TY - JOUR A1 - Rung, Stefan A1 - Christiansen, Anne A1 - Hellmann, Ralf T1 - Influence of film thickness on laser ablation threshold of transparent conducting oxide thin-films JF - Applied Surface Science KW - Laserablation KW - Dünnschichttechnik Y1 - 2014 VL - 305 SP - 347 EP - 351 ER - TY - CHAP A1 - Rung, Stefan A1 - Bischoff, Christian A1 - Jäger, Erwin A1 - Umhofer, Udo A1 - Hellmann, Ralf T1 - Laser thin film ablation with multiple beams and tailored beam profiles T2 - Proceedings of SPIE 8967, Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XIX KW - Thin film KW - Ablation KW - Top-Hat KW - Parallel Processing KW - Beam-Splitter KW - Laserablation KW - Dünnschichttechnik Y1 - 2014 VL - 8967 ER - TY - JOUR A1 - Rung, Stefan A1 - Rexhepi, Mal A1 - Bischoff, Christian A1 - Hellmann, Ralf T1 - Laserscribing of thin films using top-hat laser beam profiles JF - Journal of Laser Micro/Nanoengineering KW - Laser scribing KW - laser beam shaping KW - Top-Hat KW - Dünne Schicht KW - Laser Y1 - 2013 VL - 8 IS - 3 SP - 309 EP - 314 ER - TY - CHAP A1 - Rung, Stefan A1 - Rexhepi, Mal A1 - Hellmann, Ralf T1 - Beam shaping for enhanced through-put of laser ablation of transparent conductive films T2 - Proceedings of the XXVII MicroCAD International Scientific Conference KW - Laserablation Y1 - 2013 VL - 2013 ER - TY - JOUR A1 - Bischoff, Christian A1 - Rung, Stefan A1 - Hellmann, Ralf T1 - Efficient micromachining of thin film layers with nanosecond lasers – beam shaping optics improve process quality and enhance throughput JF - Laser Technik Journal KW - Laser KW - Nanosekundenbereich KW - Dünne Schicht Y1 - 2012 VL - 9 IS - 5 SP - 15 EP - 20 ER - TY - CHAP A1 - Rosenberger, Markus A1 - Belle, Stefan A1 - Hellmann, Ralf T1 - Detection of unlabeled DNA hybridization with a planar Bragg Grating Sensor T2 - XXV International MicroCAD Conference – Sensing Technologies, Miskolc (Hungary) KW - Bragg-Reflektor Y1 - 2014 IS - Section R SP - 67 EP - 72 ER - TY - JOUR A1 - Amrhein, Frank A1 - Kehrer, Martin A1 - Schreck, Timo A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael T1 - UV-LED-Bestrahlung von Vergussmaterial: Schnelle Aushärtung auch im Schatten JF - adhäsion KLEBEN & DICHTEN KW - Lumineszenzdiode Y1 - 2011 IS - 5 SP - 38 EP - 41 ER - TY - JOUR A1 - Risch, Anna A1 - Hellmann, Ralf T1 - Laser Scribing of Gallium Doped Zinc Oxide Thin Films using Picosecond Laser JF - Applied Surface Science KW - Zinkoxid KW - Dünne Schicht KW - Laser Y1 - 2014 VL - 258 IS - 5 SP - 1849 EP - 1853 ER - TY - JOUR A1 - Hellmann, Ralf A1 - Moorhouse, Colin T1 - Laser patterning of transparent electrode films, from solar panels through high-end display JF - Industrial Laser Solutions Magazine KW - Sonnenkollektor KW - Laser Y1 - 2014 IS - 11 ER - TY - JOUR A1 - Heilmann, Eva-Maria A1 - Hellmann, Ralf A1 - Seidl, Albrecht T1 - Water Jet Guided Laser Cutting of Silicon Thin Films Using 515nm Disc Laser JF - Journal of Laser Micro/Nanoengineering KW - Laserschneiden KW - Dünne Schicht Y1 - 2014 VL - 6 IS - 2 SP - 168 ER - TY - JOUR A1 - Adelmann, Benedikt A1 - Hellmann, Ralf T1 - Fast Laser Cutting Optimization Algorithm JF - Physics Procedia 12-1, Elsevier Properties S.A KW - Laserschneiden KW - Optimierung Y1 - 2011 VL - 12 IS - Part A SP - 591 EP - 598 ER - TY - JOUR A1 - Risch, Anna A1 - Hellmann, Ralf T1 - Picosecond Laser Patterning of ITO Thin Films JF - Physics Procedia 12-1, Elsevier Properties S.A KW - Laserbearbeitung KW - Dünne Schicht Y1 - 2014 IS - 12 SP - 133 EP - 140 ER - TY - CHAP A1 - Heilmann, Eva-Maria A1 - Hellmann, Ralf T1 - High Speed Fibre Laser Material processing of Stainless Steel Tapes Under Tension T2 - XXV International MicroCAD Conference - Material Processing Technologies, Miskolc (Hungary), 21-25 KW - Lasertechnologie Y1 - 2011 ER - TY - CHAP A1 - Adelmann, Benedikt A1 - Hellmann, Ralf T1 - Different modulation schemes in fibre laser cutting T2 - Proceeding XXV microCAD, International scientific conference, 2011, Section K: Material science/Material processing technologies KW - Laserschneiden KW - Faserlaser Y1 - 2014 SP - 1 EP - 6 ER - TY - CHAP A1 - Adelmann, Benedikt A1 - Hellmann, Ralf T1 - DOE based optimization of fibre laser cutting of metals T2 - Proceeding XXV microCAD, International scientific conference, 2011, Section K: Material science/Material processing technologies KW - Laserschneiden KW - Faserlaser Y1 - 2014 SP - 7 EP - 12 ER - TY - CHAP A1 - Risch, Anna A1 - Hellmann, Ralf T1 - Laser induced modification of GZO thin film T2 - Proceeding XXV microCAD, International scientific conference, 2011, Section K: Material science/Material processing technologies KW - Laser KW - Dünne Schicht Y1 - 2014 SP - 69 EP - 74 ER - TY - CHAP A1 - Risch, Anna A1 - Hellmann, Ralf T1 - ITO thin film laser patterning by picosecond laser T2 - Proceeding XXV microCAD, International scientific conference, 2011, Section K: Material science/Material processing technologies KW - Laserbearbeitung Y1 - 2014 SP - 63 EP - 68 ER - TY - CHAP A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Hellmann, Ralf T1 - Optical interrogation of chemical and temperature bragg grating sensors using tunable fiber coupled bandpass filter T2 - Proceeding XXV microCAD, International scientific conference, 2011, Section H KW - Bragg-Reflektor Y1 - 2014 SP - 25 EP - 30 ER - TY - CHAP A1 - Belle, Stefan A1 - Rosenberger, Manuel A1 - Hellmann, Ralf T1 - Optical fibre sensing in the production process and storage of biofuels T2 - Proceeding XXV microCAD, International scientific conference, 2011, Section A KW - Biokraftstoff Y1 - 2014 SP - 21 EP - 26 ER - TY - JOUR A1 - Belle, Stefan A1 - Rosenberger, Manuel A1 - Hellmann, Ralf T1 - Evanescent wave planar bragg grating sensor for real-time detection of unlabelled biomolecules JF - Optics Express KW - Bragg-Reflektor KW - Biomolekül Y1 - 2014 ER - TY - JOUR A1 - Girschikofsky, Maiko A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Brutschy, Malte A1 - Waldvogel, Siegfried A1 - Hellmann, Ralf T1 - Optical planar bragg grating sensor for real-time detection of benzene, toluene und xylene in solvent vapour JF - Sensors & Actuators, B - Chemical KW - Bragg-Reflektor Y1 - 2014 VL - 171/172 IS - 8/9 SP - 338 EP - 342 ER - TY - JOUR A1 - Girschikofsky, Maiko A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Brutschy, Malte A1 - Waldvogel, Siegfried A1 - Hellmann, Ralf T1 - Highly sensitive detection of naphthalene in solvent vapor using a functionalized PBG refractive index sensor JF - Sensors KW - Bragg-Reflektor KW - Sensor Y1 - 2014 U6 - https://doi.org/10.3390/s120202018 VL - 12 IS - 2 SP - 2018 EP - 2025 ER - TY - CHAP A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Hellmann, Ralf T1 - Detection of biochemical reaction and DNA hybridization using a planar bragg grating sensor T2 - Proceeding SPIE, Vol. 8073, article id: 80730C KW - Bragg-Reflektor KW - Sensor Y1 - 2014 U6 - https://doi.org/10.1117/12.886785 IS - 8073 ER - TY - JOUR A1 - Risch, Anna A1 - Christiansen, Anne A1 - Hellmann, Ralf A1 - Gockel, Tilo T1 - Laserstrukturierung vonTCOs zur Herstellung organischer Leuchtdioden JF - Elektor, Sonderheft LEDs 3 KW - Transparent-leitendes Oxid KW - Lumineszenzdiode KW - Laserbearbeitung Y1 - 2011 IS - 9 SP - 39 EP - 41 ER - TY - JOUR A1 - Amrhein, Frank A1 - Kehrer, Martin A1 - Schreck, Timo A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael T1 - More efficient curing of UV sensitive mounting materials JF - Practical metallography KW - Aushärtung Y1 - 2014 VL - 48 IS - 7 SP - 356 EP - 364 ER - TY - CHAP A1 - Risch, Anna A1 - Hühnlein, Kristof A1 - Knöll, Jürgen A1 - Hellmann, Ralf T1 - Laserscribing of transparent conductive oxides - a comparative study using nanosecond and picosecond pulsed solid state lasers T2 - Proceedings of the 20st International Scientific Conference, Mittweida, 2009 KW - Festkörperlaser Y1 - 2014 ER - TY - CHAP A1 - Kaloumenos, Mareiki A1 - Amrhein, Frank A1 - Glaab, Johannes A1 - Sauer, Michael A1 - Hellmann, Ralf A1 - Kaloudis, Michael T1 - Development of a UV-Light Source with Highest Power Density Based on Light Emitting Diode Technology for Applications in Production Engineering, in Production Engineering and manufacturing Systems T2 - Proceedings of the XXIV International Scientific Conference Miskolc, Ungarn KW - Lumineszenzdiode Y1 - 2010 ER - TY - JOUR A1 - Hellmann, Ralf A1 - Glaab, Johannes A1 - Gockel, Tilo T1 - Wasserentkeimung mit UV-Leuchtdioden JF - Elektor Sonderheft, LEDs 2 KW - Wasseraufbereitung KW - Lumineszenzdiode Y1 - 2010 VL - 2010 IS - 2 SP - 40 EP - 45 PB - Elektor-Verlag CY - Aachen ER - TY - JOUR A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael A1 - Amrhein, Frank A1 - Glaab, Johannes A1 - Kaloumenos, Mareiki A1 - Sauer, Michael A1 - Gockel, Tilo T1 - LUVLED - UV-Leistungslichtquelle auf Leuchtdiodenbasis JF - Elektor Sonderheft, LEDs 2 KW - Lumineszenzdiode Y1 - 2010 VL - 2011 IS - 2 SP - 57 EP - 63 PB - Elektor-Verlag CY - Aachen ER - TY - JOUR A1 - Amrhein, Frank A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael A1 - Kaloumenos, Mareiki T1 - Vergleich der thermischen Eigenschaften unterschiedlicher insulated metal substrat-Leiterplatten JF - PLUS, Leiterplattentechnik KW - Gedruckte Schaltung KW - Trägersubstanz Y1 - 2010 IS - 8 SP - 1758 PB - Hanser Verlag CY - München ER - TY - JOUR A1 - Heilmann, Eva-Maria A1 - Kowalski, Thomas A1 - Hellmann, Ralf A1 - Teigelkötter, Johannes T1 - Water Jet Guided Laser Cutting of High Temperature Superconductors JF - Journal of Laser Micro/Nanoengineering KW - laser KW - Laserschneiden Y1 - 2013 U6 - https://doi.org/10.2961/jlmn.2013.01.0014 VL - 8 IS - 1 SP - 70 EP - 74 ER - TY - JOUR A1 - Hellmann, Ralf A1 - Gockel, Tilo T1 - Optische Charakterisierung von Leuchtdioden JF - Zeitschrift ELEKTOR, Sonderheft LED-Special 4 – Leuchtdioden in Theorie