Speaker: Inka Manek-Hönninger (University of Bordeaux, CNRS-CELIA)

Femtosecond laser materials processing in the GHz-burst mode has attracted much attention in the last few years [1,2], especially for top-down percussion drilling in dielectrics thanks to the outstanding machining quality of the holes [3]. In this contribution, I will first give an introduction to femtosecond laser GHz-burst processing. Then, I will show some results on glass drilling including pump-probe shadowgraphy with a temporally shaped femtosecond laser beam operating in the GHz-burst regime [4]. The pump laser source is a 100-W average power industrial femtosecond laser system emitting at a wavelength of 1030 nm that can be operated in the single pulse, in MHz-burst and in GHz-burst regime. Pump-probe imaging in the burst regime in far from being trivial. Indeed, a second laser is needed operating in single pulse regime for the probe beam. In order to perfectly synchronize the probe beam with the pump beam, a portion of the pump oscillator was injected into a Yuja-based amplifier from Amplitude. Thanks to this setup, we were able to measure the luminescence time of the plume in both burst regimes and to compare it to the regime of standard repetitive single pulses. Moreover, we monitored the plume behavior during the drilling process of through holes revealing interesting information about the drilling process dynamics, its limits and solutions to overcome them.

References

1. C. Kerse, H. Kalaycoglu, P. Elahi, B. Cetin, D. Kesim, et al., Ablation-cooled material removal with ultrafast bursts of pulses, Nature 537, 84–88 (2016); https://doi.org/10.1038/nature18619
2. P. Elahi, O. Akçaalan, C. Ertek, K. Eken, F.O. Ilday, et al., High power Yb-based all-fiber laser delivering 300 fs pulses for high speed ablation cooled material removal, Opt. Lett. 43, 535-538 (2018); https://doi.org/10.1364/OL.43.000535
3. P. Balage, J. Lopez, G. Bonamis, C. Hönninger, I. Manek-Hönninger, Crack-free high-aspect ratio holes in glasses by top-down percussion drilling with infrared femtosecond laser GHz-bursts, Int. J. Extrem. Manuf. 5, 015002 (2023); https://doi.org/10.1088/2631-7990/acaa14
4. P. Balage, T. Guilberteau, M. Lafargue, G. Bonamis, C. Hönninger, J. Lopez, I. Manek‐Hönninger, „Pump-Probe Imaging of Ultrafast Percussion Drilling of Glass in Single Pulse, MHz- and GHz-Burst Regimes”, Adv. Mater. Interfaces, 2400853 (2025); https://doi.org/10.1002/admi.202400853