Dynamic characterization of plasma and combustion wave interactions during millisecond-nanosecond combined laser-induced enhanced damage on fused silica

Fused silica, which is widely used in optical systems, limits the load capacity of the optical system when it is damaged by laser irradiation. In this paper, a combined millisecond-nanosecond pulsed laser induced triple combustion wave dynamics model for fused silica generation is developed. The relationship between pulse delay and the dynamic propagation of plasma and combustion waves induced by combined laser-induced fused silica was studied from three aspects: theory, simulation, and experiment. The results show that the energy deposition of the nanosecond laser injects energy into the dilute plasma, which increases the speed of the double-burning wave to form a triple-burning wave. In addition, it was found that the combined effect of viscous shear between the plasma plume and the air exacerbates the degree of imbalance in the Knudsen layer instantaneously releasing pressure and increasing the complexity of plasma and combustion wave propagation, recoil pressure produces a more complex crack network on the fused silica surface. The results provide a better understanding of the propagation properties of plasma and triple-burning waves during combined millisecond-nanosecond induced fused silica damage.