TY - CONF A1 - Bonse, Jörn A1 - Hermens, U. A1 - Kirner, Sabrina V. A1 - Emonts, C. A1 - Comanns, P. A1 - Skoulas, E. A1 - Mimidis, A. A1 - Mescheder, H. A1 - Winands, K. A1 - Krüger, Jörg A1 - Stratakis, E. T1 - Mimicking lizard-like surface structures and their fluid transport upon ultrashort laser pulse irradiation of steel N2 - The wetting behavior of material surfaces can be controlled by surface structures. We functionalized case-hardened alloyed carbon steel to modify the wetting behavior using ultrashort laser pulses (fs- to ps-range). The laser processing was performed by scanning the laser beam across the surface of initially polished flat sample material. An experimental study of the laser processing parameters (peak fluence, scan velocity, line overlap) rendered an assignment of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, grooves, micro cones, etc.) possible. Analyzing the surface using optical as well as scanning electron microscopy allowed the identification of morphologies providing the optimum similarity to the natural skin of non-moisture havesting lizards. For mimicking skin structures of moisture-harvesting lizards, 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 revealed 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 and directional fluid transport properties. The results suggest possible applications of the laser-structured surfaces. T2 - European Materials Research Society (EMRS) Spring Meeting 2017, Symposium K “Bioinspired and biointegrated materials as new frontiers nanomaterials VII” CY - Strasbourg, France DA - 22.05.2017 KW - Lizards KW - Laser processing KW - Steel KW - Fluid transport KW - Wetting PY - 2017 AN - OPUS4-40421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Pentzien, Simone A1 - Krüger, Jörg T1 - X-ray emission during processing of metals with ultrashort laser pulses N2 - Ultrashort laser pulse micromachining features a high precision. By increasing the repetition rate of the applied laser to several 100 kHz, laser processing becomes quick and cost-effective and make this method attractive for industrial applications. Upon exceeding a critical laser intensity, hard X-ray radiation is generated as a side effect. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose becomes significant for high-repetition-rate laser systems so that radiation safety must be considered. T2 - 8th International LIPSS Workshop CY - Bochum, Germany DA - 27.09.2018 KW - X-ray KW - Laser processing KW - Ultrashort KW - Metals PY - 2018 AN - OPUS4-46104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bonse, Jörn A1 - Baudach, Steffen A1 - Krüger, Jörg A1 - Kautek, Wolfgang ED - Phipps, C. T1 - Femtosecond laser micromachining of technical materials N2 - Micromachining experiments were performed with Ti:sapphire laser pulses (130 fs - 150 fs, 800 nm, approximately 10 Hz) in air. Employing the direct focusing technique, highly absorbing titanium nitride (TiN) and weakly absorbing polyimide (PI) and polymethylmethacrylate (PMMA) served as target materials. The lateral and vertical precision of the laser ablation and morphological features were characterized by scanning force (SFM), scanning electron (SEM) and optical microscopy. For TiN, incubation can be observed, i.e. the single-pulse surface damage threshold (0.26 J/cm2) is by a factor of two greater than the threshold for 100 pulses. Ablation rates below 10 nm per pulse can be achieved. The evolution of sub-wavelength ripples is presented in dependence on pulse number and laser fluence, respectively. The incubation behavior of the polymers can be described by an accumulation model as for TiN. Experiments on PI with varying focal lengths result in the same modification thresholds. Different polarization states of light (linear, circular) lead to a variation of the ablation rate and to various morphological patterns in the ablation craters (wavelength ripples, cones). Swelling of PMMA occurred at fluences below the ablation threshold. T2 - 3rd SPIE's International Conference on High-Power Laser Ablation CY - Santa Fe, NM, USA DA - 24.04.2000 KW - Ablation KW - Femtosecond pulse laser KW - Laser processing KW - Micromachining KW - Polymer KW - Titanium nitride KW - Ripples PY - 2000 SN - 0-8194-3700-X U6 - https://doi.org/10.1117/12.407346 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 4065 SP - 161 EP - 172 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-967 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 U6 - 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 - Krüger, Jörg T1 - Structuring of thin films by ultrashort laser pulses N2 - Modern life and global communication would not be possible without technologically tailored thin films; they are omnipresent in daily life applications. In most cases, the films are deposited