und Praxis, 2012 KW - Leuchtdioden KW - Lumineszenzdiode Y1 - 2012 IS - 9 SP - 40 EP - 46 ER - TY - CHAP A1 - Kalmár, László A1 - Hellmann, Ralf A1 - Régert, Tamás A1 - Varga, Zoltan T1 - Numerical investigation of unsteady heat transport procedure in high power LED module T2 - GEP KW - LED module KW - Lumineszenzdiode Y1 - 2012 VL - 2012 IS - 1 SP - 43 EP - 46 ER - TY - JOUR A1 - Schneider, Johannes A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael A1 - Gockel, Tilo T1 - LUVLED III – Optimierung eines Kühlkonzeptes zur Aktivluftkühlung eines Hochleistungs-UV-LED-Moduls JF - Zeitschrift ELEKTOR, Sonderheft LED-Special 4 – Leuchtdioden in Theorie und Praxis, 2012 KW - UV-LED Modul KW - Lumineszenzdiode Y1 - 2012 IS - 9 SP - 20 EP - 29 ER - TY - CHAP A1 - Hühnlein, Kristof A1 - Tschirpke, Katrin A1 - Hellmann, Ralf T1 - Optimisation of laser cutting using design of experiment - A comparative study of cutting thin ceramic layers using a fibre laser and a CO2 laser T2 - Physics procedia T2 - 6th international conference on laser assisted net shape engineering KW - Laserschneiden Y1 - 2014 SN - 1875-3892 VL - 5 IS - Part B SP - 243 EP - 252 ER - TY - JOUR A1 - Risch, Anna A1 - Hühnlein, Kristof A1 - Knöll, Jürgen A1 - Hellmann, Ralf T1 - Picosecond and nanosecond pulsed laserscribing on transparent conductive indium tin oxide JF - Journal of Material processing technolgies JF - Proceedings of the XXIV international scientific conference Miskolc, Ungarn KW - Laserbearbeitung Y1 - 2014 SN - 0924-0136 ER - TY - JOUR A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael T1 - Neuartige UV-Lichtquelle auf Leuchtdiodenbasis, Packaging und Hybridschaltungen JF - PLUS KW - Lumineszenzdiode Y1 - 2010 IS - 2 PB - Leuze-Verlag ER - TY - CHAP A1 - Glaab, Johannes A1 - Hellmann, Ralf T1 - Germicidal potential of ultraviolet-LED emitting different wavelength for the inactivation of indigenous coliform bacteria T2 - Water research conference, Lissabon, Portugal KW - Lumineszenzdiode KW - Kolibakterium Y1 - 2014 ER - TY - CHAP A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Hellmann, Ralf T1 - Optical interrogation of bragg grating sensors using tunable fibre based bandpass filter T2 - Proceedings of the 20st international science conference, Mittweida KW - Bragg-Reflektor KW - Sensor Y1 - 2014 ER - TY - CHAP A1 - Belle, Stefan A1 - Scheurich, Steffen A1 - Hellmann, Ralf T1 - Interrogation water content in organic solvents by planar bragg grating sensors T2 - Proceedings SENSOR KW - Bragg-Reflektor KW - Sensor Y1 - 2014 SN - 978-3-9810993-6-2 IS - Vol. II, P3.2 SP - 324 EP - 329 ER - TY - CHAP A1 - Scheurich, Steffen A1 - Belle, Stefan A1 - Hellmann, Ralf A1 - So, Sik A1 - Sparrow, Ian A1 - Emmerson, Greg T1 - Application of a silica-on-silicon planar optical waveguide. Bragg grating sensor for organic liquid compound detection T2 - SPIE Optics an optoelectronics conference, Proceedings of SPIE, Vol. 7356, Prag, CR KW - Bragg-Reflektor KW - Sensor Y1 - 2014 SN - 978-0819476302 IS - 7356 ER - TY - CHAP A1 - Scheurich, Steffen A1 - Belle, Stefan A1 - Hellmann, Ralf A1 - So, Sik A1 - Sparrow, Ian A1 - Emmerson, Greg T1 - Planar optical waveguide bragg grating chemical sensor for online process control T2 - 3rd integrated optics - sensors, sensing