Translator Disclaimer
Paper
2 March 2020 Divide-and-conquer laser beam deflection system: Fast, wide-ranging, and flexible
Author Affiliations +
Abstract
In micro-material processing with ultrashort laser pulses (USP), the surface quality during drilling and thin film ablation varies with the scanning speed and the pulse repetition rate. However, while high pulse repetition rates tend to be desirable, local heat accumulation caused by increasing pulse overlap is counterproductive. Thus, the scanning speed must be scaled with the pulse repetition rate, preferably by supplementing the already existing setup.

In this work, we present a dynamic extension through the combination of an acousto-optical deflector (AOD) with a galvanometer scanner. This combines the best of two worlds: the dynamic beam deflection of the AOD and the large scanning field of the galvanometer scanner. The integrated AOD is able to deflect the laser beam pulse by pulse within its scanning field and to modulate the beam intensity simultaneously. The mechanical limitations and problems of the galvanometer scanner, such as vibrations and overshoots due to fast mirror rotations, can be specifically compensated by the high precision of the AOD. As a result, in addition to process time reduction, the surface and image quality improves significantly. In any case, the laser source needs synchronization with the AOD because the propagation of sound waves within the AOD crystal is slower than the laser pulse propagation through the medium. In the first step, a comparatively slow AOD based on tellurium dioxide with a transversal crystal alignment is used. The process time of a thin film ablation with 4 μJ at 1 MHz was reduced considerably by applying a USP laser system (Coherent Monaco).
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Patrick A. Taschner, Jan Düsing, Jürgen Koch, Peter Jäschke, Stefan Kaierle, and Ludger Overmeyer "Divide-and-conquer laser beam deflection system: Fast, wide-ranging, and flexible", Proc. SPIE 11268, Laser-based Micro- and Nanoprocessing XIV, 112681G (2 March 2020); https://doi.org/10.1117/12.2546162
PROCEEDINGS
6 PAGES


SHARE
Advertisement
Advertisement
Back to Top