Filtern
Erscheinungsjahr
Dokumenttyp
- Vortrag (68)
- Posterpräsentation (31)
- Beitrag zu einem Tagungsband (21)
- Zeitschriftenartikel (14)
- Buchkapitel (10)
- Beitrag zu einem Sammelband (4)
- Monografie (1)
- Corrigendum (1)
- Video (1)
Referierte Publikation
- nein (151) (entfernen)
Schlagworte
- Laser-induced periodic surface structures (LIPSS) (35)
- Surface functionalization (21)
- Femtosecond laser (17)
- Femtosecond laser ablation (14)
- Laser processing (13)
- Applications (9)
- Laser-induced periodic surface structures, LIPSS (9)
- Laser ablation (7)
- Microstructures (6)
- Nanostructures (6)
- Oxidation (6)
- Friction (5)
- Tribology (5)
- Wear (5)
- Ablation (4)
- Electromagnetic scattering (4)
- Capillary waves (3)
- Femtosecond laser processing (3)
- Hard X-ray photoelectron spectroscopy (HAXPES) (3)
- Laser-induced X-ray emission (3)
- Oberflächenfunktionalisierung (3)
- Ultrafast laser processing (3)
- Wetting (3)
- Atomic force microscopy (2)
- Chalcopyrite (2)
- Cu(InGa)Se2 (2)
- Damage threshold (2)
- Dielectrics (2)
- Doping (2)
- Femtosecond (2)
- Free electron laser (2)
- Incubation (2)
- Indium phosphide (2)
- Industrial applications (2)
- LIPSS (2)
- Laser-Materialbearbeitung (2)
- Laser-induced periodic surface structures (2)
- Light concentration (2)
- Micro solar cells (2)
- Nanosecond laser ablation (2)
- Nanostrukturen (2)
- Radiation protection (2)
- Selective emitter (2)
- Silicon (2)
- Steel (2)
- Ti6Al4V alloy (2)
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) (2)
- Time-resolved scattering (2)
- Titanium alloy (2)
- 100Cr6 (1)
- 532 nm wavelength (1)
- Absorber optimization (1)
- Additive (1)
- Additives (1)
- Anodization (1)
- Antiadhesive surfaces (1)
- Antibakterielle Oberflächen (1)
- Antimicrobial (1)
- Auger electron spectroscopy (1)
- Bacteria (1)
- Bacteria-repellent surfaces (1)
- Bacterial adhesion tests (1)
- Bessel-Strahlen (1)
- Biofilm growth (1)
- Biofilme (1)
- Biofilms (1)
- Bone screws (1)
- CIGS (1)
- Carrier excitation (1)
- Carrier plasmas (1)
- Cell adhesion (1)
- Cell-repellent surfaces (1)
- Chalkopyrite (1)
- Chemical analyses (1)
- Chemical analysis (1)
- Copper indium gallium diselenide (CIGSe) (1)
- Cribellate spiders (1)
- CuInSe2 (1)
- Double-pulse (1)
- Dünnschichtsolarzellen (1)
- Electrical properties (1)
- Electrochemical treatment (1)
- Electromagnetic radiation (1)
- Femtosecond laser irradiation (1)
- Femtosecond laser-processing (1)
- Femtosecond pulse laser (1)
- Femtosekunden-Laserablation (1)
- Femtosekundenlaser (1)
- Finite-difference time-domain calculations (1)
- Fluid transport (1)
- Force distance curve (1)
- Free electron laser (FEL) (1)
- Glasses (1)
- Glow-discharge optical emission spectroscopy (1)
- Hydrodynamics (1)
- Implant material (1)
- Interferometer (1)
- Ionic liquid (1)
- Isotopes (1)
- LIFT (1)
- Laser induced periodic surface structures (LIPSS) (1)
- Laser material processing (1)
- Laser materials processing (1)
- Laser nanostructuring (1)
- Laser scribing (1)
- Laser technology (1)
- Laser-induced Periodic Surface Structures (LIPSS) (1)
- Laser-induced amorphization (1)
- Laser-induced forward transfer (LIFT) (1)
- Laser-induced micro- and nanostructures (1)
- Laser-induced periodic surface strcutures (LIPSS) (1)
- Laser-induced periodic surface strcutures, LIPSS (1)
- Laser-induzierte periodische Oberflächen-Nanostrukturen (1)
- Laser-induzierte periodische Oberflächenstrukturen (1)
