Study on damage characteristics of fused silica glass induced by plasma shock wave with finite element method

Abstract

The damage problem of fused silica has always been one of the bottlenecks limiting the energy output of the high-power laser system. For optical components, the ionization breakdown by laser is the main factor causing damage, especially for laser plasma shock waves, which can cause large-scale fracture damage in fused silica. In this paper, the fused silica damage experiment was induced by a nanosecond laser, and the damage morphology of fused silica in the thickness range of 0.8-5.0 mm was obtained under the action of a 1-20 pulse. The damage size of fused silica decreases as the thickness of the material increases until the thickness of the material is greater than, or equal to, 1.4 mm. On the basis of theoretical analysis of a plasma shock wave, the coupling and transmission of shock wave in fused silica were studied by finite element method, and the magnitude and direction distribution of stress were obtained. By analyzing the fracture characteristics and Raman spectra of the three damaged regions of fused silica, the structural differences of a range of damage regions are analyzed, and the relationship between the macroscopic damage of fused silica and the microstructure is explained. The research results can provide a reference for understanding the characteristics and mechanism of damage characteristics induced by laser plasma shock wave.