@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{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{FranzRothRungetal.2021, author = {Franz, Daniel and Roth, Gian-Luca and Rung, Stefan and Esen, Cemal and Hellmann, Ralf}, title = {Superimposed beam deflection using acousto-optical deflectors in combination with a galvanometer scanner}, series = {Lasers in Manufacturing - LiM 2021}, booktitle = {Lasers in Manufacturing - LiM 2021}, year = {2021}, subject = {Galvanometer}, language = {en} }