- Laserschutz (1)
- Laserstrukturierung (1)
- Lizard (1)
- Lizards (1)
- Lubrication (1)
- Materialbearbeitung (1)
- Matter reorganization (1)
- Medical implants (1)
- Metals (1)
- Micro solar cell (1)
- Micromachining (1)
- Microstructure (1)
- Mikrostrukturen (1)
- Modelling (1)
- Molybdenum (1)
- Multicrystalline silicon (1)
- Multiphoton absorption (1)
- Nanometrology (1)
- Nanosecond pulses (1)
- Nanostrcutures (1)
- Native oxide layer (1)
- Nonlinear lithography (1)
- Oberflächenmodifikation (1)
- Optical properties (1)
- Optical scattering (1)
- Optics at surfaces (1)
- PAG (1)
- Pacemaker (1)
- Photovoltaik (1)
- Polymer (1)
- Pulse shaping (1)
- Pump-probe (1)
- Pump-probe experiments (1)
- Quantitative phase-contrast microscopy (1)
- Quarzglas (1)
- Reactive oxygen species (1)
- Refractive index engineering (1)
- Reibung (1)
- Reibungsreduktion (1)
- Ripples (1)
- Röntgenemission (1)
- Saphir (1)
- Scanning electron microscopy (1)
- Scanning/atomic force microscopy (SFM/AFM) (1)
- Second harmonic generation (SHG) (1)
- Secondary hazard (1)
- Sekundärstrahlung (1)
- Self-organization (1)
- Semiconductor (1)
- Semiconductors (1)
- Silicon solar cell (1)
- Simulation (1)
- Spatial light interference microscopy (1)
- Spectroscopic imaging ellipsometry (1)
- Sputter deposition (1)
- Stiffness (1)
- Strain (1)
- Surface engineering (1)
- Surface plasmon polaritons (1)
- Surface structures (1)
- TeO2 (1)
- Tellurium dioxide crystals (1)
- Theoretical modelling (1)
- Thin-film solar cells (1)
- TiAl64V (1)
- Time-of-flight mass spectrometry (TOF-MS) (1)
- Time-of-flight mass spectroscopy (1)
- Time-offlight secondary ion mass spectrometry (ToF-SIMS) (1)
- Time-resolved analysis (1)
- Time-resolved coherent XUV scattering (1)
- Time-resolved coherent scattering (1)
- Titanium (1)
- Titanium alloys (1)
- Titanium nitride (1)
- ToF-SIMS (1)
- Transmission electron microscopy (1)
- Tribologie (1)
- Ultra-short pulse laser processing (1)
- Ultrafast laser excitation (1)
- Ultrafast phenomena (1)
- Ultrafast scattering (1)
- Ultrakurze Laserpulse (1)
- Ultrakurzpuls-Laser (1)
- Ultrakurzpuls-Laserbearbeitung (1)
- Ultrashort (1)
- Ultrashort laser material interaction (1)
- Ultrashort laser processing (1)
- Ultrashort laser pulses (1)
- Ultrashort pulse laser processing (1)
- VUV nanosecond laser ablation (1)
- Verschleiß (1)
- Verschleißreduktion (1)
- X-ray (1)
- XUV scattering (1)
- a-Si/my-Si (1)
Organisationseinheit der BAM
- 6 Materialchemie (59)
- 6.2 Material- und Oberflächentechnologien (59)
- 9 Komponentensicherheit (11)
- 9.5 Tribologie und Verschleißschutz (11)
- 6.1 Oberflächen- und Dünnschichtanalyse (8)
- 4 Material und Umwelt (5)
- 4.1 Biologische Materialschädigung und Referenzorganismen (5)
- 6.6 Physik und chemische Analytik der Polymere (1)
Paper des Monats
- ja (1)
Lasermaterialbearbeitung ist eine sich schnell entwickelnde Technologie, um eine Vielzahl von Oberflächenfunktionalitäten auf Basis optischer, mechanischer oder chemischer Eigenschaften zu realisieren. Die Verwendung ultrakurzer Laserimpulse mit Dauern im Femtosekundenbereich ermöglicht dabei neben einer herausragenden Bearbeitungs-präzision auch die selbstorganisierte Erzeugung verschiedener charakteristischer Ober-flächenstrukturen mit Größenskalen im Mikrometer- bis hinunter in den sub-100-nm-Bereich, z.B. sogenannte Ripples („Laser-Induced Periodic Surface Structures“, LIPSS), Grooves, oder Spikes.
