TY - GEN A1 - Gruber, D. A1 - Husinsky, W. A1 - Grabner, G. A1 - Baumgartner, I. A1 - Scholman, J. A1 - Krüger, Jörg A1 - Kautek, Wolfgang ED - Waidelich, W. T1 - Nano- and Femtosecond-Laser Processing of Human Donor Corneal-Transplants and Lenticules for Corneal Surgery T2 - Laser in Forschung und Technik = Laser in research and engineering T2 - 12. Internationaler Kongress Laser 95 CY - Munich, Germany DA - 1995-06-01 PY - 1996 SN - 3-540-61316-1 SP - 397 EP - 400 PB - Springer CY - Berlin AN - OPUS4-11895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kautek, Wolfgang A1 - Rudolph, Pascale A1 - Krüger, Jörg A1 - Rosenfeld, A. A1 - Lorenz, M. A1 - Ashkenasi, D. T1 - Morphological and mechanical investigations of bariumalumoborosilicate glass surfaces processed with 700-fs laser pulses JF - Applied physics A N2 - We present surface micro-modifications of bariumalumoborosilicate glasses with a high transformation temperature near 700 °C. Laser processing of the glass substrate was realized by using ultra-short laser pulses at 800 nm. The morphological conversion of the laser-treated surfaces was characterized by scanning force microscopy and nano-indentation. A hardness increase by at least a factor of six on the laser ablation crater edge relative to illuminated non- ablated areas shows that the material in the crater walls underwent drastic morphological and mechanical changes. In this heat- and shock-affected zone, the material became more elastic as a result of increased stress. T2 - 5th International Conference on Laser Ablation ; COLA '99 CY - Göttingen, Germany DA - 1999-07-19 KW - Bariumalumoborosilicate glass surfaces PY - 1999 DO - https://doi.org/10.1007/s003390051523 SN - 0947-8396 VL - 69 IS - 7 SP - S759 EP - S761 PB - Springer CY - Berlin AN - OPUS4-775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Krüger, Jörg A1 - Wurster, R. ED - M. Castillejo, ED - P. Moreno, ED - M. Oujja, ED - R. Radvan, ED - J. Ruiz, T1 - Monitoring of the laser cleaning process of artificially soiled paper T2 - LACONA VII International Conference, "Lasers in the Conservation of Artworks", September 17-21, 2007, Madrid, Spain (Proceedings) N2 - Laser cleaning of soiled paper is a challenging task due to the fact that a contamination has to be removed and a fragile organic material has to be preserved. The ejection of particles forms a significant channel for the removal of unwanted surface contaminations and can be exploited for an in-situ monitoring of the cleaning procedure. 532-nm-nanosecond single and multi pulse laser cleaning of artificially soiled Whatman© paper was performed. Particles were registered with a dust monitor. These in-situ experiments were combined with ex-situ investigations of cleaning and substrate damage thresholds by means of light and scanning electron microscopic techniques. The cleaning efficiency measured by a multi-spectral imaging system was compared to the in-situ particle monitoring. Additionally, possible color changes of the paper substrate were evaluated. T2 - LACONA VII International Conference, "Lasers in the Conservation of Artworks" CY - Madrid, Spain DA - 2007-09-17 PY - 2008 SN - 978-0-415-47596-9 SP - 345 EP - 351 PB - Taylor & Francis AN - OPUS4-17974 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Modifikation und Zerstörung von optischen Komponenten als Limit für die Anwendung ultrakurzer Laserimpulse T2 - Institutskolloquium Leibniz-Institut für Oberflächenmodifizierung T2 - Institutskolloquium Leibniz-Institut für Oberflächenmodifizierung CY - Leipzig, Germany DA - 2009-05-07 PY - 2009 AN - OPUS4-19112 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Lenzner, Matthias T1 - Modification and Ablation of Semiconductors by Femtosecond Laser Pulses JF - Recent research developments in applied physics N2 - Physical and chemical phenomena resulting from irradiation of silicon and indium phosphide with ultrashort laser pulses (~100fs) were investigated with respect to the difference between single- and multiple-pulse treatment. In the single-pulse case, several processes were identified: modification, recrystallization and ablation. All processes exhibit a distinct treshold behaviour. A two photon-absorption coefficient can be determined from a single spatial ablation profile. Accumulation effects were observed for multi-pulse illumination. Different morphological features like bubbles, rippels and microcolumns were found. PY - 2002 VL - 5 IS - 2 SP - 437 EP - 461 PB - Transworld Research Network CY - Trivandrum AN - OPUS4-1585 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 JF - Applied Physics A 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 - 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 JF - Applied Surface Science 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 - 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 JF - Applied Physics A 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 - GEN A1 - Rudolph, Pascale A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Mikrostrukturierung von Glas zur Erzeugung kristalliner Si-Schichten T2 - Laser in der Materialbearbeitung PY - 2000 IS - 12 SP - 7 EP - 36 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-985 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Mikromaterialbearbeitung mit ultrakurzen Laserimpulsen: Vorzüge, Probleme, Sicherheitsaspekte T2 - Seminar "Laser in der Feinbearbeitung" T2 - Seminar "Laser in der Feinbearbeitung" CY - Teltow, Germany DA - 2005-10-22 PY - 2005 AN - OPUS4-10950 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Mikrobearbeitung mit ultrakurzen Laserimpulsen T2 - Seminar Laser-Materialbearbeitung für die industrielle Fertigung (Photon Laser Engineering) T2 - Seminar Laser-Materialbearbeitung für die industrielle Fertigung (Photon Laser Engineering) CY - Berlin, Germany DA - 2010-03-23 PY - 2010 AN - OPUS4-22574 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Symietz, Christian A1 - Lehmann, Erhard A1 - Gildenhaar, Renate A1 - Hackbarth, Andreas A1 - Berger, Georg A1 - Krüger, Jörg T1 - Mechanical stability of Ti6Al4V implant material after femtosecond laser irradiation JF - Journal of applied physics N2 - The surface of a titanium alloy (Ti6Al4V) implant material was covered with a bioactive calcium alkali phosphate ceramic with the aim to accelerate the healing and to form a stronger bond to living bone tissue. To fix the ceramic powder we used a femtosecond laser, which causes a thin surface melting of the metal. It is a requirement to prove that the laser irradiation would not reduce the lifetime of implants. Here we present the results of mechanical stability tests, determined by the rotating bending fatigue strength of sample rods. After describing the sample surfaces and their modifications caused by the laser treatment we give evidence for an unchanged mechanical stability. This applies not only to the ceramic fixation but also to a comparatively strong laser ablation. KW - Aluminium alloys KW - Bending strength KW - Bioceramics KW - Bone KW - Calcium compounds KW - Fatigue KW - Fatigue testing KW - High-speed optical techniques KW - Laser ablation KW - Melting KW - Orthopaedics KW - Prosthetics KW - Rods (structures) KW - Surface treatment KW - Titanium alloys KW - Vanadium alloys PY - 2012 DO - https://doi.org/10.1063/1.4737576 SN - 0021-8979 SN - 1089-7550 VL - 112 IS - 2 SP - 023103-1 - 023103-5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmid, M. A1 - Heidmann, B. A1 - Ringleb, F. A1 - Eylers, K. A1 - Ernst, O. A1 - Andree, Stefan A1 - Bonse, Jörn A1 - Boeck, T. A1 - Krüger, Jörg T1 - Locally grown Cu(In,Ga)Se2 micro islands for concentrator solar cells T2 - Proceedings of SPIE 10527, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VII N2 - Light concentration opens up the path to enhanced material efficiency of solar cells via increased conversion efficiency and decreased material requirement. For true material saving, a fabrication method allowing local growth of high quality absorber material is essential. We present two scalable fs-laser based approaches for bottom-up growth of Cu(In,Ga)Se2 micro islands utilizing either site-controlled assembly of In(,Ga) droplets on laser-patterned substrates during physical vapor deposition, or laser-induced forward transfer of (Cu,In,Ga) layers for local precursor arrangement. The Cu(In,Ga)Se2 absorbers formed after selenization can deliver working solar devices showing efficiency enhancement under light concentration. T2 - SPIE OPTO, 2018 CY - San Francisco, USA DA - 29.01.2018 KW - Chalcopyrite KW - Cu(In,Ga)Se2 KW - Fs-laser patterning KW - Laser-induced forward transfer KW - Micro solar cell PY - 2018 SN - 978-1-5106-1540-3 SN - 0277-786X SN - 1996-756X VL - 10527 SP - 1052707-1 EP - 1052707-9 PB - SPIE CY - Bellingham, WA, USA AN - OPUS4-44450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heidmann, B. A1 - Ringleb, F. A1 - Eylers, K. A1 - Levcenko, S. A1 - Bonse, Jörn A1 - Andree, Stefan A1 - Krüger, Jörg A1 - Unold, T. A1 - Boeck, T. A1 - Lux-Steiner, M. C. A1 - Schmid, M. T1 - Local growth of CuInSe2 micro solar cells for concentrator application JF - Materials Today Energy N2 - A procedure to fabricate CuInSe2 (CISe) micro-absorbers and solar cells for concentrator applications is presented. The micro-absorbers are developed from indium precursor islands, which are deposited on a molybdenum coated glass substrate (back contact), followed by deposition of copper on top and subsequent selenization as well as selective etching of copper selenides. In order to compare the properties of the locally grown absorbers to those of conventional large area CISe films, we systematically examine the compositional and morphological homogeneity of the micro absorbers and carry out photoluminescence measurements. Preliminary devices for micro-concentrator solar cell applications are fabricated by optimizing the copper to indium ratio and the size of the indium precursor islands. The resulting micro solar cells provide a characteristic I–V curve under standard illumination conditions (1 sun). KW - Micro solar cells KW - Light concentration KW - CuInSe2 KW - Absorber optimization KW - Chalcopyrite PY - 2017 UR - https://www.sciencedirect.com/science/article/pii/S2468606917300953 DO - https://doi.org/10.1016/j.mtener.2017.10.010 SN - 2468-6069 VL - 6 IS - December 2017 SP - 238 EP - 247 PB - Elsevier Ltd. AN - OPUS4-42801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudolph, Pascale A1 - Pentzien, Simone A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - König, E. T1 - Laserreinigung von Pergament und Papier JF - Restauro PY - 1998 SN - 0933-4017 IS - 6 SP - 396 EP - 402 PB - Callwey CY - München AN - OPUS4-11598 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Lußky, K. A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Engel, P. T1 - Laserreinigung von künstlich verschmutzten europäischen Papieren des 19. Jahrhunderts T2 - Tagung Laseranwendung in Restaurierung und Denkmalpflege T2 - Tagung Laseranwendung in Restaurierung und Denkmalpflege CY - Osnabrück, Germany DA - 2009-01-29 PY - 2009 AN - OPUS4-18228 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Jörg A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Lußky, Katharina A1 - Engel, P. ED - Günter Wiedemann, ED - Udo Klotzbach, ED - Ulrich Bauer-Bornemann, T1 - Laserreinigung von künstlich verschmutzten europäischen Papieren des 19. Jahrhunderts T2 - Laseranwendung in Restaurierung und Denkmalpflege - Grundlagen - Chancen - Perspektiven N2 - Diese Arbeit beschreibt die Laserreinigung von gebräuchlichen Papieren des 19. Jahrhunderts in Kombination mit zwei Schmutzvarianten. Aufgrund der weiten Verbreitung in Bibliotheken und Kunstsammlungen wurden Hadernpapier und holzhaltiges Papier ausgewählt. Als Referenz diente Whatman-Filterpapier. Zur künstlichen Verschmutzung wurden Zeichenkohle oder Standardschmutz (Standard Test Dust SAE J 726 fine, mit Flammruß im Verhältnis 20:1 gemischt) mit Hilfe von Pinsel und Staubsauger jeweils auf die drei Papierarten aufgetragen und in den Faserverbund eingesaugt. Die Nutzung von Modellproben erweist sich für grundlegende Untersuchungen als vorteilhaft, da das Vorhandensein hinreichend großer Flächen (gleichartiger Objekte) für einen Vergleich mit Ergebnissen klassischer Reinigungstechniken unabdingbar ist. Die preiswerten Proben erlauben darüber hinaus auch die Anwendung zerstörender