Crack arrest and stress dependence of laser-induced surface damage in fused-silica and borosilicate glass

Results of experiments on stress-inhibited laser-driven crack growth and st ress-delayed laser-damage initiation thresholds in fused silica, borosilica te glass (BK-7), and cleaved bulk silica are presented. A numerical model i s developed to explain the crack arrest in fused silica. Good agreement is obtained between the model and a finite-element code. The crack arrest is d emonstrated to be the result of the breaking of a hoop-stress symmetry that is responsible for crack: propagation in fused silica. (C) 1999 Optical So ciety of America OCIS codes: 140.3440, 140.3330, 160.4670, 140.3390, 240.57 70.