Laser-induced decompression shock development in fused silica

Laser-induced weak shock formation in fused silica is studied using standard wave mechanics and applied to thin-film laser spallation experiments. Due to the negative nonlinear elasticity of fused silica, a laser-induced Gaussian stress pulse evolves into a shock after traveling a certain distance in a fused silica substrate. Experimental observations confirm theoretical predictions of shock development. A decompression shock forms and greatly enhances interfacial failure of a thin film deposited on the substrate. The effects of laser fluence and substrate thickness (attenuation) on shock development are also investigated