@inproceedings{KeferSchmaussHellmann2023, author = {Kefer, Stefan and Schmauss, Bernhard and Hellmann, Ralf}, title = {Sapphire-Based Planar Bragg Grating Devices}, series = {28th International Conference on Optical Fiber Sensors}, booktitle = {28th International Conference on Optical Fiber Sensors}, isbn = {978-1-957171-30-2}, doi = {10.1364/OFS.2023.W2.4}, year = {2023}, abstract = {This study reports on the long-term stability and the high-temperature capability of sapphire-based photonic crystal waveguides with integrated Bragg gratings. Furthermore, their Bragg grating reflectivity as well as their temperature sensitivity is quantified.}, subject = {Bragg-Reflektor}, language = {en} } @inproceedings{KeferSchmaussHellmann2021, author = {Kefer, Stefan and Schmauss, Bernhard and Hellmann, Ralf}, title = {POLYMER PLANAR BRAGG GRATINGS BASED ON BULK CYCLIC OLEFIN COPOLYMERS: FABRICATION AND FUNCTIONALIZATION}, series = {Proceedings of Student Conference on Sensors, Systems and Measurement 2021}, booktitle = {Proceedings of Student Conference on Sensors, Systems and Measurement 2021}, isbn = {978-80-01-06822-9}, year = {2021}, subject = {Bragg-Reflektor}, language = {en} } @inproceedings{ScheurichBelleHellmannetal.2009, author = {Scheurich, Steffen and Belle, Stefan and Hellmann, Ralf and So, Sik and Sparrow, Ian and Emmerson, Greg}, title = {Planar optical waveguide bragg grating chemical sensor for online process control}, series = {3rd integrated optics - sensors, sensing structures and methodes Korbielow, PL}, booktitle = {3rd integrated optics - sensors, sensing structures and methodes Korbielow, PL}, year = {2009}, subject = {Bragg-Reflektor}, language = {en} } @inproceedings{HuehnleinTschirpkeHellmann2010, author = {H{\"u}hnlein, Kristof and Tschirpke, Katrin and Hellmann, Ralf}, title = {Optimisation of laser cutting using design of experiment - A comparative study of cutting thin ceramic layers using a fibre laser and a CO2 laser}, series = {Physics procedia}, volume = {5}, booktitle = {Physics procedia}, number = {Part B}, issn = {1875-3892}, pages = {243 -- 252}, year = {2010}, subject = {Laserschneiden}, language = {en} } @inproceedings{LutzSchwarzRungetal.2021, author = {Lutz, Christian and Schwarz, Simon and Rung, Stefan and Marx, Jan and Esen, Cemal and Hellmann, Ralf}, title = {Optical system for multi Bessel beam high power ultrashort pulsed laser processing using a spatial light modulator}, series = {Lasers in Manufacturing - LiM 2021}, booktitle = {Lasers in Manufacturing - LiM 2021}, year = {2021}, abstract = {We report on an optical setup for multi Bessel beam processing combining a refractive axicon and a spatial light modulator. Based on their particular beam profile, Bessel beams exhibit various advantages over conventional Gaussian beams for ultrashort pulsed laser processing. Especially for micromachining of transparent materials, applications such as micro-hole drilling or the generation of voids benefit from the increased focal length of the applied Bessel beam. In addition, on account of the significantly increased average output power of industrial ultrashort pulsed lasers over the last years, there is a high demand on multi spot applications for using the available laser power in efficient production processes. Our optical concept combines the dynamic possibilities of beam splitting using spatial light modulator with the benefits of Bessel beams facilitating multi Bessel beam processing.}, subject = {Ultrakurzzeitlaser}, language = {en} } @inproceedings{RosenbergerBelleHellmann2011, author = {Rosenberger, Manuel and Belle, Stefan and Hellmann, Ralf}, title = {Optical interrogation of chemical and temperature bragg grating sensors using tunable fiber coupled bandpass filter}, series = {Proceeding XXV microCAD, International scientific conference, 2011, Section H}, booktitle = {Proceeding XXV microCAD, International scientific conference, 2011, Section H}, pages = {25 -- 30}, year = {2011}, subject = {Bragg-Reflektor}, language = {en} } @inproceedings{RosenbergerBelleHellmann2009, author = {Rosenberger, Manuel and Belle, Stefan and Hellmann, Ralf}, title = {Optical interrogation of bragg grating sensors using tunable fibre based bandpass filter}, series = {Proceedings of the 20st international science conference, Mittweida}, booktitle = {Proceedings of the 20st international science conference, Mittweida}, year = {2009}, subject = {Bragg-Reflektor}, language = {en} } @inproceedings{BelleRosenbergerHellmann2011, author = {Belle, Stefan and Rosenberger, Manuel and Hellmann, Ralf}, title = {Optical fibre sensing in the production process and storage of biofuels}, series = {Proceeding XXV microCAD, International scientific conference, 2011, Section A}, booktitle = {Proceeding XXV microCAD, International scientific conference, 2011, Section A}, pages = {21 -- 26}, year = {2011}, subject = {Biokraftstoff}, language = {en} } @inproceedings{AdelmannNeumeierSchleieretal.2015, author = {Adelmann, Benedikt and Neumeier, Benedikt and Schleier, Max and Wilmann, Eugen and Hellmann, Ralf}, title = {Optical cutting tear detection system for industrial fiber laser based cutting machines}, series = {Lasers in Manufacturing Conference 2015}, booktitle = {Lasers in Manufacturing Conference 2015}, year = {2015}, subject = {Laserschneiden}, language = {en} } @inproceedings{KalmarHellmannRegertetal.2011, author = {Kalm{\´a}r, L{\´a}szl{\´o} and Hellmann, Ralf and R{\´e}gert, Tam{\´a}s and Varga, Zoltan}, title = {Numerical simulation of heat transfer procedure in high power LED modules}, series = {Proceedings of the 12th technical and scientific meeting}, booktitle = {Proceedings of the 12th technical and scientific meeting}, pages = {18 -- 20}, year = {2011}, subject = {Lumineszenzdiode}, language = {en} }