Analysetechniken. Für die Laserreinigungsexperimente wurde ein Nd:YAG-Laser mit Impulsdauern in der Größenordnung von 10 ns bei 532 nm Wellenlänge und einer Repetitionsrate von 500 Hz verwendet. Die Laser-Bearbeitungsstation erlaubt die flächige Bearbeitung von Objekten, wobei der Laserstrahl bewegt wird. Der Laser wird mittels Computer ferngesteuert und unter Klasse-1-Sicherheitsbedingungen betrieben. Bei der Untersuchung der Modellproben wurde jeweils die Anzahl der Impulse pro Probenstelle sowie die Laser-Energiedichte variiert. Ziel der Arbeiten war die Ermittlung eines Laser-Arbeitsbereiches für die Reinigung der verschiedenen Papierproben. Die Modellobjekte wurden vor und nach der Laserbehandlung mittels lichtmikroskopischer, rasterelektronenmikroskopischer und colorimetrischer Analysemethoden untersucht. T2 - Tagung "Laseranwendung in Restaurierung und Denkmalpflege" CY - Osnabrück, Deutschland DA - 2009-01-30 KW - Laserreinigung KW - Nd:YAG-Laser KW - Hadernpapier KW - Holzhaltiges Papier KW - Filterpapier KW - Mikroskopie KW - Farbmessung PY - 2009 SN - 978-3-8167-8106-6 SP - 177 EP - 189 PB - Fraunhofer IRB Verl. CY - Stuttgart AN - OPUS4-20059 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Laserreinigung von Kunst- und Kulturgut am Beispiel organischer Materialien T2 - Innovationsforum Inn-O-Kultur T2 - Innovationsforum Inn-O-Kultur CY - Erfurt, Germany DA - 2014-07-14 PY - 2014 AN - OPUS4-31113 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Lasereinsatz zur Dekontamination von Biozid-belasteten Kulturgütern N2 - Um Kulturgüter aus organischen Substanzen zu bewahren, wurden besonders in den 70er und 80er Jahren Biozide, wie z.B. das flüssige Holzschutzmittel Hylotox-59, eingesetzt. Es enthält Dichlordiphenyltrichlorethan (DDT), das im Verdacht steht, krebsauslösend zu sein. Durch „Ausblühen“ der Chlorverbindungen entstehen an der Holzoberfläche Kristallstrukturen. Eine Entfernung dieser Kristalle und damit eine Abreicherung von Chlor an der Oberfläche sind sehr erwünscht. Eine Laserreinigung von ausgewählten Teilen musealer Holzobjekte aus dem Schlossmuseum Sondershausen wurde mit Impulsdauern im Femto- und Nanosekundenbereich durchgeführt. Der Chlornachweis vor und nach dem Lasereinsatz wurde mittels Röntgenfluoreszenzanalytik (RFA) erbracht. Chlorabreicherungen von 55-70% und 75% wurden beim Einsatz von ns-Impulsen bei 1064 nm Wellenlänge bzw. fs-Impulsen bei 800 nm Wellenlänge erreicht. Im fs-Fall verblieben keine kristallinen DDT-Rückstände auf den Probenoberflächen. T2 - 12. Thementage Grenz- und Oberflächentechnik (ThGOT) CY - Zeulenroda, Germany DA - 14.03.2017 KW - Laserreinigung KW - Femtosekundenlaser KW - Nanosekundenlaser KW - Holz KW - DDT PY - 2017 AN - OPUS4-39597 LA - deu 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? JF - Laser & Photonics Reviews 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 - CONF A1 - Krüger, Jörg T1 - Laser-Reinigung von Papier, Pergament und Gewebe - Eine Einführung T2 - Fachtagung, Hochschule für Angewandte Wissenschaft und Kunst (HAWK) T2 - Fachtagung, Hochschule für Angewandte Wissenschaft und Kunst (HAWK) CY - Hildesheim, Germany DA - 2007-10-01 PY - 2007 AN - OPUS4-15722 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Laser-Reinigung von Papier, Pergament und Gewebe T2 - OpTecBB-Fokusseminar "Cultural Heritage", PTB T2 - OpTecBB-Fokusseminar "Cultural Heritage", PTB CY - Berlin, Germany DA - 2007-05-03 PY - 2007 AN - OPUS4-14761 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Laser-induzierte Zerstörung von optischen Komponenten bei Anwendung von Femtosekunden-Impulsen T2 - Workshop Lasermikrobearbeitung T2 - Workshop Lasermikrobearbeitung CY - Berlin, Germany DA - 2008-03-11 PY - 2008 AN - OPUS4-16676 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Höhm, S. A1 - Kirner, Sabrina V. A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Laser-induced periodic surface structures — a scientific evergreen JF - IEEE Journal of Selected Topics in Quantum Electronics N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon and can be generated on almost any material upon irradiation with linearly polarized radiation. With the availability of ultrashort laser pulses, LIPSS have gained an increasing attraction during the past decade, since these structures can be generated in a simple single-step process, which allows a surface nanostructuring for tailoring optical, mechanical, and chemical surface properties. In this study, the current state in the field of LIPSS is reviewed. Their formation mechanisms are analyzed in ultrafast time-resolved scattering, diffraction, and polarization constrained double-pulse experiments. These experiments allow us to address the question whether the LIPSS are seeded via ultrafast energy deposition mechanisms acting during the absorption of optical radiation or via self-organization after the irradiation process. Relevant control parameters of LIPSS are identified, and technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. KW - Laser ablation KW - Nanostructures KW - Surface functionalization KW - Surface texture KW - Laser-induced periodic surface structures (LIPSS) PY - 2017 DO - https://doi.org/10.1109/JSTQE.2016.2614183 SN - 1077-260X SN - 1558-4542 VL - 23 IS - 3 SP - 9000615 PB - IEEE AN - OPUS4-38633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures on zinc oxide crystals upon two-colour femtosecond double-pulse irradiation JF - Physica Scripta N2 - In order to study the temporally distributed energy deposition in the formation of laser-induced periodic surface structures (LIPSS) on single-crystalline zinc oxide (ZnO), two-colour double-fs-pulse experiments were performed. Parallel or cross-polarised double-pulse sequences at 400 and 800 nm wavelength were generated by a Mach–Zehnder interferometer, exhibiting inter-pulse delays up to a few picoseconds between the sub-ablation 50-fs-pulses. Twenty two-colour double-pulse sequences were collinearly focused by a spherical mirror to the sample surface. The resulting LIPSS periods and areas were analysed by scanning electron microscopy. The delay-dependence of these LIPSS characteristics shows a dissimilar behaviour when compared to the semiconductor silicon, the dielectric fused silica, or the metal titanium. A wavelength-dependent plasmonic mechanism is proposed to explain the delay-dependence of the LIPSS on ZnO when considering multi-photon excitation processes. Our results support the involvement of nonlinear processes for temporally overlapping pulses. These experiments extend previous two-colour studies on the indirect semiconductor silicon towards the direct wide band-gap semiconductor ZnO and further manifest the relevance of the ultrafast energy deposition for LIPSS formation. KW - Laser-induced periodic surface structures, LIPSS KW - Laser ablation KW - Surface plasmon polariton PY - 2017 DO - https://doi.org/10.1088/1402-4896/aa5578 SN - 1402-4896 SN - 0031-8949 VL - 92 IS - 3 SP - Article 034003, 1 EP - 7 PB - IOP CY - Bristol, UK AN - OPUS4-39082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures on titanium upon single- and two-color femtosecond double-pulse irradiation JF - Optics express N2 - Single- and two-color double-fs-pulse experiments were performed on titanium to study the dynamics of the formation of laser-induced periodic surface structures (LIPSS). A Mach-Zehnder inter-ferometer generated polarization controlled (parallel or cross-polarized) double-pulse sequences in two configurations – either at 800 nm only, or at 400 and 800 nm wavelengths. The inter-pulse delays of the individual 50-fs pulses ranged up to some tens of picoseconds. Multiple of these single- or two-color double-fs-pulse sequences were collinearly focused by a spherical mirror to the sample surface. In both experimental configurations, the peak fluence of each individual pulse was kept below its respective ablation threshold and only the joint action of both pulses lead to the formation of LIPSS. Their resulting characteristics were analyzed by scanning electron microscopy and the periods were quantified by Fourier analyses. The LIPSS periods along with the orientation allow a clear identification of the pulse which dominates the energy coupling to the material. A plasmonic model successfully explains the delay-dependence of the LIPSS on titanium and confirms the importance of the ultrafast energy deposition stage for LIPSS formation. PY - 2015 DO - https://doi.org/10.1364/OE.23.025959 SN - 1094-4087 VL - 23 IS - 20 SP - 25959 EP - 25971 PB - Optical Society of America CY - Washington, DC AN - OPUS4-34354 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 - Laser-induced periodic surface structures on fused silica upon cross-polarized two-color double-fs-pulse irradiation JF - Applied surface science N2 - The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration) is studied by cross-polarized two-color double-fs-pulse experiments. In order to analyze the relevance of temporally distributed energy deposition in the early stage of LIPSS formation, a Mach-Zehnder interferometer was used for generating multiple double-pulse sequences at two different wavelengths (400 and 800 nm). The inter-pulse delay between the individual cross-polarized pulses of each sequence was systematically varied in the sub-ps range and the resulting LIPSS morphologies were characterized by scanning electron microscopy. It is found that the polarization of the first laser pulse arriving to the surface determines the orientation and the periodicity of the LIPSS. These two-color experiments further confirm the importance of the ultrafast energy deposition to the silica surface for LIPSS formation, particularly by the first laser pulse of each sequence. The second laser pulse subsequently reinforces the previously seeded spatial LIPSS characteristics (period, orientation). KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Double-pulse experiments KW - Ultrafast optical techniques KW - Mach-Zehnder interferometer PY - 2015 DO - https://doi.org/10.1016/j.apsusc.2014.09.101 SN - 0169-4332 SN - 1873-5584 VL - 336 SP - 39 EP - 42 PB - North-Holland CY - Amsterdam AN - OPUS4-32860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Höhm, S. A1 - Herzlieb, M. A1 - Rosenfeld, A. A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures (LIPSS) upon femtosecond two-color double-pulse irradiation T2 - European Materials Research Society (EMRS) Spring Meeting 2015, Symposium CC "Laser and plasma processing for advanced applications in material science" T2 - European Materials Research Society (EMRS) Spring Meeting 2015, Symposium CC "Laser and plasma processing for advanced applications in material science" CY - Lille, France DA - 2015-05-11 PY - 2015 AN - OPUS4-32767 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Höhm, S. A1 - Kirner, Sabrina A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Laser-induced periodic surface structures (LIPSS) - A scientific evergreen T2 - OSA Technical Digest (2016) N2 - The current state in the field of laser-induced periodic surface structures (LIPSS, ripples) is reviewed. Their formation mechanisms are analyzed in ultrafast experiments (time-resolved diffraction and polarization controlled double-pulse experiments) and technological applications are demonstrated. T2 - Conference on Lasers and Electro-Optics (CLEO) - Science and Innovations 2016 CY - San Jose, CA, USA DA - 05.06.2016 KW - Laser materials processing KW - Optics at surfaces KW - Ultrafast phenomena KW - Laser-induced periodic surface strcutures (LIPSS) KW - Femtosecond laser ablation PY - 2016 SN - 978-1-943580-11-8 DO - https://doi.org/10.1364/CLEO_SI.2016.STh1Q.3 SP - STh1Q.3, 1 EP - 2 PB - Optical Society of America AN - OPUS4-37072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Krüger, Jörg ED - Sugioka, K. T1 - Laser-Induced Periodic Surface Structures (LIPSS) T2 - Handbook of Laser Micro- and Nano-Engineering N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon and can be generated on almost any material by irradiation with linearly polarized radiation. This chapter reviews the current state in the field of LIPSS, which are formed in a “self-ordered” way and are often accompanying materials processing applications. LIPSS can be produced in a single-stage process and enable surface nanostructuring and, in turn, adaption of optical, mechanical, and