Femtosecond laser ablation by bibursts in the MHz and GHz pulse repetition rates

Here, to the best of our knowledge, for the first time we report an in-depth experimental study of high ultrafast laser ablation efficiency for processing of copper and steel with single-pulses, MHz, GHz, and burst-in-the-burst (biburst) regimes. The comparison of burst, biburst, and single-pulse ablation efficiencies was performed for beam-size-optimised regimes, showing the real advantages and disadvantages of milling and drilling processing approaches. Highly efficient ultrashort pulse laser processing was achieved for similar to 1 mu m optical wavelength: 8.8 mu m(3)/mu J for copper drilling, 5.6 mu m(3)/mu J for copper milling, and 6.9 mu m(3)/mu J for steel milling. We believe that the huge experimental data collected in this study will serve well for the better understanding of laser burst-matter interaction and theoretical modelling. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study presents an in-depth experimental investigation of high ultrafast laser ablation efficiency for copper and steel processing, comparing different modes and showing the advantages and disadvantages of milling and drilling approaches. The results demonstrate that copper drilling has the highest efficiency, followed by steel milling, under the condition of approximately 1 micron optical wavelength. The extensive experimental data collected in this study will contribute to a better understanding of laser burst-matter interaction and theoretical modeling.