High power ultrashort pulse laser processing using a flexible multibeam approach

Abstract

Laser ablation is used as a machining process for several industrial applications. Especially ultrashort pulse laser sources with pulse durations below 10 ps have gained increasing interest as they enable processing of almost any material with very high precision and negligible thermal load for the processed workpiece. However, these precise processes are comparable slow and the limited productivity is the major drawback of this processing technology. Although ultrafast lasers with more and more average output power are developed, such powers cannot be directly transferred into productive high quality processing results, because thermal load increases and cancels out the advantages of ultrafast laser processing. Approaches like fast scanning technologies or beam splitting allow for the use of high average power in principle but decrease flexibility or process efficiency on the other hand. We report on a approach where a matrix of multiple beams is generated out of one beam and all of these beamlets can be switched on and off individually. This scalable approach enables the processing of arbitrary surface structures with high process quality and efficiency. The system in development will be able to use 1 kW average output power with fs pulse duration to significantly decrease processing times for industrial structuring applications. In this report, the approach is presented and the challenges with respect to the design of the corresponding processing optics are described and discussed. Preliminary results about the solutions for the faced issues are presented.