TY - JOUR A1 - Bonse, Jörn A1 - Baudach, Steffen A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Lenzner, Matthias T1 - Femtosecond laser ablation of silicon-modification thresholds and morphology N2 - We investigated the initial modification and ablation of crystalline silicon with single and multiple Ti:sapphire laser pulses of 5 to 400 fs duration. In accordance with earlier established models, we found the phenomena amorphization, melting, re-crystallization, nucleated vaporization, and ablation to occur with increasing laser fluence down to the shortest pulse durations. We noticed new morphological features (bubbles) as well as familiar ones (ripples, columns). A nearly constant ablation threshold fluence on the order of 0.2 J/cm2 for all pulse durations and multiple-pulse irradiation was observed. For a duration of ,100 fs, significant incubation can be observed, whereas for 5 fs pulses, the ablation threshold does not depend on the pulse number within the experimental error. For micromachining of silicon, a pulse duration of less than 500 fs is not advantageous. PY - 2002 DO - https://doi.org/10.1007/s003390100893 SN - 0947-8396 VL - 74 IS - 1 SP - 19 EP - 25 PB - Springer CY - Berlin AN - OPUS4-6328 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 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 - Dorronsoro, C. A1 - Bonse, Jörn A1 - Siegel, J. T1 - Self-assembly of a new type of periodic surface structure in a copolymer by excimer laser irradiation above the ablation threshold N2 - We report self-assembly of periodic surface structures in a commercial block copolymer (BCP) (Filofocon A) upon irradiation with a few tens of excimer laser pulses (20 ns, 193 nm) at fluences above the ablation threshold. This new type of structures is characterized by much larger periods than those characteristic for Laser-Induced Periodic Surface Structures (LIPSS) and features nanochains instead of ripples. We find a period of 790?nm at 400 mJ/cm², scaling linearly with laser fluence up to a maximum of 1.0 µm. While an entangled random network of nanochains is produced for normal-incidence and non-polarized light, nanochain alignment can be achieved either by irradiation at an angle or by using linearly polarized light, forming a lamella-like structure. In both cases, the nanochains are aligned parallel to the penetrating polarization orientation and their period does not show a dependence on the angle of incidence, as opposed to the general behavior of standard LIPSS. Also, our results show that the chains are not formed by frozen capillary waves. In contrast, we show analogies of the nanochains produced to lamellar structures fabricated on a smaller scale in other BCP. We discuss the origin of the self-assembly process in terms of a combination of chemical (BCP), optical (surface scattering), and thermal (melting, coarsening, and ablation) effects. PY - 2013 UR - http://scitation.aip.org/content/aip/journal/jap/114/15/10.1063/1.4825128 DO - https://doi.org/10.1063/1.4825128 SN - 0021-8979 SN - 1089-7550 VL - 114 SP - 153105-1 - 153105-7 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-29395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Seuthe, T. A1 - Grehn, M. A1 - Mermillod-Blondin, A. A1 - Bonse, Jörn A1 - Eberstein, M. T1 - Compositional dependent response of silica-based glasses after femtosecond laser pulse irradiation N2 - Femtosecond laser pulse irradiation of inorganic glasses allows a selective modification of the optical properties with very high precision. This results in the possibility for the production of three-dimensional functional optical elements in the interior of glass materials, such as optical data storage, waveguide writing, etc. The influence of the chemical glass composition to the response upon ultrashort laser irradiation has not been studied systematically. For that, simple silicabased model glasses composed of systematically varying alkaline- and earth-alkaline components were prepared, irradiated on the surface and in the volume with single fs-laser pulses (~130 fs, 800 nm), and were subsequently analyzed by means of micro-Raman spectroscopy and quantitative phase contrast microscopy in order to account for changes in the glass structure and for alterations of the optical refractive index, respectively. The Raman spectroscopic studies of the laser-irradiated spots revealed no change in the average binding configuration (the so called Q-structure), but local changes of bond-angles and bond-lengths within the glass structure structure. Those changes are explained by structural relaxation of the glass network due to densification caused by