Photoacoustically assisted material ejection from fused SiO₂ following UV nanosecond laser ablation

When an ultraviolet nanosecond laser focuses on the rear surface of a fused SiO₂ sample through its front surface, two internal shock waves (SWs) generating from the rear surface propagate toward the front surface. These SWs are derived as the consequence of different physical processes giving rise to ablation particles. They will induce micro-ejection particles from the existing micro-crater sculpted by the laser at the front surface, if their intensities are higher than the yield strength of the material. Atomistic simulations reveal the formation mechanism of shock-induced ejection from the ablated defects. Photoacoustically assisted material ejection has been theoretically and experimentally verified.