High power parallel ultrashort pulse laser processing

Abstract

The class of ultra-short-pulse (USP) laser sources are used, whenever high precession and high quality material processing is demanded. These laser sources deliver pulse duration in the range of ps to fs and are characterized with high peak intensities leading to a direct vaporization of the material with a minimum thermal damage. With the availability of industrial laser source with an average power of up to 1000W, the main challenge consist of the effective energy distribution and disposition. Using lasers with high repetition rates in the MHz region can cause thermal issues like overheating, melt production and low ablation quality. In this paper, we will discuss different approaches for multibeam processing for utilization of high pulse energies. The combination of diffractive optics and conventional galvometer scanner can be used for high throughput laser ablation, but are limited in the optical qualities. We will show which applications can benefit from this hybrid optic and which improvements in productivity are expected. In addition, the optical limitations of the system will be compiled, in order to evaluate the suitability of this approach for any given application

In Situ Analysis of Ultrashort Pulse Burst Ablation via Transmission Pump Probe Imaging

“…Since the optimum operating point for the most efficient ablation of metals is known to be in the range of e²-times the ablation threshold [9,13] the application of high average powers is challenging. However, there are three promising approaches being investigated to overcome this limitation and bringing powers into effect: (1) The utilization of high repetition rates [4,12,14], (2) pulse bursts [6,[15][16][17][18] and (3) the parallelization by multi-beam optics [11,[19][20][21][22]. The multi-beam optic splits the laser beam in multiple partial beams and therefore the high pulse energy is distributed between these spots.…”

Dynamic, Adaptive Inline Process Monitoring for Laser Material Processing by Means of Low Coherence Interferometry

“…One way to improve these factors is to laser-texture the steel sheets. Laser micro structuring is an excellent solution due to its capacity to create functional surface structures on a micrometer scale [8][9][10][11][12][13][14][15]. The aim of the Horizon 2020 research project ESSIAL is, among other things, to improve the magnetic properties, as described above, by laser structuring of the steel sheets.…”