We report on the efficient use of high-energy, multi-millijoule ultrafast laser sources to operate well-known low-energy micro-machining applications such as surface texturing of transparent materials. A sophisticated optical system that employs micro-lens arrays is used enabling flexible beam splitting and thus parallel processing. Here, the number of foci can be varied ranging from a few ten up to a few hundred spots. As selected examples we will present efficient glass surface texturing using 8mJ and 200W of an industry grade ultrafast laser platform. Our micro-lens-array-based optical head is generating high-quality dimples on a (100 x 100)mm2 with filling factors above 25% area in less than 15s.

Femtosecond lasers emit short pulses whose temporal width is in the range of less than a picosecond to a few femtoseconds (fs), thereby enabling extremely high peak-power machining with minimum thermal damages. Herein we employed femtosecond laser pulses as a versatile tool for surface processing of textiles made of 2 polymers commonly used in textile industry, Polyethylene terephthalate (PET), and Polyamide66 (PA66). This work focuses on a comparison of ultraviolet (UV, 257 nm) and infrared (IR, 800 and 1030 nm) femtosecond laser irradiation at the surface of the polymers PET and PA66, possible hybridization with chemical grafting, as well as the resulting liquid repellency from different process scenarios. The study highlights the different responses of the polymers to the laser irradiations and possible routines for surface functionalization of the textiles.

Ultrafast high-energy laser systems allow performing some of the most advanced experiments in physical sciences, such as electron and ion acceleration, as well as high-harmonic and XUV generation. In the past decades, together with the development of optics, the field has tremendously developed towards high-energy/high-power ultrafast lasers. SAVANNA-HP is one of the latest developments towards this goal; a stretched flexible hollow-core fiber compressor designed for high-power lasers with ten mJ pulses and an average power of more than hundred Watts. The talk will cover the development and commissioning of such a device as well as its performance revealing state-of-the-art results.

Laser Beam Welding (LBW) of complex materials, such as ferritic and austenitic steel, is challenging. An appropriate beam shape improves the process by stabilizing the keyhole. A methodology for tailoring the beam shape has been developed. The appropriate shape for LBW of 1mm thick steel is an inner intense spot and a background top-hat shape. A dynamic beam shaper based on Multi-Plane Light Conversion has been developed: the ratio between the shapes and the back shape dimensions can be adjusted. The optical performance and the impact on the quality of the process with a 8kW 1.07µm laser are described.

We demonstrate the use of Variable Beam Profile (VBP) lasers for welding e-mobility materials. The VBP laser uses dual beam output to produce a central spot, surrounded by another concentric ring of laser light. The use of VBP lasers results in a welding process that is more stable and consistent during welding. This paper highlights welding results achieved using a VBP fibre laser, with power ranging from 6kW to 12kW on weld joints including dissimilar joints between copper and aluminium-based alloys. Results from VBP lasers are compared with those obtained via e.g. pulse shaping of traditional single beam lasers.

The laser technology is key to the development of the e-mobility. We demonstrate how an optimal laser beam shaping enables high speed and high quality copper welding for the battery cells manufacturing. The beam shaping parameters are explored and optimized and the optical performance is assessed. The process window is described for four sets of shape parameters as well as the comparison with an unshaped beam. The quality in each cases for different speed and average power is discussed. An optimal process at 6m/min and 8kW is obtained. At last, different welding configuration, such as transparent welding, are described.

We present our progress on developing an innovative compact thulium-based fiber CPA emitting at 2 µm central wavelength. The laser parameters comprise >100 µJ pulse energy at an average power of >30W. The system comes in an industrial-grade platform optimized for long-term operation and its optimized packaging is well suited for the integration in laser machines for materials processing. The laser parameters are ideally suited for processing semiconductors, e.g. silicon by microwelding or cutting of filaments.