Characterization of a hybrid scanning system comprising acousto-optical deflectors and galvanometer scanners
Daniel Franz, Tom Häfner, Tim Kunz, Gian‐Luca Roth, Stefan Rung, Cemal Esen, Ralf Hellmann
Abstract
Abstract We report on the characterization of a hybrid laser scanning system using acousto-optical deflectors in combination with galvanometer scanners for ultra-short pulse laser material processing. The hybrid scanning system is characterized by the roundness of static pulsed ablations of metal thin film on a transparent substrate within the acousto-optical scanning field at different galvanometer scanner deflection angles and laser focal positions. An ablation roundness of more than 90% is reached in a defocusing range of 200 $$\upmu \text{m}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>μ</mml:mi> <mml:mtext>m</mml:mtext> </mml:mrow> </mml:math> within a galvanometer scanfield of 900 $$\text{mm}^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mtext>mm</mml:mtext> <mml:mn>2</mml:mn> </mml:msup> </mml:math> , corresponding to approximately 74% of the usable scan area of the f -theta lens. A high maximum positioning speed of 843 m/s is pointed out within an acousto-optical scanfield of 0.4 $$\text{mm}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mtext>mm</mml:mtext> <mml:mn>2</mml:mn> </mml:msup> </mml:math> by applying positioning frequencies of up to 1 MHz across a distance of 843 $$\upmu \text{m}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>μ</mml:mi> <mml:mtext>m</mml:mtext> </mml:mrow> </mml:math> . Consequently, the hybrid scanning system combines the advantages of optical and mirror-based scanners, enabling a highly dynamic and extremely precise laser beam positioning in a large processing area.