was investigated by means of several surface analytical techniques (optical microscopy, dynamic friction atomic force microscopy, scanning Auger electron microscopy and small-spot electron spectroscopy for chemical analysis). The correlation of the results about optical, physical and chemical properties of the irradiated areas allows us to propose a simple oxidation model, which explains different observed phenomena associated with surface damage such as mound formation and crater widening and clarifies the incubation behavior reported earlier for this material. PY - 2000 DO - https://doi.org/10.1007/s003390000585 SN - 0947-8396 VL - 71 IS - 6 SP - 657 EP - 665 PB - Springer CY - Berlin AN - OPUS4-1067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Bachelier, G. A1 - Siegel, J. A1 - Solis, J. A1 - Sturm, Heinz T1 - Time- and space-resolved dynamics of ablation and optical breakdown induced by femtosecond laser pulses in indium phosphide N2 - Femtosecond time-resolved microscopy has been used to analyze the structural transformation dynamics (melting, ablation, and solidification phenomena) induced by single intense 130 fs laser pulses in single-crystalline (100)-indium phosphide wafers in air on a time scale from ~100 fs up to 8 ns. In the ablative regime close to the ablation threshold, transient surface reflectivity patterns are observed by fs microscopy on a ps to ns time scale as a consequence of the complex spatial density structure of the ablating material (dynamic Newton fringes). At higher fluences, exceeding six times the ablation threshold, optical breakdown causes another, more violent ablation regime, which reduces the energy deposition depth along with the time of significant material removal. As a consequence, ablation lasts longer in a ring-shaped region around the region of optical breakdown. This leads to the formation of a crater profile with a central protrusion. In the melting regime below the ablation threshold, the melting dynamics of indium phosphide has been quantified and subsequent superficial amorphization has been observed upon solidification on the ns time scale leading to amorphous layer thicknesses of the order of a few tens of nanometers. KW - Femtosecond laser pulse KW - Indium Phosphide KW - Ablation KW - Surface reflectivity KW - Fs-time resolved microscopy KW - Scanning Force Microscopy PY - 2008 DO - https://doi.org/10.1063/1.2885105 SN - 0021-8979 SN - 1089-7550 VL - 103 IS - 5 SP - 054910-1 EP - 054910-6 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-17090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Bachelier, G. A1 - Wiggins, S. M. A1 - Siegel, J. A1 - Solis, J. A1 - Krüger, Jörg A1 - Sturm, Heinz T1 - Femtosecond laser ablation of indium phosphide in air: dynamical, structural and morphological evolution N2 - The irradiation of single-crystalline indium phosphide (c-InP) by Ti:sapphire femtosecond laser pulses (130 fs, 800 nm) in air is studied by means of in-situ time resolved reflectivity measurements [fs-time-resolved microscopy (100 fs-10 ns) and point probing analysis (ns - µs)] and by complementary ex-situ surface analytical methods (Micro Raman Spectroscopy, Scanning Force, and Optical Microscopy). The dynamics of melting, ablation, and optical breakdown as well as structural changes resulting from rapid solidification are investigated in detail. Different laser-induced surface morphologies are characterized and discussed on the basis of recent ablation and optical breakdown models. KW - Femtosecond laser ablation KW - Optical breakdown KW - Time-resolved measurements KW - Semiconductor KW - Indium phosphide PY - 2010 SN - 1454-4164 VL - 12 IS - 3 SP - 421 EP - 426 PB - INOE & INFM CY - Bucharest AN - OPUS4-21082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voss, Heike A1 - Knigge, Xenia A1 - Knapic, D. A1 - Weise, Matthias A1 - Sahre, Mario A1 - Hertwig, Andreas A1 - Sacco, A. A1 - Rossi, A. M. A1 - Radnik, Jörg A1 - Müller, Kai A1 - Wasmuth, Karsten A1 - Krüger, Jörg A1 - Hassel, A. W. A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Picosecond laser processing of hierarchical micro–nanostructures on titanium alloy upon pre- and postanodization: morphological, structural, and chemical effects N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser processing step) plays an important role for the response of bone-forming osteoblasts—an effect that can be utilized for improving permanent dental or removable bone implants. For exploring these different surface functionalities, multimethod morphological, structural, and chemical characterizations are performed in combination with electrochemical pre- and postanodization for two different characteristic microspikes covered by nanometric laser-induced periodic surface structures on Ti–6Al–4V upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ≈1 ps pulse duration, 67 and 80 kHz pulse repetition frequency) at two distinct sets of laser fluence and beam scanning parameters. This work involves morphological and topographical investigations by scanning electron microscopy and white light interference microscopy, structural material examinations via X-ray diffraction, and micro-Raman spectroscopy, as well as near-surface chemical analyses by X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy. The results allow to qualify the mean laser ablation depth, assess the spike geometry and surface roughness parameters, and provide new detailed insights into the near-surface oxidation that may affect the different cell growth behavior for pre- or postanodized medical implants. T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics" CY - Strasbourg, France DA - 29.05.2023 KW - Hierarchical micro-nanostructures KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Ti-6Al-4V alloy KW - X-ray photoelectron spectroscopy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601962 DO - https://doi.org/10.1002/pssa.202300920 SN - 1862-6319 SP - 1 EP - 11 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-60196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Baudach, Steffen A1 - Kautek, Wolfgang A1 - Geuss, Markus A1 - Sturm, Heinz T1 - The precision of the femtosecond-pulse laser ablation of TiN films on silicon N2 - Ti:sapphire laser pulses of 130 fs and 800 nm were focused on 3.2-7m-thick TiN films by a 60-mm focal length lens in air. The morphology of the ablated areas generated by laser pulses at a fluence slightly above the ablation threshold was characterized in dependence on the pulse number by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The cavity profiles, depths, diameters, and volumes were quantitatively evaluated by AFM. The polarization state of the laser light is discussed as a further parameter, in addition to fluence and pulse number, that influences and controls the ablation precision of these materials. It was observed that circularly polarized radiation enhances the average ablation rates and reduces the roughness in the cavities by a factor of 2-3 as compared to linearly polarized radiation of the same incident laser fluence. Special attention was paid to the interfacial region between the coating and substrate. Ultrashort-pulse laser drilling into the Si substrate revealed the generation of columnar features which even may surmount the original coating under laser conditions. T2 - 5th International Conference on Laser Ablation ; COLA '99 CY - Göttingen, Germany DA - 1999-07-19 KW - Laser ablation KW - Picosecond PY - 1999 DO - https://doi.org/10.1007/s003390051425 SN - 0947-8396 VL - 69 IS - 7 SP - S399 EP - S402 PB - Springer CY - Berlin AN - OPUS4-778 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kirner, Sabrina A1 - Wirth, Thomas A1 - Sturm, Heinz A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Nanometer-resolved chemical analyses of femtosecond laser-induced periodic surface structures on titanium N2 - The chemical characteristics of two different types of laser-induced periodic surface structures (LIPSS), so-called high and low spatial frequency LIPSS (HSFL and LSFL), formed upon irradiation of titanium surfaces by multiple femtosecond laser pulses in air (30 fs, 790 nm, 1 kHz), are analyzed by various optical and electron beam based surface analytical techniques, including micro-Raman spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The latter method was employed in a high-resolution mode being capable of spatially resolving even the smallest HSFL structures featuring spatial periods below 100 nm. In combination with an ion sputtering technique, depths-resolved chemical information of superficial oxidation processes was obtained, revealing characteristic differences between the two different types of LIPSS. Our results indicate that a few tens of nanometer shallow HSFL are formed on top of a ∼150 nm thick graded superficial oxide layer without sharp interfaces, consisting of amorphous TiO2 and partially crystallized Ti2O3. The larger LSFL structures with periods close to the irradiation wavelength originate from the laser-interaction with metallic titanium. They are covered by a ∼200 nm thick amorphous oxide layer, which consists mainly of TiO2 (at the surface) and other titanium oxide species of lower oxidation states underneath. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Oxidation KW - Titanium KW - Auger electron spectroscopy PY - 2017 DO - https://doi.org/10.1063/1.4993128 SN - 0021-8979 VL - 122 IS - 10 SP - 104901, 1 EP - 9 PB - AIP Publishing CY - Melville, NY, USA AN - OPUS4-41905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -