UV-laser-induced densification of fused silica: a molecular dynamics study

Classical molecular dynamics simulations have been performed to study the UV-laser-induced densification in fused silica. Relationships between induced densification and absorbed laser fluence under different laser durations are established. We have also studied the effects of laser irradiation on the radial distribution functions, static structure factor, bond-angle distributions, ring-size distribution, and elastic constants of fused silica. While the Si–O bond length is little affected by laser irradiation, the lengths of O–O and Si–Si and bond-angle distributions of ∠Si–O–Si and ∠O–Si–O are undergoing larger changes. The number of dominant 6-member rings decreases after laser irradiation, and that of rings of other sizes increases. Young’s modulus, bulk modulus, and Lamé constant of fused silica increase rapidly with increasing density.