Design of multi-beam optics for high throughput parallel processing

The utilization of ultrashort pulsed laser radiation enables the precise generation of microstructures and the processing of a wide variety of materials. However, for massive parallel processing, the raw intensity distribution of the beam emitted by the laser source usually has to be transformed into an arrangement of multiple laser beams with specific intensity distributions. Here, sophisticated, application-adapted optical systems serve as a key technology. This paper gives an overview of the optical design fundamentals of multi-beam optics. It also investigates the causes for one of the main challenges in the use of multi-beam optical systems: the distortion of the spot-array on the work piece. The distortion leads to individual spot position errors and can heavily limit the processing accuracy. Finally, active and passive concepts and technologies to reduce or eliminate distortion in multi-beam systems are presented.