a transient laser-induced plasma generation and the following shock wave and other thermal phenomena. Glasses with a low amount of network modifiers show changes in the Si-O network while glasses with a high amount of network modifiers react primarily via variation of the nonbridging oxygen ions. The results are discussed in terms of possible structural response mechanisms and conclusions are outlined regarding glass compositions with technical suitability for fs-laser modifications. T2 - Laser-induced damage in optical materials CY - Boulder, Colorado, USA DA - 2013-09-22 KW - Femtosecond laser modifications KW - Raman spectroscopy KW - Glass KW - Femtosecond phenomena KW - Networks KW - Silica KW - Laser irradiation KW - Lasers KW - Micro raman spectroscopy KW - Microscopy KW - Optical components KW - Optical storage PY - 2013 DO - https://doi.org/10.1117/12.2028713 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series VL - 8885 SP - 1 EP - 8(?) AN - OPUS4-29539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grehn, M. A1 - Seuthe, T. A1 - Tsai, W.-J. A1 - Höfner, M. A1 - Achtstein, A. W. A1 - Mermillod-Blondin, A. A1 - Eberstein, M. A1 - Eichler, H.J. A1 - Bonse, Jörn T1 - Nonlinear absorption and refraction of binary and ternary alkaline and alkaline earth silicate glasses N2 - Nonlinear optical properties such as the nonlinear refractive index and nonlinear absorption are characterized by z-scan measurements for a series of silicate glasses upon irradiation with laser pulses of 130 fs duration and 800 nm center wavelength. The stoichiometry of the silicate glasses is varied systematically to reveal the influence of the glass composition on the nonlinear optical properties. Additionally, the thermal properties such as glass–transformation temperature and thermal expansion coefficient are obtained from dilatometric measurements. It is found that the nonlinear refractive index is mainly related to the silica matrix. The nonlinear absorption is increased with the addition of network–forming ions. PY - 2013 DO - https://doi.org/10.1364/OME.3.002132 SN - 2159-3930 VL - 3 IS - 12 SP - 2132 EP - 2140 PB - OSA CY - Washington, DC AN - OPUS4-29649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Derrien, Thibault A1 - Krüger, Jörg A1 - Itina, T.E. A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Bonse, Jörn T1 - Rippled area formed by surface plasmon polaritons upon femtosecond laser double-pulse irradiation of silicon N2 - The formation of near-wavelength laser-induced periodic surface structures (LIPSS) on silicon upon irradiation with sequences of Ti:sapphire femtosecond laser pulse pairs (pulse duration 150 fs, central wavelength 800 nm) is studied theoretically. For this purpose, the nonlinear generation of conduction band electrons in silicon and their relaxation is numerically calculated using a two-temperature model approach including intrapulse changes of optical properties, transport, diffusion and recombination effects. Following the idea that surface plasmon polaritons (SPP) can be excited when the material turns from semiconducting to metallic state, the 'SPP active area' is calculated as function of fluence and double-pulse delay up to several picoseconds and compared to the experimentally observed rippled surface areas. Evidence is presented that multi-photon absorption explains the large increase of the rippled area for temporally overlapping pulses. For longer double-pulse delays, relevant relaxation processes are identified. The results demonstrate that femtosecond LIPSS on silicon are caused by the excitation of SPP and can be controlled by temporal pulse shaping. PY - 2013 DO - https://doi.org/10.1364/OE.21.029643 SN - 1094-4087 VL - 21 IS - 24 SP - 29643 EP - 29655 PB - Optical Society of America CY - Washington, DC AN - OPUS4-29650 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - On the role of surface plasmon polaritons in the formation of laser-induced periodic surface structures upon irradiation of silicon by femtosecond-laser pulses N2 - The formation of nearly wavelength-sized laser-induced periodic surface structures (LIPSSs) on single-crystalline silicon upon irradiation with single or multiple femtosecond-laser pulses (pulse duration τ=130 fs and central wavelength λ=800 nm) in air is studied experimentally and theoretically. In our theoretical approach, we model the LIPSS formation by combining the generally accepted first-principles theory of Sipe and co-workers with a Drude model in order to account for transient intrapulse changes in the optical properties of the material due to the excitation of a dense electron-hole plasma. Our