In dem Vortrag wird ein Überblick über die in den vergangenen Jahren in Zusammenarbeit mit dem BAM Fachbereich 6.3 durchgeführten tribologischen Experimente gegeben. Besonderes Augenmerk liegt dabei auf den tribologischen Eigenschaften (Reibung und Verschleiß) der unterschiedlichen Femtosekunden-Laser-generierten Oberflächen-morphologien auf gängigen Metallen (z.B. Stahl, Titan). Einflüsse durch die Veränderungen der Härte des Werkstoffs infolge Laser-induzierter Oxidation, der Dicke und Struktur der Oxidschicht, und die Wirksamkeit unterschiedlicher Schmiermittel (z.B. additiviertes Motoröl) werden diskutiert.
Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range.
During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animal integuments, the tailoring of surface colonization by bacterial biofilms, the advancement of medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces.
This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures 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, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.
Irradiation of solid surfaces with intense ultrashort laser pulses represents a unique way of depositing energy into materials. It allows to realize states of extreme electronic excitation and/or very high temperature and pressure and to drive materials close to and beyond fundamental stability limits. As a consequence, structural changes and phase transitions often occur along unusual pathways and under strongly nonequilibrium conditions. Due to the inherent multiscale nature — both temporally and spatially—of these irreversible processes, their direct experimental observation requires techniques that combine high temporal resolution with the appropriate spatial resolution and the capability to obtain good quality data on a single pulse/event basis. In this respect, fourth-generation light sources, namely, short wavelength and short pulse free electron lasers (FELs), are offering new and fascinating possibilities. As an example, this talk will discuss the results of scattering experiments carried out at the FLASH free electron laser at DESY (Hamburg, Germany), which allowed us to resolve laser-induced structure formation at surfaces on the nanometer to submicron length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution. The current status and future perspectives in this field via exploiting the unique possibilities of these 4th-generation light sources will be discussed.
Chemical effects during the formation of femtosecond laser-induced periodic surface structures
(2019)
The processing of laser-induced periodic surface structures (LIPSS, ripples) on metals and semiconductors in ambient air is usually accompanied by superficial oxidation effects – a fact that is widely neglected in the current literature. In this contribution, chemical, structural, and mechanical alterations in the formation of femtosecond LIPSS are characterized by a variety of surface analytical techniques, including energy dispersive X-ray analyses (EDX), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy (µ-RS), and depth-profiling Auger electron microscopy (AEM). Alternative routes of electrochemical and thermal oxidation allow to qualify the relevance of superficial oxidation effects on the tribological performance in oil lubricated reciprocating sliding tribological tests (RSTT). It is revealed that the fs-laser processing of near-wavelength sized LIPSS on metals leads to the formation of a few hundreds of nanometers thick graded oxide layers, consisting mainly of amorphous oxides. Regardless of reduced hardness and limited thickness, this nanostructured surface layer efficiently prevents a direct metal-to-metal contact in the RSTT and may also act as an anchor layer for specific wear-reducing additives contained in the used engine oil.
Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation.
From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc.
