Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Please note that all times are shown in the time zone of the conference. The current conference time is: 4th Aug 2021, 01:30:39am CEST
The generation of plasma is inherent to subtractive laser processing phenomena and often determines energy absorption and damage characteristics. However, few experimental studies have directly focused on quantitatively analyzing such laser-induced plasma dynamics. Here, shadowgraph and interferogram techniques were combined in a pump-probe configuration to investigate experimentally the temporal (from sub-ps to ns) and spatial dynamics of ablation plasma generated under single-pulse, ultrashort (90-400fs) laser ablation of sapphire and copper. From the measurements, we derived the electron-plasma density and plasma distribution for each time delay. The results clearly reveal time evolution differences between the materials. In sapphire, the plasma expands predominantly perpendicularly to the surface and attains higher electron-plasma densities. In copper, more shocked air-plasma is produced which, instead, expands uniformly. These results provide new insights into the underlying physics of laser-induced plasma dynamics which could facilitate, for instance, the optimization of recent high repetition rate configurations in laser processing.
10:15am - 10:30am
Ultrafast pump-probe microscopy reveals the influence of a water layer on the early stage ablation dynamics of gold
Maximilian Spellauge1,2, Carlos Doñate-Buendia2, Stephan Barcikowski2, Bilal Gökce2, Heinz P. Huber1
1Munich University of Applied Sciences, Department of Applied Sciences and Mechatronics, Lothstrasse 34, 80335 München, Germany; 2Universität Duisburg-Essen, Lehrstuhl für Technische Chemie I, Universitätsstrasse 7, 45141 Essen, Germany
Despite the tremendous amount of research carried out in the field of pulsed laser ablation in liquids, there are only a few works available regarding the early stage ablation dynamics. A description how the liquid influences ablation on time scales ranging from pico- to microseconds would give valuable information regarding the physical processes involved. In this work we report on ultrafast pump-probe microscopy measurements of a high purity bulk gold sample immersed in air and water. Our setup enables the observation of transient dynamics ranging from pulse impact on the picosecond timescale to shock wave and cavitation bubble propagation on the nanosecond to microsecond timescale. We find that the water layer significantly influences the ablation dynamics on the whole investigated temporal range.
10:30am - 10:45am
Advanced metal ablation based on highly flexible ultra-short pulsed laser platforms
Marc Sailer1, Axel Fehrenbacher1, Aleksander Budnicki1, Steffen Rübling2, Ulf Quentin2
1TRUMPF Laser GmbH, Germany; 2TRUMPF Laser und Systemtechnik GmbH, Germany
Considering the energy efficiency and the ablation quality, micromachining of several metals is examined for different processing regimes depending on timescales from fs to µs. Choosing an optimized temporal energy deposition can address a variety of machining aspects like ablation efficiency and surface morphologies. Using the unique features of the TRUMPF TruMicro series, the temporal energy deposition can be influenced during operation on a femto- up to a microsecond timescale by tuning parameters such as the ultrashort pulse duration or employing bursts in the MHz- and GHz-regime. This enhanced flexibility paired with patent-pending process strategies leads to cutting-edge processing speeds and surface qualities.