entirely at the carrying substrates in a specific processing step of the device or sample. In some cases, however, removal or modification must be performed locally, i.e., site-controlled and material selective through an additional laser processing step. For that ultrashort laser pulses with durations in the femtosecond and picosecond range can provide unique advantages and capabilities in industrially scalable schemes. This article reviews the current state of the research and corresponding industrial transfer related to the structuring of thin films by ultrashort pulsed lasers. It focuses on the pertinent historic developments, reveals the relevant physical and chemical effects, explores the ultimate limits, and discusses selected industrial and scientific applications. KW - Thin films KW - Laser processing KW - Ultrashort lasers KW - Laser damage KW - Femtosecond laser ablation PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-565732 SN - 0947-8396 SN - 1432-0630 VL - 129 IS - 1 SP - 1 EP - 38 PB - Springer CY - Berlin AN - OPUS4-56573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Lasagni, A. F. T1 - Editorial: Laser micro- and nano-material processing – Part 1 N2 - This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods. KW - Laser processing KW - Microstructures KW - Nanostructures KW - Applications PY - 2020 U6 - https://doi.org/10.1515/aot-2020-0009 SN - 2193-8576 SN - 2193-8584 VL - 9 IS - 1-2 SP - 7 EP - 9 PB - De Gruyter CY - Berlin AN - OPUS4-50797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Mann, Guido A1 - Krüger, Jörg A1 - Marcinkowski, M. A1 - Eberstein, M. T1 - Femtosecond laser-induced removal of silicon nitride layers from doped and textured silicon wafers used in photovoltaics N2 - The removal of a 75- to 90-nm-thick passivating silicon nitride antireflection coating from standard textured multicrystalline silicon photovoltaic wafers with a typical diffused 90-Ω/sq-emitter upon irradiation with near-infrared femtosecond laser pulses (790 nm central wavelength, 30 fs pulse duration) is studied experimentally. The laser irradiation areas are subsequently characterized by complementary optical microscopy, scanning electron microscopy and depth profiling chemical analyses using secondary ion mass spectrometry. The results clarify the thin-film femtosecond laser ablation scenario and outline the process windows for selective antireflection coating removal. KW - Photovoltaics KW - Solar cell KW - Laser processing KW - FS-laser ablation KW - Silicon nitride PY - 2013 U6 - https://doi.org/10.1016/j.tsf.2013.07.005 SN - 0040-6090 VL - 542 SP - 420 EP - 425 PB - Elsevier CY - Amsterdam AN - OPUS4-28874 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 U6 - 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 - CONF A1 - Eberstein, M. A1 - Geier, M. A1 - Grießmann, H. A1 - Partsch, U. A1 - Voelkel, L. A1 - Böhme, R. A1 - Pentzien, Simone A1 - Koter, Robert A1 - Mann, Guido A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Towards an industrial laser doping process for the selective emitter using phosphoric acid as dopant N2 - Different laser supported approaches have already been realized, proving the great potential of laserdoped selective emitters (LDSE). However, it is challenging to establish a low-cost process by using pulsed laser tools. So far a single-step process only leads to satisfying results utilizing cw-lasers. In this paper we have examined a two-step process to produce laser-doped selective emitters on multicrystalline textured standard silicon photovoltaic wafers (90-Ω/sq-Emitter, SiN-antireflection coating (ARC)). The precise ARC removal by near-infrared fs-laser pulses (30 fs, 800 nm), and the doping of uncoated silicon wafers by ns-laser pulses (8 ns, 532 nm) were systematically investigated. In the fs-experiment, optimum conditions for ARC removal were identified. In the nsexperiments under suitable conditions (melting regime), the phosphorous concentration underneath the wafer surface was significantly increased and the sheet resistance was reduced by nearly a factor of two. Moreover, electrical measurements on fired metallization fingers deposited on the laser processed wafers showed low contact resistances. Hence, wafer conditioning with combined fs-laser- and ns-laser-processes are expected to be a promising technology for producing selective emitters. T2 - 26th European photovoltaic solar energy conference and exhibition CY - Hamburg, Germany DA - 05.09.2011 KW - Laser processing KW - Doping KW - Selective emitter KW - Multicrystalline silicon PY - 2011 SN - 3-936338-27-2 U6 - https://doi.org/10.4229/26thEUPVSEC2011-2BV.1.2 SP - 1220 EP - 1223 AN - OPUS4-24996 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 U6 - 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 -