超短脉冲激光对无机硅材料的损伤

通过控制作用于材料表面的激光能量和脉冲数量,实验研究了800nm,50fs,1kHz激光作用下融石英玻璃和硅片的破坏机制和损伤规律,计算了材料的损伤阈值与脉冲能量以及脉冲数量的依赖关系,并采用简化的理论模型计算了熔石英玻璃材料的损伤阈值与激光脉宽以及光子能量之间的依赖关系。对这两种无机硅材料在飞秒脉冲作用后的微区结构改变进行了扫描电子显微镜(SEM)测试,研究了其形貌特征。结果表明,硅片是由缺陷中的导带电子作为种子电子引发雪崩电离导致材料损伤,而熔石英玻璃是由多光子电离激发出导带电子引发雪崩电离导致材料损伤。

Ultra-Short Pulsed Laser-Induced Damage in Inorganic Silicon Materials

The femtosecond laser (800 nm, 50 fs, 1 kHz) induced damages in Si wafer and fused silica are studied by experiments. The morphologies of structural changes in the two inorganic silicon materials have been investigated by means of charge coupled device (CCD) camera and scanning electron microscopy (SEM). Furthermore, the relationship of damage threshold to laser pulse duration and photon energy is studied. The main process during laser-induced damage in Si wafer is that avalanche ionization which is seeded by electrons due to defects, while that avalanche ionization is seeded by electrons excited by multi-photon ionization is the main process during laser-induced damage in fused silica. The energy deposition is initiated by multiphoton ionization rather than impurities or defects to start an electron avalanche in transparent materials.