results are capable to explain quantitatively the spatial periods of the LIPSSs being somewhat smaller than the laser wavelength, their orientation perpendicular to the laser beam polarization, and their characteristic fluence dependence. Moreover, evidence is presented that surface plasmon polaritons play a dominant role during the initial stage of near-wavelength-sized periodic surface structures in femtosecond-laser irradiated silicon, and it is demonstrated that these LIPSSs can be formed in silicon upon irradiation by single femtosecond-laser pulses. KW - Ab initio calculations KW - Elemental semiconductors KW - High-speed optical techniques KW - Laser beam effects KW - Polaritons KW - Silicon KW - Solid-state plasma KW - Surface plasmons KW - Surface structure PY - 2009 DO - https://doi.org/10.1063/1.3261734 SN - 0021-8979 SN - 1089-7550 VL - 106 IS - 10 SP - 104910-1 - 104910-5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-20453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Pulse number dependence of laser-induced periodic surface structures for femtosecond laser irradiation of silicon N2 - The formation of nearly wavelength-sized laser-induced periodic surface structures (LIPSS) on single-crystalline silicon upon irradiation with single (N = 1) and multiple (N ≤ 1000) linearly polarized femtosecond (fs) laser pulses (pulse duration τ = 130 fs, central wavelength λ = 800 nm) in air is studied experimentally. Scanning electron microscopy (SEM) and optical microscopy are used for imaging of the ablated surface morphologies, both revealing LIPSS with periodicities close to the laser wavelength and an orientation always perpendicular to the polarization of the fs-laser beam. It is experimentally demonstrated that these LIPSS can be formed in silicon upon irradiation by single fs-laser pulses—a result that is additionally supported by a recent theoretical model. Two-dimensional Fourier transforms of the SEM images allow the detailed analysis of the distribution of the spatial frequencies of the LIPSS and indicate, at a fixed peak fluence, a monotonous decrease in their mean spatial period between ~770 nm (N = 1) and 560 nm (N = 1000). The characteristic decrease in the LIPSS period is caused by a feedback-mechanism acting upon excitation of surface plasmon polaritons at the rough silicon surface which is developing under the action of multiple pulses into a periodically corrugated surface. KW - Elemental semiconductors KW - Fourier transforms KW - Laser beam effects KW - Optical microscopy KW - Polarisation KW - Polaritons KW - Scanning electron microscopy KW - Silicon KW - Surface morphology KW - Surface plasmons PY - 2010 UR - http://jap.aip.org/resource/1/japiau/v108/i3/p034903_s1 DO - https://doi.org/10.1063/1.3456501 SN - 0021-8979 SN - 1089-7550 VL - 108 IS - 3 SP - 034903-1 - 034903-5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-21804 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beke, S. A1 - Sugioka, K. A1 - Midorikawa, K. A1 - Péter, Á. A1 - Nánai, L. A1 - Bonse, Jörn T1 - Characterization of the ablation of TeO2 crystals in air with femtosecond laser pulses N2 - Femtosecond (fs) laser pulse ablation (pulse duration of 150 fs, wavelength of 775 nm, repetition rate of 1 kHz) of single-crystalline TeO2 surfaces was performed in air using the direct focusing technique. The lateral and vertical dimensions of laser ablated craters as well as the laser damage thresholds were evaluated for different pulse numbers applied to the same spot. The joint observation using optical microscopy, atomic force microscopy and scanning electron microscopy revealed the surface morphology of the ablated craters and also showed that the ablation threshold depends significantly on the number of laser pulses applied to the same spot due to incubation effects. The incubation effects change the absorption processes involved in fs-laser ablation of the transparent material from multiphoton absorption to a single-photon absorption. These results are discussed on the basis of recent models of the interaction of fs-laser pulses with dielectrics. KW - Femtosecond laser ablation KW - Damage threshold KW - TeO2 KW - Dielectrics PY - 2010 DO - https://doi.org/10.1088/0022-3727/43/2/025401 SN - 0022-3727 SN - 1361-6463 VL - 43 IS - 2 SP - 025401-1 - 025401-6 PB - IOP Publ. CY - Bristol AN - OPUS4-20665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Probing the heat affected zone by chemical modifications in femtosecond pulse laser ablation of titanium nitride films in air N2 - A new approach is presented to quantify the so-called "heat affected zone" (HAZ) during femtosecond laser