Multi-Beam Processing with Individually Addressable Beamlets: Calibration & Data Processing

Multibeam processing with ultra-short pulsed lasers attracts increasing attention as upscaling technology for laser material processing. While static multibeam approaches for periodic patterns are already entering industry applications, multibeam solutions for the processing of arbitrary geometries are still missing. The demand for high speed, high volume structuring of large surfaces exists, e.g. for molding applications, electronics and photovoltaic, and pushes the development of high-power ultrashort pulsed lasers and the corresponding beam handling systems. To gain the flexibility to process arbitrary structures with a multibeam setup, a flexible, individual control of each beam in the multibeam bundle needs to be realized. This requires significant control of the different modulators typically combined with a galvanometer-scanner based processing setup. A concept for such an adapted processing system is discussed, incorporating acusto-optic modulators for flexible beam switching and a Field Programmable Gate Array for real-time control. A concept to compensate optical aberrations is introduced, and the required algorithms to generate the control commands for the galvanometer scanner and acusto-optic modulators from the provided structure is demonstrated. Finally, the implementation of the real-time scanner-position based switching of the acusto-optic modulators is presented. Keywords: multibeam, ultra-short pulsed laser, kilo-watt laser, micro structuring, control system, galvanometer scanner, scanfield calibration, FPGA, system technology