@article{RungRexhepiBischoffetal.2013, author = {Rung, Stefan and Rexhepi, Mal and Bischoff, Christian and Hellmann, Ralf}, title = {Laserscribing of thin films using top-hat laser beam profiles}, series = {Journal of Laser Micro/Nanoengineering}, volume = {8}, journal = {Journal of Laser Micro/Nanoengineering}, number = {3}, pages = {309 -- 314}, year = {2013}, subject = {D{\"u}nne Schicht}, language = {en} } @article{BischoffRungHellmann2012, author = {Bischoff, Christian and Rung, Stefan and Hellmann, Ralf}, title = {Efficient micromachining of thin film layers with nanosecond lasers - beam shaping optics improve process quality and enhance throughput}, series = {Laser Technik Journal}, volume = {9}, journal = {Laser Technik Journal}, number = {5}, pages = {15 -- 20}, year = {2012}, subject = {Laser}, language = {en} } @article{RischHellmann2011, author = {Risch, Anna and Hellmann, Ralf}, title = {Laser Scribing of Gallium Doped Zinc Oxide Thin Films using Picosecond Laser}, series = {Applied Surface Science}, volume = {258}, journal = {Applied Surface Science}, number = {5}, pages = {1849 -- 1853}, year = {2011}, subject = {Zinkoxid}, language = {en} } @article{HeilmannHellmannSeidl2011, author = {Heilmann, Eva-Maria and Hellmann, Ralf and Seidl, Albrecht}, title = {Water Jet Guided Laser Cutting of Silicon Thin Films Using 515nm Disc Laser}, series = {Journal of Laser Micro/Nanoengineering}, volume = {6}, journal = {Journal of Laser Micro/Nanoengineering}, number = {2}, pages = {168}, year = {2011}, subject = {Laserschneiden}, language = {en} } @article{RischHellmann2011, author = {Risch, Anna and Hellmann, Ralf}, title = {Picosecond Laser Patterning of ITO Thin Films}, series = {Physics Procedia 12-1, Elsevier Properties S.A}, journal = {Physics Procedia 12-1, Elsevier Properties S.A}, number = {12}, pages = {133 -- 140}, year = {2011}, subject = {Laserbearbeitung}, language = {en} } @inproceedings{RischHellmann2011, author = {Risch, Anna and Hellmann, Ralf}, title = {Laser induced modification of GZO thin film}, series = {Proceeding XXV microCAD, International scientific conference, 2011, Section K: Material science/Material processing technologies}, booktitle = {Proceeding XXV microCAD, International scientific conference, 2011, Section K: Material science/Material processing technologies}, pages = {69 -- 74}, year = {2011}, subject = {Laser}, language = {en} } @article{RungBarthHellmann2014, author = {Rung, Stefan and Barth, Johannes and Hellmann, Ralf}, title = {Characterization of Laser Beam Shaping Optics Based on Their Ablation Geometry of Thin Films}, series = {Micromachines}, volume = {5}, journal = {Micromachines}, number = {4}, pages = {943 -- 953}, year = {2014}, abstract = {Thin film ablation with pulsed nanosecond lasers can benefit from the use of beam shaping optics to transform the Gaussian beam profile with a circular footprint into a Top-Hat beam profile with a rectangular footprint. In general, the quality of the transformed beam profile depends strongly on the beam alignment of the entire laser system. In particular, the adjustment of the beam shaping element is of upmost importance. For an appropriate alignment of the beam shaper, it is generally necessary to observe the intensity distribution near the focal position of the applied focusing optics. Systems with a low numerical aperture (NA) can commonly be qualified by means of laser beam profilers, such as a charge-coupled device (CCD) camera. However, laser systems for micromachining typically employ focus lenses with a high NA, which generate focal spot sizes of only several microns in diameter. This turns out to be a challenge for common beam profiling measurement systems and complicates the adjustment of the beam shaper strongly. In this contribution, we evaluate the quality of a Top-Hat beam profiling element and its alignment in the working area based on the ablated geometry of single pulse ablation of thin transparent conductive oxides. To determine the best achievable adjustment, we develop a quality index for rectangular laser ablation spots and investigate the influences of different alignment parameters, which can affect the intensity distribution of a Top-Hat laser beam profile.}, subject = {D{\"u}nne Schicht}, language = {en} }