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

Here, to the best of our knowledge, for first time we report in-depth experimental study high ultrafast laser ablation efficiency processing copper and steel with single-pulses, MHz-, GHz- burst in (biburst) regime. The comparison burst, biburst, single-pulse efficiencies was performed beam-size-optimised regimes, showing real advantages disadvantages milling drilling approaches. Highly-efficient ultrashort pulse achieved ~1 um optical wavelength: 8.8 um3/uJ drilling, 5.6 milling, 6.9 milling. We believe that huge data collected this will serve well better understanding burst-matter interaction theoretical modelling.