Early dynamics of cavitation bubbles generated during ns laser ablation of submerged targets.

In this study, we observe and study the early evolution of cavitation bubbles generated during pulsed laser ablation of titanium targets in different liquid environments utilizing a high-resolution stroboscopic shadowgraphy system. A hydrodynamic model is proposed to calculate the early pressure changes within the bubble and in the surrounding fluid. Our results show that the cavitation bubble is a low-pressure region that is bounded by a high-pressure fluid lamina after the incipient stage, and its evolution is primarily affected by the liquid density. Moreover, the initial bubble pressure increases substantially in high viscosity liquids. This work illuminates how the liquid properties affect the early bubble dynamics and is a step towards a deeper understanding of laser-materials interactions in liquid environments.