Ultrafast stamping by combination of synchronized galvanometer scanning with DOE's or SLM (Conference Presentation)

Abstract

The upscaling of laser micromachining processes with ultrashort pulses is limited due to heat accumulation and shielding effects. Multibeam scanning represents one of the strategies to overcome this drawback. It is in general realized by combining a diffractive beam splitter with a galvanometer scanner. A full synchronization with the laser repetition rate offers new possibilities with minimum thermal impact. We will demonstrate this by means of a multipulse-drilling on the fly process with a regular 5x5 spot pattern having a spot to spot spacing of 160µm. With a constant speed (synchronized to the laser) this pattern can be moved by exactly this spacing between two laser pulses. At a repetition rate of 100 kHz and an average power of 16 W we were able to drill more than 1'500 holes/s in a 10µm thick steel foil without any thermal impact. In a next step we will extend this technology with an SLM to different periodic patterns.