chemical surface properties. Typically, they feature a structural size ranging from several micrometers down to less than 100 nm and show a clear correlation with the polarization direction of the light used for their generation. Various types of LIPSS are classified, relevant control parameters are identified, and their material-specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Laser ablation KW - Microstructures KW - Nanostrcutures PY - 2021 SN - 978-3-030-63646-3 (Print) SN - 978-3-030-63647-0 (Online) DO - https://doi.org/10.1007/978-3-030-63647-0_17 SP - 879 EP - 936 PB - Springer-Nature Switzerland AG CY - Cham ET - 1 AN - OPUS4-53728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Krüger, Jörg ED - Sugioka, K. T1 - Laser-induced periodic surface structures (LIPSS) T2 - Handbook of laser micro- and nano-engineering N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon and can be generated on almost any material by irradiation with linearly polarized radiation. This chapter reviews the current state in the field of LIPSS, which are formed in a “self-ordered” way and are often accompanying materials processing applications. LIPSS can be produced in a single-stage process and enable surface nanostructuring and, in turn, adaption of optical, mechanical, and chemical surface properties. Typically, they feature a structural size ranging from several micrometers down to less than 100 nm and show a clear correlation with the polarization direction of the light used for their generation. Various types of LIPSS are classified, relevant control parameters are identified, and their material-specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. KW - Laser-induced periodic surface structures (LIPSS) KW - Laser ablation KW - Femtosecond laser KW - Nanostructures KW - Microstructures PY - 2020 SN - 978-3-319-69537-2 DO - https://doi.org/10.1007/978-3-319-69537-2_17-1 SP - 1 EP - 59 PB - Springer Nature CY - Cham, Switzerland ET - 1 AN - OPUS4-51332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Bonse, Jörn A1 - Kirner, Sabrina V. A1 - Krüger, Jörg ED - Sugioka, K. T1 - Laser-induced periodic surface structures (LIPSS) T2 - Handbook of laser micro- and nano-engineering N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon and can be generated on almost any material by irradiation with linearly polarized radiation. This chapter reviews the current state in the field of LIPSS, which are formed in a “self-ordered” way and are often accompanying materials processing applications. LIPSS can be produced in a single-stage process and enable surface nanostructuring and, in turn, adaption of optical, mechanical, and chemical surface properties. Typically, they feature a structural size ranging from several micrometers down to less than 100 nm and show a clear correlation with the polarization direction of the light used for their generation. Various types of LIPSS are classified, relevant control parameters are identified, and their material-specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. KW - Femtosecond laser KW - Laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Microstructures KW - Nanostructures PY - 2021 SN - 978-3-319-69537-2 DO - https://doi.org/10.1007/978-3-319-69537-2_17-2 SP - 1 EP - 59 PB - Springer Nature CY - Cham, Switzerland ET - 2 AN - OPUS4-51493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heitz, J. A1 - Plamadeala, C. A1 - Muck, M. A1 - Habidzadeh, H. A1 - Baumgartner, W. A1 - Weth, A. A1 - Steinwender, C. A1 - Blessberger, H. A1 - Kellermair, J. A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Guntner, A. S. A1 - Hassel, A. W. T1 - Laser-induced microstructures on Ti substrates for reduced cell adhesion JF - Journal für Kardiologie - Austrian Journal of Cardiology N2 - The abstract summarizes the poster presented at the "Kardiologie im Zentrum - Fortbildung der Klinik für Kardiologie und Intensivmedizin Kepler Universitätsklinikum Linz", held between October 20th and 31st in Linz, Austria. The poster has been awarded the 2nd place of the "Best Poster Award". T2 - Kardiologie im Zentrum - Fortbildung der Klinik für Kardiologie und Intensivmedizin Kepler Universitätsklinikum Linz CY - Linz, Austria DA - 20.10.2017 KW - Femtosecond laser processing KW - Titanium alloy KW - Cell adhesion KW - Pacemaker PY - 2017 UR - http://www.kup.at/kup/pdf/14098.pdf SN - 1024-0098 VL - 24 IS - 11-12 SP - 292 EP - 292 PB - Krause & Pachernegg GmbH CY - Gablitz, Austria AN - OPUS4-43160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Laser-induced damage threshold (LIDT) testing of oxide and metal coatings with sub-30 fs pulses T2 - Workshop on Laser-Induced Damage (LZH Hannover) T2 - Workshop on Laser-Induced Damage (LZH Hannover) CY - Hanover, Germany DA - 2007-07-04 PY - 2007 AN - OPUS4-14979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Lenzner, M. A1 - Sartania, S. A1 - Spielmann, Ch. A1 - Krausz, F. T1 - Laser micromachining of barium aluminium borosilicate glass with pulse durations between 20 fs and 3 ps JF - Applied surface science KW - Laser micromachining KW - Subpicosecond laser ablation KW - Barium aluminium borosilicate glass PY - 1998 SN - 0169-4332 SN - 1873-5584 IS - 127-129 SP - 892 EP - 898 PB - North-Holland CY - Amsterdam AN - OPUS4-887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kautek, Wolfgang A1 - Pentzien, Simone A1 - Rudolph, Pascale A1 - Krüger, Jörg A1 - König, E. T1 - Laser interaction with coated collagen und cellulose fibre composites: fundamentals of laser cleaning of ancient parchment manuscripts and paper JF - Applied surface science N2 - Laser cleaning of delicate biological composite materials such as ancient parchment manuscripts from the 15th and 16th century and printed paper from the 19th century is demonstrated with an ultraviolet excimer pulsed laser at 308 nm. Laser fluence levels must stay below the ablation and destruction threshold of the parchment or paper substrate, and have to surpass the threshold of the contaminant matter. Foreign layers to be removed must exhibit a higher optical density than the artifact substrates. Synthetic carbonaceous dirt modelled by water-soluble black crayons showed a characteristically weak featureless laser-induced plasma spectroscopy spectrum near the noise limit. It turned out that laser-induced plasma spectroscopy is of limited use in monitoring halting points (or etch-stops) because it relies on the destruction not only of the laterally inhomogenously distributed contaminant but also of pigment phases on a microscopically rough parchment substrate. Laser-induced fluorescence spectroscopy, however, promises to be a valuable non-destructive testing technique for etch-stop monitoring. KW - Laser KW - Parchment KW - Papery KW - Spectroscopy KW - Laser cleaning PY - 1998 SN - 0169-4332 SN - 1873-5584 VL - 127-129 SP - 746 EP - 754 PB - North-Holland CY - Amsterdam AN - OPUS4-11516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stratakis, E. A1 - Bonse, Jörn A1 - Heitz, J. A1 - Siegel, J. A1 - Tsibidis, G.D. A1 - Skoulas, E. A1 - Papadopoulos, A. A1 - Mimidis, A. A1 - Joel, A.-C. A1 - Comanns, P. A1 - Krüger, Jörg A1 - Florian, C. A1 - Fuentes-Edfuf, Y. A1 - Solis, J. A1 - Baumgartner, W. T1 - Laser engineering of biomimetic surfaces JF - Materials Science and Engineering: R: Reports N2 - The exciting properties of micro- and nano-patterned surfaces found in natural species hide a virtually endless potential of technological ideas, opening new opportunities for innovation and exploitation in materials science and engineering. Due to the diversity of biomimetic surface functionalities, inspirations from natural surfaces are interesting for a broad range of applications in engineering, including phenomena of adhesion, friction, wear, lubrication, wetting phenomena, self-cleaning, antifouling, antibacterial phenomena, thermoregulation and optics. Lasers are increasingly proving to be promising tools for the precise and controlled structuring of materials at micro- and nano-scales. When ultrashort-pulsed lasers are used, the optimal interplay between laser and material parameters enables structuring down to the nanometer scale. Besides this, a unique aspect of laser processing technology is the possibility for material modifications at multiple (hierarchical) length scales, leading to the complex biomimetic micro- and nano-scale patterns, while adding a new dimension to structure optimization. This article reviews the current state of the art of laser processing methodologies, which are being used for the fabrication of bioinspired artificial surfaces to realize extraordinary wetting, optical, mechanical, and biological-active properties for numerous applications. The innovative aspect of laser functionalized biomimetic surfaces for a wide variety of current and future applications is particularly demonstrated and discussed. The article concludes with illustrating the wealth of arising possibilities and the number of new laser micro/nano fabrication approaches for obtaining complex high-resolution features, which prescribe a future where control of structures and subsequent functionalities are beyond our current imagination. KW - Biomimetic surfaces KW - Laser processing KW - Surface functionalization KW - Bioinspiration KW - Bionic materials PY - 2020 DO - https://doi.org/10.1016/j.mser.2020.100562 SN - 0927-796X VL - 141 SP - 100562-1 EP - 100562-47 PB - Elsevier B.V. AN - OPUS4-50927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Holle, H. A1 - Kautek, W. A1 - Pentzien, Simone A1 - Krüger, Jörg A1 - Mäder, M. A1 - Schreiner, M. T1 - Laser cleaning on historic picture postcards T2 - Research in book and paper conservation in Europe - a state of the art N2 - This contribution compares traditional cleaning and laser methods. Partial laser cleaning with a nanosecond pulse laser (wavelength of 532 nm) has proved very promising for future application in paper conservation-restoration. Traditional cleaning methods are not always sufficient or successful in surface cleaning of objects of art. Comparative studies of traditional paper cleaning methods and laser cleaning were made on several historic picture postcards printed with the chromolithography technique. PY - 2009 SN - 978-3-85028-490-5 SP - 189 EP - 206 PB - Berger Horn CY - Wien, Austria AN - OPUS4-20397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lerber, K. von A1 - Strlic, M. A1 - Kolar, J. A1 - Krüger, Jörg A1 - Pentzien, Simone A1 - Kennedy, C. A1 - Wess, T. A1 - Sokhan, M. A1 - Kautek, W. ED - Johann Nimmrichter, ED - Kautek, Wolfgang ED - Manfred Schreiner, T1 - Laser cleaning of undyed silk: Indications of chemical change T2 - LACONA VI - Lasers in the conservation of artworks (Proceedings) T2 - LACONA VI CY - Vienna, Austria DA - 2005-09-21 KW - Laser KW - Cleaning KW - Silk KW - Textiles KW - Viscometry KW - X-ray diffraction KW - SIMS PY - 2007 SN - 978-3-540-72129-1 SN - 0930-8989 N1 - Serientitel: Springer proceedings in physics – Series title: Springer proceedings in physics IS - 116 SP - 313 EP - 319 PB - Springer CY - Berlin AN - OPUS4-16379 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Lussky, K. A1 - Engel, P. A1 - Krüger, Jörg ED - Engel, Patricia T1 - Laser cleaning of artificially soiled paper T2 - Research in book and paper conservation in Europe - a state of the art N2 - Laser cleaning for works of art on paper might be a supplemental, noncontact method to overcome some of the limitations of traditional dry cleaning techniques. Three different types of paper (pure-cellulose filter paper, rag paper, and wood-pulp paper) were mechanically soiled with pulverized charcoal in a standardized procedure to make model samples. These samples were characterized microscopically and by means of lightness measurements using a multi-spectral imaging system. A prototype laser workstation with Laser Class I conditions for the operator was used for the cleaning experiments. For 10-ns laser pulses at a wavelength of 532 nm, a set of laser parameters was established for a successful cleaning of the samples avoiding damage to the paper substrate. Single- and multi-pulse illumination conditions were tested. An extensive microscopic analysis after laser treatment of the cleaned parts of the samples provided insight into the remaining soiling on the surface and in the bulk of the paper material. PY - 2009 SN - 978-3-85028-490-5 SP - 