TY - GEN A1 - Varlamova, Olga A1 - Costache, Florenta Adriana A1 - Reif, Jürgen A1 - Bestehorn, Michael T1 - Self-organized pattern formation upon femtosecond laser ablation by circularly polarized light T2 - Applied Surface Science KW - femtosecond laser ablation KW - nanostructures KW - self-organization Y1 - 2006 SN - 0169-4332 VL - 252 IS - 13 SP - 4702 EP - 4706 ER - TY - GEN A1 - Reif, Jürgen A1 - Varlamova, Olga A1 - Varlamov, Sergej A1 - Bestehorn, Michael T1 - The role of asymmetric excitation in self-organized nanostructure formation upon femtosecond laser ablation T2 - Applied Physics / A Y1 - 2011 SN - 1432-0630 VL - 104 IS - 3 SP - 969 EP - 973 ER - TY - GEN A1 - Varlamova, Olga A1 - Reif, Jürgen A1 - Varlamov, Sergej A1 - Bestehorn, Michael T1 - The laser polarization as control parameter in the formation of laser-induced periodic surface structures: Comparison of numerical and experimental results T2 - Applied Surface Science Y1 - 2011 SN - 0169-4332 VL - 257 IS - 12 SP - 5465 EP - 5469 ER - TY - GEN A1 - Varlamova, Olga A1 - Reif, Jürgen A1 - Varlamov, Sergej A1 - Bestehorn, Michael T1 - Modeling of the Laser Polarization as Control Parameter in Self-Organized Surface Pattern T2 - Journal of Nanoscience and Nanotechnology Y1 - 2011 SN - 1533-4880 VL - 11 IS - 10 SP - 9274 EP - 9281 ER - TY - GEN A1 - Reif, Jürgen A1 - Varlamova, Olga A1 - Uhlig, Sebastian A1 - Varlamov, Sergej A1 - Bestehorn, Michael T1 - On the physics of self-organized nanostructure formation upon femtosecond laser ablation T2 - Applied Physics A N2 - We present new results on femtosecond LIPSS on silicon, fostering the dynamic model of self-organized structure formation. The first set of experiments demonstrates LIPSS formation by irradiation with a femtosecond white light continuum. The ripples are, as usual, perpendicular to the light polarization with a fluence-dependent wavelength between 500 and 700 nm. At higher dose (fluence × number of shots), the LIPSS turn to much coarser structures. The second set of experiments displays the dose dependence of pattern evolution at about threshold fluence. In contrast to the general case of multi-pulse LIPSS, where a strong dependence of the structures on the laser polarization is observed, single-shot exposition of silicon at about the ablation threshold results in a concentric pattern of very regular sub-wavelength ripples following the oval shape of the irradiated spot, without any reference to the laser polarization. When increasing the number of pulses, the usual, typical ripples develop and then coalesce into broader perpendicular structures, interlaced with remnants of the first, finer ripples. Y1 - 2014 UR - http://link.springer.com/article/10.1007/s00339-014-8339-x U6 - https://doi.org/10.1007/s00339-014-8339-x SN - 0947-8396 SN - 1432-0630 VL - 117 IS - 1 SP - 179 EP - 184 ER - TY - GEN A1 - Razi, Sepehr A1 - Varlamova, Olga A1 - Reif, Jürgen A1 - Bestehorn, Michael A1 - Varlamov, Sergej A1 - Mollabashi, Mahmoud A1 - Madanipour, Khosro A1 - Ratzke, Markus T1 - Birth of periodic Micro/Nano structures on 316L stainless steel surface following femtosecond laser irradiation; single and multi scanning study T2 - Optics & Laser Technology N2 - Formation of coherent laser induced periodic surface structures (LIPSS) on stainless steel type 316L by 100 fs laser pulses at 800 nm wavelength is investigated. Specifically focusing on the large area treatment, effect of the irradiation dose (fluence × pulse number) on the uniformity of the morphology, orientation of the ripples respect to the laser polarization and their periodicity is studied systematically. Controlling the pulse number via varying the scanning speed, the difference between irradiating one particular dose in single scan with its irradiation in separate steps is inspected. Results clearly point out that not only the irradiation dose but also the irradiation way and the time delay between the pulse trains might have a significant effect on the final outcomes. It is discussed in detail that the experimental observations are supporting the model of self-organized structure formation due to irradiation induced instability. KW - Laser surface processing KW - Laser induced periodic surface structures KW - Steel Y1 - 2018 UR - https://www.sciencedirect.com/science/article/pii/S0030399217310320#! U6 - https://doi.org/10.1016/j.optlastec.2018.02.001 SN - 0030-3992 SN - 0308-4280 VL - 104 SP - 8 EP - 16 ER - TY - GEN A1 - Borcia, Rodica A1 - Borcia, Ion-Dan A1 - Bestehorn, Michael A1 - Varlamova, Olga A1 - Hoefner, Kevin A1 - Reif, Jürgen T1 - Drop Behavior Influenced by the Correlation Length on Noisy Surfaces T2 - Langmuir Y1 - 2019 U6 - https://doi.org/10.1021/acs.langmuir.8b03878 VL - 35 SP - 928 EP - 934 ER - TY - GEN A1 - Varlamova, Olga A1 - Reif, Jürgen A1 - Stolz, Michael A1 - Borcia, Rodica A1 - Borcia, Ion-Dan A1 - Bestehorn, Michael T1 - Wetting properties of LIPSS structured silicon surfaces T2 - The European Physical Journal B N2 - The controlled dynamics of liquid drops via generation of specific wetting states on a solid surface is of great interests both in the fundamental and applied sciences. Considering that the wettability is strongly dependent on the surface topography and surface roughness, we investigate – through experiments and theory – the effect of laser-induced periodic surface structures (LIPSS) generated on silicon (100) targets as a control parameter of wetting properties. To obtain structured silicon surfaces with different morphological features, we patterned the surface by irradiation with femtosecond pulses from an amplified Ti:Sapphire laser system (790 nm/100 fs/1 kHz) at a fluence in the range of 0.4–1.2 J/cm2 on a spot with a diameter about of 100 μm. Variation of the applied irradiation dose results in surface modifications with the roughness about of a few tens of nanometers are ranging from regular LIPSS patterns with the lateral period of about 500–700 nm to complex agglomerations of 3-D microstructures with several-μm feature size. The theoretical study on the correlation of wetting properties with the surface topography has been performed within a phase field model. We found an excellent agreement of numerical results with experiments. Y1 - 2019 U6 - https://doi.org/10.1140/epjb/e2019-90672-2 SN - 1434-6036 SN - 1434-6028 VL - 92 IS - 5 ER -