Automated free-space beam delivery system for ultrafast laser beams in the kW regime

Abstract

In contrast to cw laser beams, the beam delivery of ultrafast laser beams with high average power or high pulse energies using optical fibers is still a challenge. In this paper, we present a free-space delivery and distribution system, which is able to deliver ultrafast laser beams with an average power of up to 5 kW and pulse energies of up to 5 mJ. This system is designed for automated switching between up to three laser sources and four processing stations with state of the art safety measures. Currently it is in use at the IFSW, with one kW class ultrafast laser source and three processing stations with a distance of up to 15 m from the laser source. Due to its active beam stabilization, high precision processes are possible, like Direct Laser Interference Patterning with structure periods below 1 µm, OCT based ablation control or micro drilling.