Darmstadt 2008 – scientific programme
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SYLM: Symposium Lasermaterialbearbeitung
SYLM 4: Strahlführung II und Nanostrukturierung
SYLM 4.1: Invited Talk
Thursday, March 13, 2008, 11:00–11:30, 2B/C
High precision refractive beam shaping: From the solution of the Maxwell equations to industrial material processing using short pulses — •Björn Gütlich, Thomas Mitra, Oliver Homburg, Dirk Hauschild, Lutz Aschke, and Vitalij Lissotschenko — LIMO Lissotschenko Mikrooptik GmbH, Bookenburgweg 4-8, 44319 Dortmund, Germany, www.limo.de
Short pulse, high power laser sources are used in a large variety of applications for material processing like cutting, drilling, annealing, micro-machining, ablation and micro-lithography. To meet the requirements of these applications the generation of appropriate beam profiles is decisive. LIMO has developed its own software based on the Maxwell equations to realize the best result for the beam shaping task. Various beam shaping principles, e.g. phase shifting for single mode lasers, beam mixing for multi-mode lasers are discussed here. Widely used geometries are square, rectangular light fields or light lines. For these or other customized solutions the advantages of novel micro-lens arrays with asymmetric lens profiles are demonstrated. Based on LIMO’s unique production technology with computer-aided design, free-form micro-lens surfaces can be structured cost-effectively on wafer-basis into any kind material for high power short pulse lasers. Particular emphasis is put on refractive Gaussian-to-tophat converters for single mode lasers and their advantages in micro-machining. Patterning results in plastics (polyamide) and ceramics (Al2O3) are presented and improved redevelopments of the beam shaping system for industrial applications are introduced.