Nanosecond laser ablation of a metallic glass in water: a high time-resolved imaging study

We use a state-of-the-art, ultrafast camera to probe the nanosecond pulse laser ablation of a metallic glass target in water. The laser-induced plasma of metallic glass is captured for the first time. We further observe a series of shock waves in water and the cavitation bubble on the target surface. The shock waves inherit the rapid expansion of the plasma, satisfying the momentum conservation. But the cavitation bubble stems from the nucleation of the surrounding water due to the heating of the plasma. We find that the bubble growth deviates from the Rayleigh-Plesset theory. The primary reason for this deviation is the effect of ablation products due to the temporal overlap between the explosive boiling and the bubble dynamics. Our findings provide a fundamental understanding of underwater laser ablation of metallic glasses, which is an important step to forward such ablation-related applications.