171 EP - 188 PB - Berger Horn CY - Wien, Austria AN - OPUS4-20398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kautek, Wolfgang A1 - Pentzien, Simone A1 - Krüger, Jörg A1 - König, E. ED - Kautek, W. ED - König, E. T1 - Laser cleaning of ancient parchments T2 - Lasers in the conservation of artworks T2 - LACONA I CY - Heraklion, Crete, Greece DA - 1995-10-04 PY - 1997 SN - 3-901025-68-5 VL - 18 SP - 69 EP - 78 PB - Mayer CY - Klosterneuburg AN - OPUS4-11784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jeschke, H.O. A1 - Garcia, M.E. A1 - Lenzner, Matthias A1 - Bonse, Jörn A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Laser ablation thresholds of silicon for different pulse durations: theory and experiment JF - Applied surface science N2 - The ultrafast laser ablation of silicon has been investigated experimentally and theoretically. The theoretical description is based on molecular dynamics (MD) simulations combined with a microscopic electronic model. We determine the thresholds of melting and ablation for two different pulse durations =20 and 500 fs. Experiments have been performed using 100 Ti:Sap-phire laser pulses per spot in air environment. The ablation thresholds were determined for pulses with a duration of 25 and 400 fs, respectively. Good agreement is obtained between theory and experiment. KW - Laser ablation KW - Pulse duration KW - Threshold of silicon PY - 2002 DO - https://doi.org/10.1016/S0169-4332(02)00458-0 SN - 0169-4332 SN - 1873-5584 VL - 197-198 SP - 839 EP - 844 PB - North-Holland CY - Amsterdam AN - OPUS4-6314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kautek, Wolfgang A1 - Krüger, Jörg A1 - Lenzner, M. A1 - Sartania, S. A1 - Spielmann, Ch. A1 - Krausz, F. T1 - Laser ablation of dielectrics with pulse durations between 20 fs and 3 ps JF - Applied physics letters PY - 1996 SN - 0003-6951 SN - 1077-3118 VL - 69 IS - 21 SP - 3146 EP - 3148 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-11496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Niino, Hiroyuki A1 - Yabe, A. T1 - Investigation of excimer laser ablation threshold of polymers using a microphone JF - Applied surface science N2 - KrF excimer laser ablation of polyethylene terephthalate (PET), polyimide (PI) and polycarbonate (PC) in air was studied by an in situ monitoring technique using a microphone. The microphone signal generated by a short acoustic pulse represented the etch rate of laser ablation depending on the laser fluence, i.e., the ablation “strength”. From a linear relationship between the microphone output voltage and the laser fluence, the single-pulse ablation thresholds were found to be 30 mJ cm-2 for PET, 37 mJ cm-2 for PI and 51 mJ cm-2 for PC (20-pulses threshold). The ablation thresholds of PET and PI were not influenced by the number of pulses per spot, while PC showed an incubation phenomenon. A microphone technique provides a simple method to determine the excimer laser ablation threshold of polymer films. KW - Laser ablation KW - Polymer KW - Treshold KW - Microphone KW - Acoustic measurement KW - Incubation PY - 2002 DO - https://doi.org/10.1016/S0169-4332(02)00418-X SN - 0169-4332 SN - 1873-5584 VL - 197-198 SP - 800 EP - 804 PB - North-Holland CY - Amsterdam AN - OPUS4-1920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hertwig, Andreas A1 - Martin, Sven A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Interaction area dependence of the ablation threshold of ion-doped glass JF - Thin solid films N2 - The laser ablation behaviour of ion-doped glass filter materials under irradiation with femtosecond laser pulses was investigated with respect to spot size and repetition rate. The damage threshold fluence of Schott BG18 depends on the size of the irradiated area. The effect is discussed in terms of a defect-site model. KW - Femtosecond KW - Laser KW - Materials processing KW - Ablation KW - Threshold KW - Glass PY - 2004 DO - https://doi.org/10.1016/j.tsf.2003.11.131 SN - 0040-6090 VL - 453-454 SP - 527 EP - 530 PB - Elsevier CY - Amsterdam AN - OPUS4-11046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eberstein, Markus A1 - Mann, Guido A1 - Vogel, Jens A1 - Zoheidi, M. A1 - Krüger, Jörg T1 - Influence of Technological Parameters on Nanosecond Laser-induced Surface Damage of Optical Multimode Fibers JF - Advanced materials research N2 - High-power optical multimode fibers are essential components for materials processing and surgery and can limit the reliability of expensive systems due to breakdown at the end faces. The breakdown threshold of fibers is determined by intrinsic materials properties and parameters of the technology applied. The aim of this paper is the identification of technological parameters that are crucial for the fiber quality. Fibers were drawn from preforms of Heraeus SWU with core material F300 and a low amount of OH-. Both, the cladding (fluorine doped SiO2) to core diameter ratio (CCDR) and the drawing speed were varied. CCDR values between 1.05 and 1.4 were used. Afterwards, the laser-induced damage thresholds (LIDT) of the fibers were determined. For comparison, also samples from preforms, which underwent different thermal treatments above the transition temperature, were tested with respect to their damage resistivity. Single and multi pulse LIDT measurements were done in accordance with the relevant ISO standards. Nd:YAG laser pulses with durations of 15 ns (1064 nm wavelength) and 8.5 ns (532 nm) at a repetition rate of 10 Hz were utilized. For the fibers, LIDT values (1-on-1, 1064 nm and 532 nm) increased with growing CCDR and with decreasing drawing velocities. KW - Silica glass KW - Multimode fiber KW - Nanosecond laser KW - Damage threshold PY - 2005 SN - 1022-6680 SN - 1662-8985 VL - 39-40 SP - 225 EP - 230 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-17339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mann, Guido A1 - Jurke, Mathias A1 - Zoheidi, M. A1 - Krüger, Jörg T1 - Influence of mechanical stress on nanosecond laser-induced damage threshold of fused silica JF - Applied surface science N2 - Optical multimode fibers made of fused silica are widely used for transmission of high power laser pulses. Bending of fibers creates mechanical stress inside the material. The bend stress of a fiber can be calculated from bend radius, geometrical fiber parameters and Young's Modulus of the fiber core material and reaches typically values of 220 MPa. A thermo-elastic model of Kusov et al. predicts a quadratic dependence of laser-induced damage threshold fluence with applied stress. In the present study, fiber preform material F300 (Heraeus) was loaded mechanically with pressures up to 220 MPa representing 20% of the pressure resistance of fused silica. Bulk laser-induced damage thresholds (LIDT) were evaluated using a longitudinal multimode Q-switched Nd:YAG laser (1064 nm) at a pulse duration of 12 ns with polarization states parallel and perpendicular to the stress direction. LIDT of fused silica samples of about 700 J/cm2 were found. LIDT did not show a dependence on mechanical pressure and polarization state which is a consequence of the small ratio of maximum applied stress (220 MPa) to Young's Modulus of fused silica (72.5 GPa). KW - Laser-induced damage threshold KW - LIDT KW - Nanosecond laser KW - Fused silica KW - Mechanical stress KW - Optical fiber PY - 2012 DO - https://doi.org/10.1016/j.apsusc.2012.01.049 SN - 0169-4332 SN - 1873-5584 VL - 258 IS - 23 SP - 9153 EP - 9156 PB - North-Holland CY - Amsterdam AN - OPUS4-26225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Daminelli-Widany, Grazia A1 - Pentzien, Simone A1 - Hertwig, Andreas A1 - Krüger, Jörg T1 - Influence of film thickness on laser ablation of hydrogenated amorphous carbon films JF - Applied physics N2 - Single-pulse damage thresholds of hydrogenated amorphous carbon (a-C:H) films were measured for 8-ns laser pulses at 532-nm wavelength. Layer thicknesses from below the optical penetration depth to above the thermal diffusion length (60 nm–13 µm) were examined. After correction of the damage-threshold values for the fraction of energy effectively absorbed by the material, the damage threshold was found to increase linearly with the layer thickness, also for film thicknesses below the optical penetration depth of a-C:H. The threshold fluence reached the bulk value for a layer thickness equal to the thermal diffusion length. The thermal diffusion coefficient was obtained from fitting the experimental data. Several phenomena like graphitization, blistering, exfoliation, and ablation were observed for different fluence regimes and film thicknesses. PY - 2006 DO - https://doi.org/10.1007/s00339-005-3460-5 SN - 0340-3793 VL - 83 IS - 1 SP - 89 EP - 94 PB - Springer CY - Berlin AN - OPUS4-12022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Koter, Robert A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Influence of film thickness and optical constants on femtosecond laser-induced damage of hydrongenated amorphous carbon films T2 - European Materials Research Society (EMRS), Spring Meeting 2009 T2 - European Materials Research Society (EMRS), Spring Meeting 2009 CY - Strasbourg, France DA - 2009-06-08 PY - 2009 AN - OPUS4-19140 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koter, Robert A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Krüger, Jörg T1 - Influence of film thickness and optical constants on femtosecond laser-induced ablation of hydrogenated amorphous carbon films JF - Journal of optoelectronics and advanced materials N2 - Hydrogenated amorphous carbon layers were deposited on BK7 glass in a plasma-assisted chemical vapor deposition process. Low and high refracting films with thicknesses d ranging from 11 nm to 5.8 µm were produced having refractive indices n between 1.68 and 2.41 and linear absorption coefficients of α~100 cm-1 and α~20000 cm-1 at 800 nm wavelength as a result of different plasma modes. Laser ablation thresholds Fth in dependence on d were determined using 30-fs laser pulses. Low absorbing layers show a constant Fth while Fth increases with rising d up to the optical penetration depth of light α-1 for high absorbing films. KW - Physical radiation damage (61.80.-x) KW - Laser-beam impact phenomena (79.20.Ds) KW - Radiation treatment (81.40.Wx) KW - Carbon (81.05.Uw) KW - Optical constants (78.20.Ci) PY - 2010 SN - 1454-4164 VL - 12 IS - 3 SP - 663 EP - 667 PB - INOE & INFM CY - Bucharest AN - OPUS4-21084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Eberstein, Markus A1 - Zoheidi, M. A1 - Vogel, Jens A1 - Mann, Guido A1 - Krüger, Jörg ED - Wolf, Jonas C. ED - Luka Lange, T1 - Influence of fictive temperature on laser-induced damage of silica glass T2 - Glass Materials Research Progress KW - Silica glass KW - Fictive temperature KW - Multimode fiber KW - Nanosecond laser KW - Damage threshold PY - 2008 SN - 978-1-60456-578-2 IS - Chapter 10 SP - 275 EP - 286 PB - Nova Science Publishers, Inc. CY - New York, USA AN - OPUS4-17903 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 JF - Applied Surface Science 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 - Mann, Guido A1 - Jurke, Mathias A1 - Zoheidi, M. A1 - Eberstein, Markus A1 - Krüger, Jörg T1 - Influence of core diameter and coating material on nanosecond laser-induced damage threshold of optical multimode fibers JF - Journal of optoelectronics and advanced materials N2 - Single and multi pulse laser-induced damage thresholds (LIDT) of core, cladding, and coating materials of high-power optical multimode fibers were determined in accordance with ISO 11254 for 532 nm and 1064 nm wavelength in the 10-ns pulse duration regime with spatial Gaussian beam shape. For all-silica fibers, LIDT increases with rising core diameter in a range between 100-600 µm for a constant cladding-core ratio of 1.2. The damage resistance of the low refracting cladding (0.3 % fluorine doped fused silica) is comparable to the undoped SiO2 core. Coating materials show significantly lower LIDT than light-guiding parts of the fibers. KW - Fiber waveguides (42.81.Qb) KW - Physical radiation damage (61.80.