Effects of pressure on the electronic and optical properties of defect-free and defect-containing fused silica: A first-principles study

Fused silica is a widely used optical material in high-power solid-state laser systems. The electronic and optical properties of fused silica are affected by point defects and stress in the material. In this paper, the electronic and optical properties of fused silica are calculated using the first-principles method. The study found that the band gap of defect-free fused silica material gradually decreases as the pressure increases. When the fused silica material contains oxygen vacancy or silicon vacancy defects, the band gap size is not proportional to pressure. During the elastic deformation stage, low strain and high strain cause a sudden change in the band gap size of defect-containing fused silica. This paper reveals the mechanism of the influence of pressure on the band gap and optical properties of defect-free and defect-containing fused silica materials from the perspective of micro-stress.