TY - JOUR A1 - Zettl, Julian A1 - Esen, Cemal A1 - Hellmann, Ralf T1 - Fundamental Considerations and Analysis of the Energy Distribution in Laser Turning with Ultrashort Laser Pulses JF - mdpi Micromachines N2 - This article discusses the process of the laser turning of rotational symmetric, cylindrical components using ultrashort laser pulses with respect to the geometrical conditions and the resulting energy distribution during the laser turning process. As a result, process predictions and potential process optimizations are feasible. Particular attention is drawn to the laser spot formation on the cylindrical surface of the work piece in conjunction with the positioning of the laser beam relative to the rotation axis of the specimen. Based on fundamental calculations and experimental results, an optimum processing strategy is discussed, whereat the use of a trepanning optic in the laser turning process and the forming of a particular surface structure is additionally being issued. KW - ultrashort pulse laser KW - laser turning KW - tangential processing KW - trepanning optic KW - Ultrakurzzeitlaser Y1 - 2023 UR - https://www.mdpi.com/2072-666X/14/10/1838 U6 - https://doi.org/10.3390/mi14101838 VL - 14 IS - 10 SP - 1 EP - 15 ER - TY - JOUR A1 - Rung, Stefan A1 - Häcker, Niklas A1 - Hellmann, Ralf T1 - Thermal imaging of high power ultrashort pulse laser ablation of alumina towards temperature optimized micro machining strategies JF - IOP Conference Series: Materials Science and Engineering KW - Ultrakurzzeitlaser KW - Aluminiumoxide Y1 - 2021 UR - https://iopscience.iop.org/article/10.1088/1757-899X/1135/1/012027 U6 - https://doi.org/0.1088/1757-899X/1135/1/012027 VL - 1135 IS - 012027 SP - 1 EP - 9 ER - TY - JOUR A1 - Rung, Stefan A1 - Hellmann, Ralf T1 - Laser-Induced Period Surface Structures to Improve Solderability of Electrical Solder Pads JF - Applied Sciences KW - Laserstrahllöten Y1 - 2021 UR - https://www.mdpi.com/2076-3417/12/1/80/htm U6 - https://doi.org/10.3390/app12010080 VL - 2022 IS - 12/1 SP - 80 EP - 88 ER - TY - JOUR A1 - Roth, Gian-Luca A1 - Rung, Stefan A1 - Esen, Cemal A1 - Hellmann, Ralf T1 - Microchannels inside bulk PMMA generated by femtosecond laser using adaptive beam shaping JF - Optics Express N2 - In this contribution, we report on the generation of internal microchannels with basically unlimited channel length inside of PMMA bulk material by femtosecond laser. A precisely controllable and stable circular channel cross section is obtained by using a spatial light modulator to compensate the writing depth depending spherical aberration. Furthermore, the generation of a rotatable elliptical input beam by adaptive optics ensures a fitting of the beam shaping to the writing direction. In this study, we report on both, the effect of the ellipticity of the input beam and the effect of a correction of the spherical aberration on the circularity of the resulting internal microchannels. Moreover, we demonstrate the application of this writing technique by creating microfluidic testing structures inside of a transparent standard polymer. KW - Femtosekundenlaser KW - Polymethylmethacrylate Y1 - 2020 VL - 28 IS - 4 SP - 5801 EP - 5811 ER - TY - JOUR A1 - de Ortueta, Diego A1 - Magnago, Thomas A1 - Triefenbach, Nico A1 - Arba-Mosquera, Samuel A1 - Sauer, Udo A1 - Brunsmann, Ulrich T1 - In vivo measurements of the thermal load during the ablation in high-speed laser corneal refractive surgery JF - Journal of Refractive Surgery KW - Laser KW - Medizin Y1 - 2014 VL - 28 IS - 1 SP - 53 EP - 58 ER - TY - JOUR A1 - Brunsmann, Ulrich A1 - Sauer, Udo A1 - Dressler, Katharina A1 - Triefenbach, Nico A1 - Arba-Mosquera, Samuel T1 - Minimisation of the thermal load of the ablation in high-speed laser corneal refractive surgery: the "intelligent thermal effect control" of the AMARIS plattform JF - Journal of modern optics KW - Laser KW - Medizin Y1 - 2014 VL - 57 IS - 6 SP - 466 EP - 479 ER - TY - JOUR A1 - Brunsmann, Ulrich A1 - Sauer, Udo A1 - Arba-Mosquera, Samuel A1 - Magnago, Thomas A1 - Triefenbach, Nico T1 - Evaluation of thermal load during laser corneal refractive surgery using infrared thermography JF - Infrared Physics & technology KW - Laser KW - Medizin KW - Infrarotthermographie Y1 - 2014 VL - 53 IS - 5 SP - 342 EP - 347 ER - TY - JOUR A1 - Brunsmann, Ulrich A1 - Tille, Thomas T1 - High Resolution Readout of Metal Oxide Gas Sensors Using Time-to-Digital Conversion JF - IEEE Electronics Letters KW - Metalloxid-Gassensor Y1 - 2014 U6 - https://doi.org/10.1049/el:20062546 VL - 42 IS - 20 SP - 1148 EP - 1149 ER - TY - JOUR A1 - Daus, Andreas T1 - Leben auf dem Mikrochip – Biosensoren auf der Basis von Mikroelektroden-Arrays JF - Labor & More KW - Biosensoren KW - Biosensor KW - Mikroelektrode KW - Array Y1 - 2012 VL - 2012 IS - 8 SP - 20 EP - 24 ER -