pulse processing. Ablation of titanium nitride (TiN) thin films (~3 μm thickness) by multiple femtosecond laser pulses (τ=130 fs, λ=800 nm) in air environment was studied by means of two different surface analytical methods both being sensitive to chemical alterations at the surface. Scanning Auger electron microscopy was applied for a visualization of the spatial distribution of specific elements (Ti, O) within the laser-modified areas. The chemical state of the irradiated surface was revealed by complementary x-ray photoelectron spectroscopy. Both methods were used for a depth-profiling chemical analysis (tracking the elements Ti, N, O, and C) using an Ar-ion beam for surface sputtering. In a narrow laser fluence range slightly below the ablation threshold of TiN significant superficial oxidation can be observed leading to the formation of substoichiometric TiO2-x. At fluences above the ablation threshold, an increased titanium concentration is observed within the entire ablation craters. Following upon sputter removal the elemental distribution into the depth of the nonablated material, the results allow an estimation of the heat-affected zone for femtosecond laser ablation in air environment. According to our analyses, the HAZ extends up to a few hundreds of nanometers into the nonablated material. KW - Femtosecond laser ablation KW - Heat affected zone KW - Titanium nitride KW - Scanning Auger electron microscopy KW - X-ray KW - Photoelektron spectroscopy PY - 2010 UR - http://link.aip.org/link/?JAP/107/054902 DO - https://doi.org/10.1063/1.3311552 SN - 0021-8979 SN - 1089-7550 VL - 107 IS - 5 SP - 054902-1 - 054902-5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-20949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beke, S. A1 - Sugioka, K. A1 - Midorikawa, K. A1 - Bonse, Jörn T1 - Near-IR femtosecond and VUV nanosecond laser processing of TeO2 crystals in air N2 - Near-IR femtosecond ( τ = 150 fs, λ = 775 nm, repetition rate 1 kHz) and VUV nanosecond (τ = 20 ns, λ = 157 nm, repetition rate 1 to 5 Hz) laser pulse ablation of single-crystalline TeO2 (c-TeO2, grown by the balance controlled Czochalski growth method) surfaces was performed in air using the direct focusing technique. The multi-method characterization using optical microscopy, atomic force microscopy and scanning electron microscopy revealed the surface morphology of the ablated craters. This allowed us to characterize precisely the lateral and vertical dimensions of the laser-ablated craters for different laser pulse energies and pulse numbers at each spot. Based on the obtained information, we quantitatively determined the ablation threshold fluence for the fs laser irradiation when different pulse numbers were applied to the same spot by using two independent extrapolation techniques. We found that in case of NIR femtosecond laser pulse irradiation, the ablation threshold significantly depends on the number of laser pulses applied to the same spot indicating that incubation effects play an important role in this material. In case of VUV ns laser pulses, the ablation rate is significantly higher due to the high photon energy and the predominantly linear absorption in the material. These results are discussed on the basis of recent models of the interaction of laser pulses with dielectrics. PY - 2010 DO - https://doi.org/10.1117/12.845074 SN - 0277-786X SN - 0038-7355 SN - 0361-0748 VL - 7584 SP - 758415-1 - 758415-10 PB - Soc. CY - Redondo Beach, Calif. [u.a.] AN - OPUS4-20912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Puerto, D. A1 - Siegel, J. A1 - Gawelda, W. A1 - Galvan-Sosa, M. A1 - Ehrentraut, L. A1 - Bonse, Jörn A1 - Solis, J. T1 - Dynamics of plasma formation, relaxation, and topography modification induced by femtosecond laser pulses in crystalline and amorphous dielectrics N2 - We have studied plasma formation and relaxation dynamics along with the corresponding topography modifications in fused silica and sapphire induced by single femtosecond laser pulses (800 nm and 120 fs). These materials, representative of high bandgap amorphous and crystalline dielectrics, respectively, require nonlinear mechanisms to absorb the laser light. The study employed a femtosecond time-resolved microscopy technique that allows obtaining reflectivity and transmission images of the material surface at well-defined temporal delays after the arrival of the pump pulse which excites the dielectric material. The transient evolution of the free-electron plasma formed can be followed by combining the time-resolved optical data with a Drude model to estimate transient electron densities and skin depths. The