Ejection and dispersion of particles in damage growth of fused silica induced by high-fluence centimeter scale aperture laser beam.

Abstract

In this paper, we report an investigation into the dynamics of laser-induced particle sputtering on the rear surface of fused silica at high-fluence laser systems. Using time-resolved pump-probe and continuous imaging techniques, we capture the entire sputtering process over a broader timescale. The morphology, kinematics, and their correlation with damage growth are analyzed through microscopic imaging. The results indicate that thermodynamic effects govern particle ejection, with air viscosity influencing their trajectories. An empirical fluid mechanics-based formula is proposed to predict sputter distance, showing that larger particles with higher initial velocity travel farther. As laser fluence increases, the velocity of smaller particles grows, while the velocity of larger particles and sputtering volume are linked to the growth of the damaged area.