When thermal damages have to be avoided and, simultaneously, a high throughput is required, new strategies have to be developed. A new approach is the use of Diffractive Optical Elements (DOEs) for massive process parallelization of laser micro machining applications. For many applications, the average power of the laser source exceeds, by far, the applied power for an optimal process result.
This paper presents an increase of productivity by a factor of more than 5 due to a distribution of laser power over multiple laser spots. Two exemplary applications for damage-free ablation are processing of metallic compressor blades for fluidic purposes as well as crystalline Silicon solar cells for photovoltaic panels. The surface structure on compressor blades, so called Riblets, needs a precise topography which will be gained only by ultra-short laser pulses. The same requirements can be observed within the processing of high quality crystalline Silicon solar cells. In respect to industrial requirements for these applications, the throughput gain in micro processing and increased process efficiency is exemplarily demonstrated in this paper.
A study of the ablation effects when using multi-spot DOE in comparison to single spots is investigated and discussed. A theoretical analysis of the optimal set of parameters for efficient parallel processing with high- power lasers completes this paper.