temporal evolution of the optical properties is very similar in both materials within the first few hundred picoseconds, including the formation of a high reflectivity ring at about 7 ps. In contrast, at longer delays (100 ps–20 ns) the behavior of both materials differs significantly, revealing a longer lasting ablation process in sapphire. Moreover, transient images of sapphire show a concentric ring pattern surrounding the ablation crater, which is not observed in fused silica. We attribute this phenomenon to optical diffraction at a transient elevation of the ejected molten material at the crater border. On the other hand, the final topography of the ablation crater is radically different for each material. While in fused silica a relatively smooth crater with two distinct regimes is observed, sapphire shows much steeper crater walls, surrounded by a weak depression along with cracks in the material surface. These differences are explained in terms of the most relevant thermal and mechanical properties of the material. Despite these differences the maximum crater depth is comparable in both material at the highest fluences used (16J/cm2). The evolution of the crater depth as a function of fluence can be described taking into account the individual bandgap of each material. KW - Femtosecond laser ablation KW - Plasma formation KW - Time-resolved microscopy KW - Dielectrics KW - Fused silica KW - Sapphire KW - Scanning force microscopy KW - Reflectivity measurements KW - Transmission measurements KW - Drude model PY - 2010 DO - https://doi.org/10.1364/JOSAB.27.001065 SN - 0740-3224 SN - 1520-8540 VL - 27 IS - 5 SP - 1065 EP - 1076 PB - Optical Society of America CY - Washington, DC AN - OPUS4-21167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schultz, C. A1 - Schüle, M. A1 - Stelmaszczyk, K. A1 - Bonse, Jörn A1 - Witteck, R. A1 - Weizman, M. A1 - Rhein, H. A1 - Rau, B. A1 - Schlatmann, R. A1 - Quaschning, V. A1 - Stegemann, B. A1 - Fink, F. T1 - Film side laser patterning of molybdenum thin films sputter-deposited onto glass N2 - Serial interconnection of CIGSe thin film solar modules involves typically glass-side laser patterning of the molybdenum layer (P1 scribe). In this paper we present a working principle of P1 film side patterning. The investigated samples were sputter-deposited onto soda-lime glass substrates. For understanding the fundamental ablation behavior, two kinds of layer systems were studied: on the one hand monolayer systems which are compressively stressed and on the other hand bilayer systems, consisting of a tensile stressed layer on the substrate and a second layer on top. The film-side ablation process was studied using a nanosecond as well as a picosecond laser source. The influence of intrinsic stress was studied by XRD. Time resolved spectroscopy reveals the formation of plasma as important driving mechanism for ablation. It is shown that by proper adaption of the sputter conditions high-quality P1 film side patterning is achieved. T2 - 27th European photovoltaic solar energy conference and exhibition CY - Frankfurt, Germany DA - 24.09.2012 KW - Laser processing KW - Molybdenum KW - Strain KW - Ablation KW - Sputter deposition KW - Cu(InGa)Se2 PY - 2012 SN - 3-936338-28-0 DO - https://doi.org/10.4229/27thEUPVSEC2012-3CV.1.6 SP - 2266 EP - 2272 AN - OPUS4-27208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Beke, S. A1 - Sugioka, K. A1 - Midorikawa, K. A1 - Bonse, Jörn ED - Hemsworth, E.J. T1 - Nanosecond and femtosecond laser ablation of TeO2 crystals: surface characterization and plasma analysis N2 - Near-IR femtosecond (fs) (pulse duration = 150 fs, wavelength = 775 um, Repetition rate 1 kHz) and VUV nanosecond (ns) (pulse duration = 20 ns, wavelength = 157 nm, repetition rate 1 to 5 Hz) laser pulse ablation of single-crystalline TeO? (c-Te02) surfaces was performed in air using the direct focusing technique. A multi-method characterization using optical microscopy, atomic force microscopy and scanning electron microscopy revealed the surface morphology of the ablated craters. This allowed us at each irradiation site to characterize precisely the lateral and vertical dimensions of the laser-ablated craters for different laser pulse energies and number of laser pulses per spot. Based on the obtained information, we quantitatively determined the Ablation threshold fluence for the fs laser irradiation when different pulse numbers were applied to the same spot using two independent extrapolation techniques. We found that in the case of NIR fs laser pulse irradiation, the ablation threshold significantly depends on the number of laser pulses applied