-x) KW - Laser-beam impact phenomena (79.20.Ds) KW - Glasses (81.05.Kf) PY - 2010 SN - 1454-4164 VL - 12 IS - 3 SP - 711 EP - 714 PB - INOE & INFM CY - Bucharest AN - OPUS4-21083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Lenzner, M. A1 - Krausz, F. T1 - Incubation of laser ablation in fused silica with 5-fs pulses JF - Applied physics A N2 - Zusammenfassung The threshold fluences for laser-induced damage of fused silica with single 5-fs pulses from a Ti:sapphire laser system were determined by extrapolating the ablated volume to zero. These thresholds are about 4 times as high as the values previously obtained from multi-shot experiments. This result is interpreted in terms of an irreversible modification of the original material below the single-shot threshold (incubation). KW - Laser PY - 1999 DO - https://doi.org/10.1007/s003390051034 SN - 0947-8396 VL - 69 IS - 4 SP - 465 EP - 466 PB - Springer CY - Berlin AN - OPUS4-799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Sorg, N. A1 - Reif, J. A1 - Kautek, Wolfgang T1 - In situ second harmonic generation measurements during the electrodeposition of Ni on n-Si(111) JF - Applied surface science PY - 1993 SN - 0169-4332 SN - 1873-5584 VL - 69 SP - 388 EP - 392 PB - North-Holland CY - Amsterdam AN - OPUS4-11657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Implications of transient changes of optical and surface properties of solids during femtosecond laser pulse irradiation to the formation of laser-induced periodic surface structures JF - Applied surface science N2 - The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of silicon wafer surfaces by linearly polarized Ti:sapphire femtosecond laser pulses (pulse duration 130 fs, central wavelength 800 nm) is studied experimentally and theoretically. In the experiments, so-called low-spatial frequency LIPSS (LSFL) were found with periods smaller than the laser wavelength and an orientation perpendicular to the polarization. The experimental results are analyzed by means of a new theoretical approach, which combines the widely accepted LIPSS theory of Sipe et al. with a Drude model, in order to account for transient (intra-pulse) changes of the optical properties of the irradiated materials. It is found that the LSFL formation is caused by the excitation of surface plasmon polaritons, SPPs, once the initially semiconducting material turns to a metallic state upon formation of a dense free-electron-plasma in the material and the subsequent interference between its electrical field with that of the incident laser beam resulting in a spatially modulated energy deposition at the surface. Moreover, the influence of the laser-excited carrier density and the role of the feedback upon the multi-pulse irradiation and its relation to the excitation of SPP in a grating-like surface structure is discussed. KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures KW - (LIPSS) KW - Optical properties KW - Surface plasmon polaritons KW - Semiconductors KW - Silicon PY - 2011 DO - https://doi.org/10.1016/j.apsusc.2010.11.059 SN - 0169-4332 SN - 1873-5584 VL - 257 IS - 12 SP - 5420 EP - 5423 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-23309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geier, M. A1 - Eberstein, M. A1 - Grießmann, H. A1 - Partsch, U. A1 - Völkel, L. A1 - Böhme, R. A1 - Mann, Guido A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Impact of laser treatment on phosphoric acid coated multicrystalline silicon PV-wafers T2 - 26th European photovoltaic solar energy conference and exhibition (Proceedings) N2 - The selective emitter is a well-known technology for producing highly doped areas under the metallization grid to improve the solar cell performance. In this work, the influence of laser irradiation on phosphoric acid coated multicrystalline silicon PV-wafers on the wafer surface structure, the phosphorous depth distribution and the electrical contact resistance within the laser treated area as well as the electrical series resistance of laserprocessed solar cells was evaluated. Different laser processing settings were tested including pulsed and continuous wave (cw) laser sources (515 nm, 532 nm, 1064 nm wavelength). Complementary numerical simulations using the finite element method (FEM) were conducted to explain the impact of the laser parameters on the melting behavior (melt duration and geometry). It was found that the melt duration is a key parameter for a successful laser Doping process. Our simulations at a laser wavelengths of 515 nm reveal that low-repetition rate (<500 kHz) laser pulses of 300 ns duration generate a melt duration of ~0.35 µs, whereas upon scanning cw-laser radiation at 532 nm prolongates the melt duration by at least one order of magnitude. Experimentally, the widely used ns-laser pulses did not lead to satisfying laser irradiation results. In contrast, cw-laser radiation and scan velocities of less than 2 m/s led to suitable laser doping featuring low electrical resistances in the laser treated areas. T2 - 26th European photovoltaic solar energy conference and exhibition CY - Hamburg, Germany DA - 05.09.2011 KW - Silicon solar cell KW - Selective emitter KW - Laser processing KW - Doping KW - Simulation PY - 2011 SN - 3-936338-27-2 DO - https://doi.org/10.4229/26thEUPVSEC2011-2BV.1.7 SP - 1243 EP - 1247 AN - OPUS4-24995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 JF - Physica Status Solidi A 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 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Weise, Matthias A1 - Beck, Uwe T1 - Hydrogen-Containing Amorphous Carbon Layers as Optical Materials in the Near-IR Spectral Range JF - Plasma processes and polymers N2 - Hydrogenated amorphous carbon layers were deposited on various substrates by means of a plasma CVD process with a RF substrate bias as well as an ECR plasma source. The optical properties of the a-C:H layers were obtained via spectroscopic ellipsometry and correlated with their mechanical and chemical properties. The layers from pure RF plasma exhibit a higher absorption constant in the visible spectral range and a higher refractive index. All layers are nearly transparent in the NIR spectral range making them candidates for optical thin layer systems. The laser damage behaviour of the a-C:H layers was investigated with ultrashort pulses. The damage thresholds were consistent with the absorption constants of the layers. Interesting damage morphologies were observed indicating a sensitivity of this experiment to sub-structures in the layer. KW - Kohlenstoffschichten KW - Optische Konstanten KW - Ellipsometrie KW - Laser-Material-Bearbeitung KW - Amorphous KW - Diamond-like carbon KW - Hydrocarbons KW - Laser ablation KW - Optical proper PY - 2007 SN - 1612-8850 SN - 1612-8869 VL - 4 IS - S1 SP - S76 EP - S82 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-14862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mann, Guido A1 - Zoheidi, M. A1 - Krüger, Jörg T1 - Hochleistungsfasern am Limit - Laserinduzierte Zerstörung als Einsatzgrenze bei Lichtwellenleitern JF - Laser + Photonik N2 - Aufgrund der steigenden Anforderungen an Fasern für Hochleistungsanwendungen hat die Business Unit Fiber Optics der Leoni Gruppe gemeinsam mit der BAM Bundesanstalt für Materialforschung und -prüfung die Herausforderung angenommen, erstmalig die Zerstörschwellen eigener “large core” Spezialfasern zu untersuchen. KW - Laserinduzierte Zerstörschwelle KW - Optische Multimodefaser KW - Lichtwellenleiter KW - Nanosekundenlaser PY - 2012 UR - http://www.leoni-fiber-optics.com/fileadmin/bu/fo/news/pdf/fachpresse/I-PDF_LP110166_leoni_LP4-12_kleiner_.pdf SN - 1610-3521 VL - 4 SP - 18 EP - 21 PB - Hanser CY - München AN - OPUS4-26424 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mann, Guido A1 - Zoheidi, M. A1 - Krüger, Jörg T1 - High performance fibers at the limit JF - Laser + Photonik N2 - Because of the increasingly stringent requirements for fibers in high Performance applications, the Business Unit Fiber Optics of the Leoni Group and the German BAM Federal Institute for Materials Research and Testing are jointly tackling the challenge of investigating the damage thresholds of selected large core special fibers for the first time. KW - Laser-induced damage threshold KW - Optical multimode fiber KW - Nanosecond laser PY - 2013 SN - 1610-3521 IS - Laser+Photonics Exportausgabe 2013 SP - 20 EP - 23 PB - Hanser CY - München AN - OPUS4-27679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Herstellung von keramischen Implantatbeschichtungen mittels fs-Laserpulsen T2 - Innovationsforum MikroLas T2 - Innovationsforum MikroLas CY - Rostock, Germany DA - 2012-03-06 PY - 2012 AN - OPUS4-25526 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Herausforderungen der Femtosekunden-Technologie an den Laserschutz N2 - Die Verleihung des Deutschen Zukunftspreises an ein Team zum Thema "Ultrakurzpulslaser für die industrielle Massenfertigung - Produzieren mit Lichtblitzen" im Jahr 2013 belegt die industrielle Relevanz des Ultrakurzpulslasereinsatzes in der Materialbearbeitung. Zunehmend werden weitere Anwendungen z.B. in der Mess- und Medizintechnik erschlossen. Femtosekunden-Laserpulse weisen prinzipbedingt ein breites Spektrum auf und besitzen bereits bei moderaten Pulsenergien extreme Pulsspitzenleistungen, womit über „konventionelle“ Laserquellen hinausgehende Herausforderungen an den Laserschutz entstehen. Die in entsprechenden Laserschutzbrillen verwendeten Laserschutzfilter müssen eine große spektrale Absorptionsbandbreite aufweisen und dürfen nicht aufschalten, d.h. keine induzierte Transmission zeigen. Im Vortrag soll dargestellt werden, dass Laserschutzfilter auf Glasbasis, die über ein breites Absorptionsspektrum verfügen, einen ausreichenden Schutz gegenüber fs-Laserstrahlung bieten, wohingegen Laserschutzfilter auf Polymerbasis eine induzierte spektrale Transmission bei steigender Energiedichte aufweisen können, was zu einem drastischen Verlust der Schutzfunktion führt. T2 - Symposium Strahlenschutz – Neue Technologien im Laserschutz CY - BIZBw, Mannheim, Germany DA - 17.11.2015 KW - Laserschutz KW - Schutzbrille KW - Ultrakurzpulslaser KW - Glasfilter KW - Polymerfilter PY - 2015 AN - OPUS4-36259 LA - deu 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 JF - Applied Surface Science 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 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Krivenko, A.G. A1 - Benderskii, V.A. T1 - Gigantic Hydrogen-Ion Discharge Currents Initiated by a Subpicosecond Laser JF - Russian journal of electrochemistry PY - 1998 SN - 0038-5387 SN - 1023-1935 VL - 34 IS - 10 SP - 1068 EP - 1075 PB - MAIK Nauka/Interperiodica Publ. CY - Moscow AN - OPUS4-826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Legall, Herbert A1 - Bonse, Jörn T1 - Gefährdung durch Röntgenstrahlung bei der UKP-Lasermaterialbearbeitung – eine Einführung N2 - Der Vortrag gibt eine Einführung zur Gefährdung durch Röntgenstrahlung bei der Materialbearbeitung mit ultrakurzen Laserpulsen. T2 - LEF - Laser in der Elektronikproduktion & Feinwerktechnik, LEF-Brick 4: Gefährdung durch Röntgenstrahlung bei UKP-Prozessen CY - Online meeting DA - 17.06.2021 KW - Ultrakurze Laserpulse KW - Lasermaterialbearbeitung KW - Röntgenstrahlung KW - Strahlenschutz PY - 2021 AN - OPUS4-52864 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Legall, Herbert A1 - Bonse, Jörn T1 - Gefährdung durch Röntgenstrahlung bei der UKP-Lasermaterialbearbeitung N2 - Der Vortrag beschreibt die Gefährdung durch die Erzeugung unerwünschter Röntgenstrahlung bei der Lasermaterialbearbeitung mit ultrakurzen Laserimpulsen. Die Einfluss der Laserparameter, der Prozessführung und die Materialabhängigkeit werden dargestellt. T2 - Bayerische Laserschutztage 2020 CY - Nuremberg, Germany DA - 21.01.2020 KW - Ultrakurze Laserimpulse KW - Materialbearbeitung KW - Röntgenstrahlung KW - Strahlenschutz PY - 2020 AN - OPUS4-50318 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Gefährdung durch Röntgenemission bei der UKP-Laser-Materialbearbeitung N2 - Der Vortrag gibt einen Überblick zu ultrakurzen Laserpulsen, der Ultrakurzpulslaser-Materialbearbeitung und der dabei ggf. auftretenden unerwünschten Röntgenstrahlung. Es wird die Laserbearbeitung von technischen und biologischen Materialien diskutiert. Schutzmöglichkeiten gegenüber der Röntgenstrahlung werden erörtert. T2 - Sonthofer Strahlenschutztage 2024 CY - Sonthofen, Germany DA - 11.03.2024 KW - Ultrakurzpulslaser KW - Laser-induzierte Röntgenstrahlung KW - Materialbearbeitung KW - Technische Materialien KW - Biologische Anwendungen PY - 2024 AN - OPUS4-59667 LA - deu 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 - Formation of laser-induced periodic surface structures on fused silica upon two-color double-pulse irradiation JF - Applied physics letters N2 - The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences consisting of laser pulse pairs (50 fs single-pulse duration) of two different wavelengths (400 and 800 nm) is studied experimentally. Parallel polarized double-pulse sequences with a variable delay Δt between -10 and +10 ps and between the individual fs-laser pulses were used to investigate the LIPSS periods versus Δt. These two-color experiments reveal the importance of the ultrafast energy deposition to the silica surface by the first laser pulse for LIPSS formation. The second laser pulse subsequently reinforces the previously seeded spatial LIPSS frequencies. PY - 2013 DO - https://doi.org/10.1063/1.4850528 SN - 0003-6951 SN - 1077-3118 VL - 103 IS - 25 SP - 254101-1 EP - 254101-4 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-29812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosenfeld, A. A1 - Rohloff, M. A1 - Höhm, S. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Formation of laser-induced periodic surface structures on fused silica upon multiple parallel polarized double-femtosecond-laser-pulse irradiation sequences JF - Applied surface science N2 - The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences of parallel polarized Ti:sapphire femtosecond laser pulse pairs (160 fs pulse duration, 800 nm central wavelength) was studied experimentally. For that purpose, a Michelson interferometer was used to generate near-equal-energy double-pulse sequences allowing the temporal pulse delay between the parallel-polarized individual fs-laser pulses to be varied between 0 and 40 ps with ~0.2 ps temporal resolution. The surface morphologies of the irradiated surface areas were characterized by means of scanning electron and scanning force microscopy. In the sub-ps delay range a strong decrease of the LIPSS periods and the ablation crater depths with the double-pulse delay was observed indicating the importance of the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Double-pulse experiments KW - Fused silica KW - Michelson interferometer PY - 2012 DO - https://doi.org/10.1016/j.apsusc.2011.09.076 SN - 0169-4332 SN - 1873-5584 VL - 258 IS - 23 SP - 9233 EP - 9236 PB - North-Holland CY - Amsterdam AN - OPUS4-26226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rohloff, M. A1 - Das, S.K. A1 - Höhm, S. A1 - Grunwald, R. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Formation of laser-induced periodic surface structures on fused silica upon multiple cross-polarized double-femtosecond-laser-pulse irradiation sequences JF - Journal of applied physics N2 - The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences consisting of five Ti:sapphire femtosecond (fs) laser pulse pairs (150 fs, 800 nm) is studied experimentally. A Michelson interferometer is used to generate near-equal-energy double-pulse sequences with a temporal pulse delay from -20 to +20 ps between the cross-polarized individual fs-laser pulses (~0.2 ps resolution). The results of multiple double-pulse irradiation sequences are characterized by means of Scanning Electron and Scanning Force Microscopy. Specifically in the sub-ps delay domain striking differences in the surface morphologies can be observed, indicating the importance of the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS. KW - Atomic force microscopy KW - Conduction bands KW - High-speed optical techniques KW - Laser beam effects KW - Scanning electron microscopy KW - Silicon compounds KW - Surface morphology PY - 2011 DO - https://doi.org/10.1063/1.3605513 SN - 0021-8979 SN - 1089-7550 VL - 110 IS - 1 SP - 014910-1 - 014910-4 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-24049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Höhm, S. A1 - Rohloff, M. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Rosenfeld, A. ED - Sakabe, S. ED - Lienau, C. ED - Grunwald, R. T1 - Formation of laser-induced periodic surface structures (LIPSS) on dielectrics and semiconductors upon double-femtosecond laser pulse irradiation sequences T2 - Progress in nonlinear nano-optics N2 - The formation of laser-induced periodic surface structures (LIPSS) on different materials (silicon, fused silica, quartz) with linearly polarized fs-laser irradiation is studied experimentally. In dielectrics, the importance of transient excitation stages in the LIPSS formation is demonstrated by using (multiple) cross-polarized double-fs-laser-pulse irradiation sequences. A characteristic decrease of the spatial LIPSS periods is observed for double-pulse delays of less than 2 ps along with a characteristic 90°-rotation of the LIPSS orientation. PY - 2015 SN - 978-3-319-12216-8 SN - 978-3-319-12217-5 DO - https://doi.org/10.1007/978-3-319-12217-5_5 SN - 2192-1970 N1 - Serientitel: Nano-Optics and Nanophotonics – Series title: Nano-Optics and Nanophotonics SP - Chapter 5, 85 EP - 99 PB - Springer AN - OPUS4-32541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Symietz, Christian A1 - Lehmann, Erhard A1 - Gildenhaar, Renate A1 - Krüger, Jörg A1 - Berger, Georg T1 - Fixierung resorbierbarer Knochenersatzkeramik auf Ti6Al4V-Implantatmaterial mittels Femtosekundenlaser T2 - 5. Thüringer Grenz- und Oberflächentage und 7. Thüringer Biomaterial-Kolloquium T2 - 5. Thüringer Grenz- und Oberflächentage und 7. Thüringer Biomaterial-Kolloquium CY - Friedrichroda, Deutschland DA - 2009-09-15 KW - Metallprothese KW - Implantat KW - Knochenersatz KW - Bioaktives Material KW - Lasersintern KW - Femtosekundenlaser PY - 2009 SN - 978-3-00-028446-5 SP - 327 AN - OPUS4-20051 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Symietz, Christian A1 - Lehmann, Erhard A1 - Gildenhaar, Renate A1 - Berger, Georg T1 - Fixation of bioactive calcium phosphate on Ti6AI4V with e femtosecond laser T2 - Jahrestagung der Deutschen Gesellschaft für Biomaterialien (DGBM) T2 - Jahrestagung der Deutschen Gesellschaft für Biomaterialien (DGBM) CY - Giessen, Germany DA - 2011-11-10 PY - 2011 AN - OPUS4-24893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Symietz, Christian A1 - Lehmann, Erhard A1 - Gildenhaar, Renate A1 - Koter, Robert A1 - Berger, Georg A1 - Krüger, Jörg T1 - Fixation of bioactive calcium alkali phosphate on Ti6Al4V implant material with femtosecond laser pulses JF - Applied surface science N2 - Bone implants made of metal, often titanium or the titanium alloy Ti6Al4V, need to be surface treated to become bioactive. This enables the formation of a firm and durable connection of the prosthesis with the living bone. We present a new method to uniformly cover Ti6Al4V with a thin layer of ceramics that imitates bone material. These calcium alkali phosphates, called GB14 and Ca10, are applied to the metal by dip coating of metal plates into an aqueous slurry containing the fine ceramic powder. The dried samples are illuminated with the 790 nm radiation of a pulsed femtosecond laser. If the laser fluence is set to a value just below the ablation threshold of the ceramic (ca. 0.4 J/cm²) the 30 fs laser pulses penetrate the partly transparent ceramic layer of 20–40 µm thickness. The remaining laser fluence at the ceramic–metal interface is still high enough to generate a thin metal melt layer leading to the ceramic fixation on the metal. The laser processing step is only possible because Ti6Al4V has a lower ablation threshold (between 0.1 and 0.15 J/cm²) than the ceramic material. After laser treatment in a fluence range between 0.1 and 0.4 J/cm², only the particles in contact with the metal withstand a post-laser treatment (ultrasonic cleaning). The non-irradiated rest of the layer is washed off. In this work, we present results of a successful ceramic fixation extending over larger areas. This is fundamental for future applications of arbitrarily shaped implants. KW - Bone implant KW - Bioceramic coating KW - Titanium KW - Calcium phosphate KW - Femtosecond laser PY - 2011 DO - https://doi.org/10.1016/j.apsusc.2010.10.046 SN - 0169-4332 SN - 1873-5584 VL - 257 IS - 12 SP - 5208 EP - 5212 PB - North-Holland CY - Amsterdam AN - OPUS4-23310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Femtosecond-pulse visible laser processing of transparent materials JF - Applied surface science N2 - High-power lasers in industrial and R & D applications raise the general problem of reliability and degradation of optical components. A systematic study of nonlinear interaction of various transparent dielectric materials as e.g. glasses, fused silica, and polymers, with laser-pulses in the intensity range of up to 1013 W cm-2 is presented. On the other hand, femtosecond-pulse laser processing in the visible spectral range (300 fs; 620 nm, ~ 2 eV) allows precise microstructuring of transparent dielectrics without disruption of the remnant material. Damage and ablation threshold fluences occur above 1.2 J cm-2 at both silicate glasses and fused silica. Two different photon absorption mechanisms have been observed. The first occurs during the initial laser pulses in the incubation range. There, multiphoton absorption results in moderate energy volume densities. These are sufficient to generate morphological changes and optically active defect sites (colour centres) which provide a much higher absorptivity relevant for the second mechanism. It results in gasification without participation of melt. PY - 1996 SN - 0169-4332 SN - 1873-5584 VL - 96-98 SP - 430 EP - 438 PB - North-Holland CY - Amsterdam AN - OPUS4-11509 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Jörg A1 - Kautek, Wolfgang ED - Dubowski, J. T1 - Femtosecond-pulse laser processing of metallic and semiconducting thin films T2 - Laser-induced thin film processing KW - Femtosekundenpulslaser KW - Pulslaser KW - Dünnschicht, metallisch KW - Dünnschicht, halbleitend KW - Ablation PY - 1995 SN - 0-8194-1750-5 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 2403 SP - 436 EP - 447 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kautek, Wolfgang A1 - Krüger, Jörg ED - Brieger, M. T1 - Femtosecond-pulse laser microstructuring of semiconducting materials T2 - Semiconductor processing and characterization with lasers T2 - 1st International Symposium on Semiconductor Processing and Characterization with Lasers - Applications in Photovoltaics CY - Stuttgart, Germany DA - 1994-04-18 KW - Femtosecond-Pulse Laser KW - Subpicosecond-Pulse Laser KW - Laser-Ablation KW - Multi-Photon Absorption KW - Microstructuring KW - Dry Etching KW - Semiconductors KW - Silicon PY - 1995 SN - 0-87849-683-1 SN - 0255-5476 N1 - Serientitel: Materials science forum – Series title: Materials science forum IS - 173/174 SP - 17 EP - 22 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-11671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Staub, M. A1 - Scherer, G.G. ED - Waidelich, W. T1 - Femtosecond-pulse laser micromachining of metal layer composites T2 - Laser in Forschung und Technik = Laser in research and engineering T2 - 12. Internationalen Kongresses Laser 95 CY - Berlin, Germany DA - 1996-01-01 PY - 1996 SN - 3-540-61316-1 SP - 966 EP - 969 PB - Springer CY - Berlin AN - OPUS4-11958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Baudach, Steffen A1 - Kautek, Wolfgang A1 - Lenzner, M. A1 - Wrobel, J. M. T1 - Femtosecond-Pulse Laser Machining of Semiconducting Materials T2 - Conference digest N2 - Summary form only given. Machining investigations of crystalline silicon have been performed with laser pulses at a wavelength of 780 nm in the range between 5 fs and 400 fs. Applying 100 pulses per spot, surface damage thresholds were determined by the measurement of the damage diameter. In this pulse duration regime, the threshold fluences were nearly constant. Single-pulse investigations with 5 fs pulses yielded a value of about 0.15 J cm-2 identical to the multi-pulse experiment. This is in contradiction to the behaviour of dielectrics where incubation effects alter the optical properties down to the 5 fs pulse regime. Employing laser pulses with a duration of 130 fs at a wavelength of 800 nm, single-pulse ablation thresholds of 0.23 J cm-2 and 0.16 J cm-2 were determined for Si and InP in air, respectively. The threshold fluence was calculated from the linear relation between the square of the diameters versus the logarithm of the laser fluences. T2 - CLEO/Europe 2000 ; Conference on Lasers and Electro-Optics Europe ; Conférence Européenne sur les Lasers et l'Electro-Optique ; CLEO/Europe-IQEC CY - Nice, France DA - 2000-09-10 PY - 2000 SN - 0-7803-6319-1 DO - https://doi.org/10.1109/CLEOE.2000.910410 PB - IEEE Service Center CY - Piscataway, NJ AN - OPUS4-958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kautek, Wolfgang A1 - Mitterer, S. A1 - Krüger, Jörg A1 - Husinsky, W. A1 - Grabner, G. T1 - Femtosecond-Pulse Laser Ablation of Human Corneas JF - Applied physics A N2 - A femtosecond pulse laser in the visible spectral region shows promise as a potentially new powerful corneal sculpting tool. It combines the clinical and technical advantages of visible wavelengths with the high ablation quality observed with nanosecond-pulse excimer lasers at 193 nm. A femtosecond and a nanosecond dye laser with pulse durations of 300 fs and 7 ns, and centre wavelengths at 615 nm and 600 nm, respectively, both focused to an area of the order of 10–5 cm2, have been applied to human corneal ablation. Nanosecond laser pulses caused substantial tissue disruption within a 30–100 m range from the excision edge at all fluences above the ablation threshold of F th60 J cm–2 (I th9 GW cm–2). Completely different excisions are produced by the femtosecond-pulse laser: high quality ablations of the Bowman membrane and the stroma tissue characterised by damage zones of less than 0.5 m were observed at all fluences above ablation threshold of F th1 J cm–2 or I th3 TW cm–2 (3×1012 W cm–2). The transparent cornea material can be forced to absorb ultrashort pulses of extremely high intensity. The fs laser generates its own absorption by a multiphoton absorption process. PY - 1994 DO - https://doi.org/10.1007/BF00332446 SN - 0947-8396 VL - 58 IS - 5 SP - 513 EP - 518 PB - Springer CY - Berlin AN - OPUS4-11659 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Newesely, H. T1 - Femtosecond-pulse laser ablation of dental hydroxyapatite and single-crystalline fluoroapatite JF - Applied physics A N2 - Laser microdrilling of healthy human enamel and dentine using 300 fs pulses at a wavelength of 615 nm and 3 Hz repetition rate leads to an enhanced structuring quality in comparison with nanosecond-laser results. Microcracking and damage to neighboring tissue can be reduced. Ablation threshold fluences for 100 laser pulses of 0.3 J cm-2 (human dentine), 0.6 J cm-2 (human enamel) and 0.8 J cm-2 (single crystalline fluoroapatite) could be determined. Ablation depths per pulse below 1 7m were observed. T2 - 5th International Conference on Laser Ablation ; COLA '99 CY - Göttingen, Germany DA - 1999-07-19 PY - 1999 DO - https://doi.org/10.1007/s003390051426 SN - 0947-8396 VL - 69 IS - 7 SP - S403 EP - S407 PB - Springer CY - Berlin AN - OPUS4-779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudolph, Pascale A1 - Bonse, Jörn A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Femtosecond- and nanosecond-pulse laser ablation of bariumalumoborosilicate glass JF - Applied physics A N2 - Laser ablation with femtosecond pulses (130 fs, wavelength 800 nm, repetition rate 2 Hz) was compared with nanosecond-pulse ablation (10 ns, wavelength 266 nm, repetition rate 2.5 Hz) of bariumalumoborosilicate glass in air using the direct focusing technique. Different ablation thresholds and heat-affected zones were observed. The lateral and vertical machining precision was evaluated. Single nanosecond laser pulses in the far UV resulted in a bubble or a circular hole in the centre of the illuminated spot, depending on the applied fluence. The ablation behaviour in the case of near-IR femtosecond pulses contrasted to this. Bubble formation was not detected. It needed repeated pulses at the same spot to modify the surface until material removal could be observed (incubation). Cavity dimensions of less than the beam diameter were achieved in this case. T2 - 5th International Conference on Laser Ablation ; COLA '99 CY - Göttingen, Germany DA - 1998-07-19 KW - Laser ablation KW - Bariumalumoborosilicate glass PY - 1999 DO - https://doi.org/10.1007/s003390051524 SN - 0947-8396 VL - 69 IS - 7 SP - S763 EP - S766 PB - Springer CY - Berlin AN - OPUS4-801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Koter, Robert T1 - Femtosecond, picosecond and nanosecond pulse laser cleaning of artificially soiled paper model samples T2 - Konferenz "Laser in the Conservation of Artworks" (LACONA IX) T2 - Konferenz "Laser in the Conservation of Artworks" (LACONA IX) CY - London, England DA - 2011-09-07 PY - 2011 AN - OPUS4-24238 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Femtosecond pulse visible laser processing of fibre composite materials JF - Applied surface science N2 - A first investigation on the ablation of composite materials like carbon and silicon-carbide reinforced alumo- and borosilicate glasses by 300 fs laser pulses (620 nm) in comparison to experiments with 17 ns pulse excimer laser (308 nm) treatment is presented. In all composites, femtosecond laser scans with a fluence of less than 2 J cm-2 produce well defined cuts with smooth side walls in contrast to the nanosecond laser result where extremely incongruent ablation is observed. Visible lasers should not be applicable because SiC and the glasses are practically transparent. Visible subpicosecond pulses of high intensity in the TW cm-2 range allow multi-photon absorption accompanied by incubation phenomena. The morphology of the groove edges reveal the contrasting ablation thresholds and rates of the fibre and glass materials. The ablation thresholds of the transparent components, i.e. the glass matrices and SiC, are about one order of magnitude greater than that of carbon which is ~ 0.15 J cm-2. Incubation effects are important for the absorption mechanisms in the transparent materials. When a critical number of pulses has not been reached at the SiC-glass composites, only the glass is preferentially ablated, and the fibres remain intact. This is in contrast to the C-glass composites where the ablation behaviour is opposite. PY - 1996 SN - 0169-4332 SN - 1873-5584 VL - 106 SP - 383 EP - 389 PB - North-Holland CY - Amsterdam AN - OPUS4-11506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kautek, Wolfgang A1 - Sorg, N. A1 - Krüger, Jörg T1 - Femtosecond pulse laser second harmonic generation on semiconductor electrodes JF - Electrochimica acta KW - Femtosecond pulse laser KW - Second harmonic generation (SHG) KW - Electrochemistry KW - Semiconductor electrode KW - Silicon KW - Silicon oxide KW - Oxide growth PY - 1994 SN - 0013-4686 SN - 1873-3859 VL - 39 IS - 8/9 SP - 1245 EP - 1249 PB - Elsevier Science CY - Kidlington AN - OPUS4-11660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Rudolph, Pascale A1 - Krüger, Jörg A1 - Baudach, Steffen A1 - Kautek, Wolfgang T1 - Femtosecond pulse laser processing of TiN on silicon JF - Applied surface science N2 - Ultrashort pulse laser microstructuring (pulse duration 130 fs, wavelength 800 nm, repetition rate 2 Hz) of titanium nitride (TiN) films on silicon substrates was performed in air using the direct focusing technique. The lateral and vertical precision of laser ablation was evaluated. The TiN ablation threshold changed with the number of pulses applied to the surface due to an incubation effect. An ablation depth per pulse below the penetration depth of light was observed. Columnar structures were formed in the silicon substrate after drilling through the TiN layer. KW - Femtosecond laser ablation KW - Titanium nitride KW - Silicon KW - Optical properties PY - 2000 DO - https://doi.org/10.1016/S0169-4332(99)00481-X SN - 0169-4332 SN - 1873-5584 VL - 154-155 SP - 659 EP - 663 PB - North-Holland CY - Amsterdam AN - OPUS4-802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bonse, Jörn A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Wrobel, J. M. T1 - Femtosecond pulse laser machining of InP wafers T2 - Laser applications in microelectronic and optoelectronic manufacturing V N2 - Ablation of indium phosphide wafers in air was performed with 130 fs laser pulses at a wavelength of 800 nm at a low repetition rate of 10 Hz. In order to evaluate the role of the incubation effects, the relationship between the number of laser pulses used for the ablation and the threshold fluence was studied. Particular attention was paid to the chemical composition, surface morphology and structural variations of the ablated area. T2 - 5th Laser Applications in Microelectronics and Optoelectronics Manufacturing Conference (LAMOM) CY - San José, CA, USA DA - 240.01.2000 KW - Femtosecond laser ablation KW - Indium phosphide KW - Auger electron spectroscopy PY - 2000 SN - 0-8194-3550-3 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 3933 SP - 280 EP - 287 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kautek, Wolfgang A1 - Krüger, Jörg ED - Beyer, E. T1 - Femtosecond pulse laser ablation of metallic, semiconducting, ceramic, and biological materials T2 - Laser materials processing N2 - Production of holes and grooves of < 30 micrometers diameter with high aspect ratio value is a delicate task either for mechanical tools, or for conventional nanosecond pulse lasers like e.g. pulsed Nd:YAG or excimer lasers. They later tend to cause microcracks extending from an annular melting zone, or substantial disruption, respectively. Experimental results are presented which demonstrate that the development of intense ultrashort pulse laser systems (>> 1012 W cm-2, (tau) < 1 ps) opens up possibilities for materials processing by cold plasma generation and ablation of metals, semiconductors, ceramics, composites, and biological materials. A femtosecond and a nanosecond dye laser with pulse durations of 300 fs (< 200 (mu) J) and 7 ns (< 10 mJ), and center wavelengths at 612 and 600 nm, respectively, both focused on an area of the order of 10-5 cm2, have been applied either to absorbing substrates, like polycrystalline gold, silicon (111), aluminum nitride ceramics, or transparent materials, like synthetic and human dental hydroxyapatite composites, bone material, and human cornea transplants. The fs-laser generates its own absorption in transparent materials by a multiphoton absorption process, and thus forces the absorption of visible radiation. Because the time is too short (< ps) for significant transport of mass and energy, the beam interaction generally results in the formation of a thin plasma layer of approximately solid state density. Only after the end of the subpicosecond laser pulse, it expands rapidly away from the surface without any light absorption and further plasma heating. Therefore, energy transfer (heat and impulse) to the target material, and thermal and mechanical disruption are minimized. In contrast to heat- affected zones (HAZ's) generated by conventional nanosecond pulse lasers of the order of 1 - 10 micrometers , HAZ's of less than 0.02 micrometers were observed. T2 - Conference on Production Line Processes ; Conference on Process Control and Modeling ; Conference on Novel Applications CY - Vienna, Austria DA - 1994-04-05 PY - 1994 SN - 0-8194-1508-1 DO - https://doi.org/10.1117/12.184768 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 2207 SP - 600 EP - 611 PB - SPIE--the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-11892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Meja, P. A1 - Autric, M. A1 - Kautek, Wolfgang T1 - Femtosecond pulse laser ablation of anodic oxide coatings on aluminium alloys with on-line acoustic observation JF - Applied surface science N2 - The 125-fs laser ablation behaviour (800 nm) of aluminium and anodic oxide coatings on an AlMgSi1 alloy was investigated. The multi-pulse ablation threshold of aluminium at 1.2 J cm-2 was less than that of the oxides of 2–3 J cm-2. Aluminium exhibited a single pulse modification (melting) threshold of 0.3 J cm-2. These values derived from an evaluation of the crater geometry coincided with on-line acoustic measurements. The detected microphone voltage amplitude increased linearly with the laser fluence. The morphology of the ablation craters on aluminium indicated melt formation and displacement of a homogeneous melt phase due to the recoil action of the expanding metal vapour. The laser-processed ceramic oxide phases, on the other hand, showed a spongy resolidified melt layer, which denotes a