structures and methodes Korbielow, PL KW - Bragg-Reflektor KW - Sensor Y1 - 2014 ER - TY - JOUR A1 - Hock, Klaus A1 - Adelmann, Benedikt A1 - Hellmann, Ralf T1 - Comparative study of remote fiber laser and water-jet guided laser cutting of thin film metal sheets JF - Physics procedia KW - laser KW - Laserschneiden Y1 - 2012 VL - 39 SP - 225 EP - 231 ER - TY - CHAP A1 - Kalmár, László A1 - Hellmann, Ralf A1 - Régert, Tamás A1 - Varga, Zoltan T1 - Numerical investigation of heat transport procedure in high power LED modules T2 - Proceedings of the XXVI International MicroCAD Conference, Miskolc (Hungary) KW - heat transport procedure KW - Lumineszenzdiode KW - Wärmeübertragung Y1 - 2012 SP - 43 EP - 46 ER - TY - CHAP A1 - Bischoff, Christian A1 - Jäger, Erwin A1 - Rung, Stefan A1 - Hellmann, Ralf T1 - Diffractive beam shaping optics for efficient micromachining T2 - Proceedings of the LASYS (Internationale Fachmesse für Laser-Materialbearbeitung) – SLT (Stuttgarter Lasertage) 2012 KW - micromachining KW - Laserbearbeitung Y1 - 2012 ER - TY - CHAP A1 - Koller, Georg A1 - Hessler, Steffen A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Hellmann, Ralf T1 - Micro-structured optical waveguide fabrication in PMMA using low frequency reactive ion etching T2 - Proceedings of the XXVI International MicroCAD Conference – Sensing Technologies, Miskolc (Hungary) KW - waveguide fabrication KW - Wellenleiter Y1 - 2012 ER - TY - CHAP A1 - Girschikofsky, Maiko A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Brutschy, Malte A1 - Waldvogel, Siegfried A1 - Hellmann, Ralf T1 - α-Cyclodextrin functionalized planar Bragg grating sensor for the detection of small arene traces in solvamt vapour T2 - 14th international meeting on chemical sensors (IMCS 2012) KW - sensor detection KW - Bragg-Reflektor Y1 - 2012 SN - 978-3-9813484-2-2 U6 - https://doi.org/10.5162/IMCS2012/7.5.1 SP - 646 EP - 648 ER - TY - CHAP A1 - Rung, Stefan A1 - Hellmann, Ralf T1 - Laser scribing of metallized transparent conductive oxide – A comparative study using top hat and Gaussian beam profiles T2 - Proceedings of the XXVI International MicroCAD Conference – Material Processing Technologies KW - laser scribing KW - Laserbearbeitung KW - Laserritzen Y1 - 2012 ER - TY - CHAP A1 - Girschikofsky, Maiko A1 - Rosenberger, Manuel A1 - Belle, Stefan A1 - Hellmann, Ralf T1 - Surface modifications of planar bragg grating refractive index sensors for gas detection T2 - Proceedings of the XXVI International MicroCAD Conference – Sensing Technologies, Miskolc (Hungary) KW - surface modification KW - Bragg-Reflektor Y1 - 2012 ER - TY - JOUR A1 - Preusch, Florian A1 - Rung, Stefan A1 - Hellmann, Ralf T1 - Influence of Polishing Orientation on the Generation of LIPSS on Stainless Steel JF - Journal of Laser Micro/Nanoengineering KW - Laserbearbeitung KW - Nicht rostender Stahl Y1 - 2016 U6 - https://doi.org/10.2961/jlmn.2016.01.0025 VL - 11 SP - 137 EP - 142 ER - TY - JOUR A1 - Rung, Stefan A1 - Barth, Johannes A1 - Hellmann, Ralf T1 - Characterization of Laser Beam Shaping Optics Based on Their Ablation Geometry of Thin Films JF - Micromachines N2 - 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. KW - Dünne Schicht KW - Laserablation Y1 - 2014 VL - 5 IS - 4 SP - 943 EP - 953 ER -