This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
Fourth generation light sources, namely short wavelength, short pulse free electron lasers (FELs) are offering new and fascinating possibilities to resolve laser-induced structure formation at surfaces on the sub-micrometer to nanometer length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution. This unique spatio-temporal resolution allows to reveal early signatures of coherent/plasmonic electromagnetic scattering effects followed by the excitation of hydrodynamic capillary waves – providing new insights to the above-mentioned debate.
Finally, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. While the currently available laser and scanner technology already allows large area surface processing with rates at the m2/min level, industrial applications of LIPSS are sometimes limited 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. Strategies for overcoming such limitations are outlined.
Der Vortrag gibt einen Überblick über die Erzeugung und Charakterisierung anisotroper Nanostrukturen mittels ultrakurzgepulster Laserstrahlung. Besonderes Augenmerk liegt dabei auf dem Phänomen der sogenannten Laser-induzierten periodischen Oberflächen-Nanostrukturen auf dielektrischen Werkstoffen und ihrer zeitlichen Dynamik. Weitere Beispiele von Volumen-Nanostrukturen aus der Literatur werden diskutiert.
Laser-induced periodic surface structures (LIPSS) have gained remarkable attention as they represent a universal phenomenon that is often accompanying laser-processing. Such LIPSS enable a plethora of different surface functionalizations for applications in the fields of optics, fluidics, tribology, or medicine. Due to the inherent multiscale nature of processes involved in LIPSS formation, their in-situ observation requires experimental techniques that combine high temporal resolution with the appropriate spatial resolution. In this respect fourth generation light sources, namely short wavelength, short pulse free electron lasers (FELs) are offering new and fascinating possibilities. This work contribution will discuss the results of scattering experiments carried at the FLASH free electron laser at DESY (Hamburg, Germany), which allowed us to resolve laser-induced structure formation at surfaces on the nm to sub-µm length scale and in temporal regimes ranging from ps to several ns with sub-ps resolution. A ps-optical pump / fs-XUV scattering probe scheme was employed to 100 nm thick laser-excited silicon films, while recording snapshots of the transmitted XUV scattering patterns at various delay times after the laser pulse impact. On timescales ranging from hundred ps until several ns almost quantitative agreement was observed between certain features of the recorded scattering patterns and predictions of the first-principles theory of J.E. Sipe and coworkers. Other scattering features appearing with a delay of ~100 ps and lasting for ~1 ns are attributed to capillary surface waves being excited at the laser-melted film material while ablation proceeds. Our superior spatio-temporal resolution experiments allow to uniquely reveal and distinguish early signatures of coherent/plasmonic electromagnetic scattering effects, separately followed by hydrodynamic matter reorganization.
Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the picosecond to femtosecond range. During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical or chemical properties. In this contribution current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting, the mimicry of the natural texture of animal integuments, the tailoring of surface colonization by bacterial biofilms, and the improvement of the tribological performance of nanostructured metal surfaces.
The wetting behavior of material surfaces can be controlled by surface structures. We functionalized case-hardened alloyed carbon steel to modify the wetting behavior using ultrashort laser pulses (fs- to ps-range). The laser processing was performed by scanning the laser beam across the surface of initially polished flat sample material. An experimental study of the laser processing parameters (peak fluence, scan velocity, line overlap) rendered an assignment of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, grooves, micro cones, etc.) possible. Analyzing the surface using optical as well as scanning electron microscopy allowed the identification of morphologies providing the optimum similarity to the natural skin of non-moisture havesting lizards. For mimicking skin structures of moisture-harvesting lizards, additionally a two-step laser processing strategy was established for realizing hierarchical microstructures. In this approach, micrometer-scaled capillaries (step 1) were superimposed by a laser-generated regular array of small dimples (step 2). Optical focus variation imaging measurements finally revealed the three dimensional topography of the laser processed surfaces derived from lizard skin structures. The functionality of these surfaces was analyzed in view of wetting and directional fluid transport properties. The results suggest possible applications of the laser-structured surfaces.