collocated in-depth formation both of a melt and a gas phase. These phenomena are discussed in terms of the relative dominance of penetration depth of laser light and heat affected zones in the investigated materials with strongly varying optical and thermodynamical properties. KW - Laser ablation KW - Acoustic measurement KW - Microphone KW - Aluminium KW - Aluminium oxide PY - 2002 SN - 0169-4332 SN - 1873-5584 VL - 186 IS - 1-4 SP - 374 EP - 380 PB - North-Holland CY - Amsterdam AN - OPUS4-6324 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lenzner, Matthias A1 - Krüger, Jörg A1 - Sartania, S. A1 - Cheng, Z. A1 - Spielmann, Ch. A1 - Mourou, G. A1 - Kautek, Wolfgang A1 - Krausz, F. T1 - Femtosecond Optical Breakdown in Dielectrics JF - Physical review letters N2 - We report measurements of the optical breakdown threshold and ablation depth in dielectrics with different band gaps for laser pulse durations ranging from 5 ps to 5 fs at a carrier wavelength of 780 nm. For tau <100 fs, the dominant channel for free electron generation is found to be either impact or multiphoton ionization (MPI) depending on the size of the band gap. The observed MPI rates are substantially lower than those predicted by the Keldysh theory. We demonstrate that sub-10-fs laser pulses open up the way to reversible nonperturbative nonlinear optics (at intensities greater than 1014 W/cm2 slightly below damage threshold) and to nanometer-precision laser ablation (slightly above threshold) in dielectric materials. PY - 1998 SN - 0031-9007 SN - 1079-7114 VL - 80 IS - 18 SP - 4076 EP - 4079 PB - American Physical Society CY - Ridge, NY AN - OPUS4-11518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Bonse, Jörn A1 - Höhm, S. A1 - Hartelt, Manfred A1 - Spaltmann, Dirk A1 - Pentzien, Simone A1 - Koter, Robert A1 - Marschner, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg ED - König, K. ED - Ostendorf, A. T1 - Femtosecond laser-induced surface nanostructures for tribological applications T2 - Optically induced nanostructures: Biomedical and technical applications N2 - Laser-induced periodic surface structures (LIPSS) were generated on two types of steel (100Cr6, X30CrMoN15-1) and two types of titanium (Ti, Ti6A14V) surfaces upon irradiation with multiple linear polarized femtosecond laser pulses in air environment (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz, Gaussian beam shape). Teh conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas covered homogeneously by two different types of LIPSS - either near wavelength or sub-100 nm structures. The tribological performance of the nanostructured surfaces was characterized under reciprocating sliding at 1 Hz against a ball of hardened steel using different lubricants and normal forces. After 1000 cycles the corresponding wear tracks were characterized by optical and scanning electron microscopy. For specific conditions, the wear was strongly reduced and laser-generated nanostructures endured the tribological treatment. Simultaneously, a significant reduction of the friction coefficient was observed in the laser-irradiated LIPSS-covered areas, indicating the benefit of laser surface structuring for tribological applications. The spatially Gaussian shaped beam used for the laser processing was transformed via beam shaping into a top hat distribution at the surface of the samples for optimization. The tribological performance of the laser-induced nanostructures is discussed on the basis of different physical and chemical mechanisms. PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-332647 SN - 978-3-11-033718-1 SN - 978-3-11-035432-4 DO - https://doi.org/10.1515/9783110354324-011 SP - Chapter 7, 141 EP - 156 PB - De Gruyter AN - OPUS4-33264 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 JF - Thin solid films 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 DO - 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 - CONF A1 - Bonse, Jörn A1 - Rosenfeld, A. A1 - Krüger, Jörg ED - Panchenko, V. ED - Mourou, G. ED - Zheltikov, A. M. T1 - Femtosecond laser-induced periodic surface structures: recent approaches to explain their sub-wavelength periodicities T2 - LAT 2010 - International Conference on Lasers, Applications, and Technologies (Proceedings of SPIE) N2 - The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of semiconductors and dielectrics by linearly polarized high-intensity Ti:sapphire fs-laser pulses (τ ~100 fs, λ ~800 nm) is studied experimentally and theoretically. In the experiments, two different types of LIPSS exhibiting very different spatial periods are observed (socalled LSFL – low spatial frequency LIPSS, and HSFL - high spatial frequency LIPSS), both having a different dependence on the incident laser fluence and pulse number per spot. The experimental results are analyzed by means of a new theoretical approach, which combines the generally accepted LIPSS theory of J. E. Sipe and co-workers [Phys. Rev. B 27, 1141-1154 (1983)] with a Drude model, in order to account for transient changes of the optical properties of the irradiated materials. The joint Sipe-Drude model is capable of explaining numerous aspects of fs-LIPSS formation, i.e., the orientation of the LIPSS, their fluence dependence as well as their spatial periods. The latter aspect is specifically demonstrated for silicon crystals, which show experimental LSFL periods Λ somewhat smaller than λ. This behaviour is caused by the excitation of surface plasmon polaritons, SPP, (once the initially semiconducting material turns to a metallic state upon formation of a dense free-electron-plasma in the material) and the subsequent interference between its electrical fields with that of the incident laser beam, resulting in a spatially modulated energy deposition at the surface. Upon multi-pulse irradiation, a feedback mechanism, caused by the redshift of the resonance in a grating-assisted SPP excitation, is further reducing the LSFL spatial periods. The SPP-based mechanism of LSFL successfully explains the remarkably large range of LSFL periods between ~0.6 λ and λ. T2 - LAT 2010 - International Conference on Lasers, Applications, and Technologies CY - Kazan, Russia DA - 23.08.2010 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Surface plasmon polaritons KW - Second harmonic generation (SHG) KW - Silicon KW - Semiconductors KW - Dielectrics PY - 2011 DO - https://doi.org/10.1117/12.879813 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 7994 SP - 79940M-1 EP - 79940M-10 CY - Bellingham, USA AN - OPUS4-23291 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 JF - Applied Surface Science 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 - Bonse, Jörn A1 - Koter, Robert A1 - Hartelt, Manfred A1 - Spaltmann, Dirk A1 - Pentzien, Simone A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications JF - Applied physics A N2 - Laser-induced periodic surface structures (LIPSS, ripples) were generated on stainless steel (100Cr6) and titanium alloy (Ti6Al4V) surfaces upon irradiation with multiple femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas (5 × 5 mm²) covered homogeneously by the nanostructures. The irradiated surface regions were subjected to white light interference microscopy and scanning electron microscopy revealing spatial periods around 600 nm. The tribological performance of the nanostructured surface was characterized by reciprocal sliding against a ball of hardened steel in paraffin oil and in commercial engine oil as lubricants, followed by subsequent inspection of the wear tracks. For specific conditions, on the titanium alloy a significant reduction of the friction coefficient by a factor of more than two was observed on the laser-irradiated (LIPSS-covered) surface when compared to the non-irradiated one, indicating the potential benefit of laser surface structuring for tribological applications. PY - 2014 DO - https://doi.org/10.1007/s00339-014-8229-2 SN - 0947-8396 VL - 117 IS - 1 SP - 103 EP - 110 PB - Springer CY - Berlin AN - OPUS4-31450 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 - Femtosecond laser-induced periodic surface structures on silicon upon polarization controlled two-color double-pulse irradiation JF - Optics express N2 - Two-color double-fs-pulse experiments were performed on silicon wafers to study the temporally distributed energy deposition in the formation of laser-induced periodic surface structures (LIPSS). A Mach-Zehnder interferometer generated parallel or cross-polarized double-pulse sequences at 400 and 800 nm wavelength, with inter-pulse delays up to a few picoseconds between the sub-ablation 50-fs-pulses. Multiple two-color double-pulse sequences were collinearly focused by a spherical mirror to the sample. The resulting LIPSS characteristics (periods, areas) were analyzed by scanning electron microscopy. A wavelength-dependent plasmonic mechanism is proposed to explain the delay-dependence of the LIPSS. These two-color experiments extend previous single-color studies and prove the importance of the ultrafast energy deposition for LIPSS formation. PY - 2015 DO - https://doi.org/10.1364/OE.23.000061 SN - 1094-4087 VL - 23 IS - 1 SP - 61 EP - 71 PB - Optical Society of America CY - Washington, DC AN - OPUS4-32405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Femtosecond laser-induced periodic surface structures on silica JF - Journal of applied physics N2 - The formation of laser-induced periodic surface structures (LIPSS) on two different silica polymorphs (single-crystalline synthetic quartz and commercial fused silica glass) upon irradiation in air with multiple linearly polarized single- and double-fs-laser pulse sequences (τ = 150 fs pulse duration, λ = 800nm center wavelength, temporal pulse separation Δt < 40 ps) is studied experimentally and theoretically. Two distinct types of fs-LIPSS [so-called low-spatial-frequency LIPSS (LSFL) and high-spatial-frequency LIPSS (HSFL)] with different spatial periods and orientations were identified. Their appearance was characterized with respect to the experimental parameters peak laser fluence and number of laser pulses per spot. Additionally, the 'dynamics' of the LIPSS formation was addressed in complementary double-fs-pulse experiments with varying delays, revealing a characteristic change of the LSFL periods. The experimental results are interpreted on the basis of a Sipe-Drude model considering the carrier dependence of the optical properties of fs-laser excited silica. This new approach provides an explanation of the LSFL orientation parallel to the laser beam polarisation in silica—as opposed to the behaviour of most other materials. KW - High-speed optical techniques KW - Laser beam effects KW - Refractive index KW - Silicon compounds KW - Surface structure PY - 2012 DO - https://doi.org/10.1063/1.4730902 SN - 0021-8979 SN - 1089-7550 VL - 112 IS - 1 SP - 014901-1 - 014901-9 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Krüger, Jörg A1 - Höhm, S. A1 - Rosenfeld, A. T1 - Femtosecond laser-induced periodic surface structures JF - Journal of laser applications N2 - The formation of laser-induced periodic surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ~30–150 fs, λ~800 nm) in air environment is studied experimentally and theoretically. In metals, predominantly low-spatial-frequency-LIPSS with periods close to the laser wavelength λ are observed perpendicular to the polarization. Under specific irradiation conditions, high-spatial-frequency-LIPSS with sub-100-nm spatial periods (~λ/10) can be generated. For semiconductors, the impact of transient changes of the optical properties to the LIPSS periods is analyzed theoretically and experimentally. In dielectrics, the importance of transient excitation stages in the LIPSS formation is demonstrated experimentally using (multiple) double-fs-laser-pulse irradiation sequences. A characteristic decrease of the LIPSS periods is observed for double-pulse delays of less than 2 ps. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Ultrafast optical techniques KW - Silicon KW - Titanium KW - Silica PY - 2012 DO - https://doi.org/10.2351/1.4712658 SN - 1042-346X SN - 1938-1387 VL - 24 IS - 4 SP - 042006-1 EP - 042006-7 PB - Laser Institute of America CY - Orlando, Fla., USA AN - OPUS4-26198 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 JF - Applied Physics A 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 -