激光聚焦熔石英表面产生击穿的热力学效应分析

Thermodynamic effects analysis on the breakdown of the silica surface induced by focused laser pulse

利用纳秒激光脉冲辐照熔石英玻璃产生击穿的方法,仔细观测了熔石英表面损伤的微观形貌,并基于激光击穿过程的热力学效应对损伤机理进行了研究。研究表明:激光脉冲能量的沉积主要是基于激光等离子体的逆韧致吸收效应,高温高压等离子体是导致熔石英玻璃损伤的主要因素;熔石英玻璃在击穿过程中伴随着温度升高、材料熔化、气化以及电离等过程,这些效应使得玻璃发生相变以及断裂,而冲击波效应会使得相变材料发生去除辐照区周围玻璃发生剥离而形成大范围的坑状破坏点。

The nanosecond laser pulse has been used to induce breakdown on the fused silica glass, furthermore,the micro-morphology of damaged fused silica glass has been observed carefully, and the damage mechanism has been studied based on thermodynamic effects. The result shows： the laser pulse energy deposition is mainly due to laser-plasma inverse bremsstrahlung absorption effect, high pressure and high temperature plasma is the main factor for the destruction of fused silica glass; The breakdown of fused silica glass involves the rise of breakdown temperature, the melting the material, vaporization and ionization and so on, which can make phase transition and fracture of glass, and the shock wave effect make the phase change material removed and the glass surrounding the irradiation can be peeled off, the pit-shaped damage is formed.