to the same spot indicating that incubation effects play an important role in this material. In the case of VUV ns laser pulses, the ablation rate is significantly higher due to the high photon energy and the predominantly linear absorption in the material. These results are discussed on the basis of recent models of the interaction of laser pulses with dielectrics. In the second part of this chapter, we use timeof-flight mass spectrometry (TOFMS) to analyze the elemental composltion of the ablation products generated upon laser irradiation of c-Te02 with single fs- (pulse duration ~ 200 fs, wavelength 398 nm) and ns-pulses (pulse duration 4 ns, wavelength 355 nm). Due to the three Order of magnitude different peak intensities of the ns- and fs laser pulses, significant differences were observed regarding the laser-induced species in the plasma plume. Positive singly, doubly and triply charged Te ions (Te+, Te2+, Te3+) in the form of many different isotopes were observed in case of both irradiations. In the case of the ns-laser ablation, the TeO+ formation was negligible compared to the fs case and there was no Te trimer (Te3+) formation observed. It was found that the amplitude of Te ion Signals strongly depends on the applied laser pulse energy. Singly charged Oxygen ions (0+) are always present as a byproduct in both kinds of laser ablation. KW - Femtosecond laser ablation KW - Nanosecond laser ablation KW - Damage threshold KW - TeO2 KW - Dielectrics KW - Time-of-flight mass spectrometry (TOF-MS) PY - 2011 SN - 978-1-61324-851-5 N1 - Serientitel: Physics Research and Technology – Series title: Physics Research and Technology IS - Chapter 4 SP - 77 EP - 96 PB - Nova Science Publishers, Inc. AN - OPUS4-25465 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 - Formation of laser-induced periodic surface structures on fused silica upon two-color double-pulse irradiation 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 - Bonse, Jörn A1 - Mann, Guido A1 - Krüger, Jörg A1 - Marcinkowski, M. A1 - Eberstein, M. T1 - Femtosecond laser-induced removal of silicon nitride layers from doped and textured silicon wafers used in photovoltaics N2 - The removal of a 75- to 90-nm-thick passivating silicon nitride antireflection coating from standard textured multicrystalline silicon photovoltaic wafers with a typical diffused 90-Ω/sq-emitter upon irradiation with near-infrared femtosecond laser pulses (790 nm central wavelength, 30 fs pulse duration) is studied experimentally. The laser irradiation areas are subsequently characterized by complementary optical microscopy, scanning electron microscopy and depth profiling chemical analyses using secondary ion mass spectrometry. The results clarify the thin-film femtosecond laser ablation scenario and outline the process windows for selective antireflection coating removal. KW - Photovoltaics KW - Solar cell KW - Laser processing KW - FS-laser ablation KW - Silicon nitride PY - 2013 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 - VIDEO A1 - Schwibbert, Karin A1 - Richter, Anja A1 - Bonse, Jörn T1 - BioCombs4Nanofibers: From nanofibers over spiders to bacteria N2 - This 6 minute long MP4-video presents some key results of the European research project "BioCombs4Nanofibers" to the broader public. Inspired by nature, some concepts of certain types of spiders are transferred to technology in order to develop bacteria-repellent surfaces through laser surface nanostructuring. Funding notice: This study was funded by the European Union's research and innovation program under the FET Open grant agreement No. 862016 (BioCombs4Nanofibers, http://biocombs4nanofibers.eu). KW - Antiadhesive surfaces KW - Laser-induced periodic surface structures (LIPSS) KW - Cribellate spiders KW - Bacterial adhesion tests KW - Bacteria-repellent surfaces PY - 2022 UR - https://download.jku.at/org/7kM/xyU/BioCombs4Nanofibers/D5.6_video%20for%20the%20broader%20public_23.03.2022.mp4 UR - https://www.jku.at/en/biocombs4nanofibers/dissemination/ DO - https://doi.org/10.26272/opus4-54939 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-54939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Mezera, Marek A1 - Wasmuth, Karsten A1 - Richter, Anja A1 - Schwibbert, Karin A1 - Krüger, Jörg A1 - Müller, F. A. A1 - Gräf, S. T1 - A brief survey on open questions about laser-induced periodic surface structures N2 - The processing of laser-induced periodic surface structures (LIPSS) represents a simple and robust way for the nanostructuring of solids that allows creating a wide range of surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m2/min level, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation aims to identify some unsolved scientific problems related to LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry. T2 - E-MRS Spring Meeting 2022 CY - Online meeting DA - 30.05.2022 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Industrial applications KW - Biofilm growth PY - 2022 AN - OPUS4-54929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Mirabella, Francesca A1 - Mezera, Marek A1 - Weise, Matthias A1 - Sahre, Mario A1 - Wasmuth, Karsten A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Chemical and structural changes at the surface of titanium materials upon irradiation with near-infrared ultrashort laser pulses N2 - Due to its large strength-to-weight ratio and excellent biocompatibility, titanium materials are of paramount importance for medical applications, e.g. as implant material for protheses. In this work, the evolution of various types of laser-induced micro- and nanostructures emerging on titanium or titanium alloys upon irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment is studied for various laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz). The morphologies of the processed surfaces were systematically characterized by optical and scanning electron microscopy (OM, SEM). Complementary white-light interference microscopy (WLIM) revealed the corresponding surface topographies. Chemical and structural changes were analysed through depth-profiling time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray diffraction (XRD) analyses. The results point towards a remarkable influence of the laser processing parameters on the surface topography, while simultaneously altering the near-surface chemistry via laser-induced oxidation effects. Consequences for medical applications are outlined. T2 - E-MRS Spring Meeting 2022 CY - Online meeting DA - 30.05.2022 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - ToF-SIMS KW - Chemical analysis KW - Titanium PY - 2022 AN - OPUS4-54931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Porta-Velilla, L. A1 - Turan, N. A1 - Cubero, Á. A1 - Shao, W. A1 - Li, H. A1 - de la Fuente, G.F. A1 - Martínez, E. A1 - Larrea, Á. A1 - Castro, M. A1 - Koralay, H. A1 - Çavdar, Ş. A1 - Bonse, Jörn A1 - Angurel, L.A. T1 - Highly Regular Hexagonally-Arranged Nanostructures on Ni-W Alloy Tapes upon Irradiation with Ultrashort UV Laser Pulses N2 - Nickel tungsten alloy tapes (Ni—5 at% W, 10 mm wide, 80 µm thick, biaxially textured) used in second-generation high temperature superconductor (2G-HTS) technology were laser-processed in air with ultraviolet ps-laser pulses (355 nm wavelength, 300 ps pulse duration, 250–800 kHz pulse repetition frequency). By employing optimized surface scan-processing strategies, various laser-generated periodic surface structures were generated on the tapes. Particularly, distinct surface microstructures and nanostructures were formed. These included sub-wavelength-sized highly-regular hexagonally-arranged nano-protrusions, wavelength-sized line-grating-like laser-induced periodic surface structures (LIPSS, ripples), and larger irregular pyramidal microstructures. The induced surface morphology was characterized in depth by electron-based techniques, including scanning electron microscopy (SEM), electron back scatter diffraction (EBSD), cross-sectional transmission electron microscopy (STEM/TEM) and energy dispersive X-ray spectrometry (EDS). The in-depth EBSD crystallographic analyses indicated a significant impact of the material initial grain orientation on the type of surface nanostructure and microstructure formed upon laser irradiation. Special emphasis was laid on high-resolution material analysis of the hexagonally-arranged nano-protrusions. Their formation mechanism is discussed on the basis of the interplay between electromagnetic scattering effects followed by hydrodynamic matter re-organization after the laser exposure. The temperature stability of the hexagonally-arranged nano-protrusion was explored in post-irradiation thermal annealing experiments, in order to qualify their suitability in 2G-HTS fabrication technology with initial steps deposition temperatures in the range of 773–873 K. KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser processing KW - Hexagonally-arranged nano-protrusions KW - Second-generation high temperature superconductor technology KW - Electron microscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552551 DO - https://doi.org/10.3390/nano12142380 SN - 2079-4991 VL - 12 IS - 14 SP - 1 EP - 23 PB - MDPI CY - Basel, Switzerland AN - OPUS4-55255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -