摘要
激光诱导薄膜损伤过程中,雪崩离化(AI)和多光子离化(MPI)的性质和作用到目前仍然存在争议。基于STUART等人的电子密度演化方程,运用数值模拟方法,研究了脉宽为τ∈[0.01,5]ps范围内单脉冲激光作用下熔融石英薄膜中电子密度演化过程;讨论了初始电子密度、激光脉冲宽度对阈值功率密度和阈值能量的影响;分析了初始电子密度、激光脉冲宽度对多光子离化及雪崩离化的影响。研究结果表明,在所研究的脉宽范围内,对于熔融石英光学薄膜、飞秒激光诱导损伤以雪崩离化为主导,多光子离化的影响随着脉宽的降低而增强,雪崩离化所需种子电子主要来源于多光子离化。
There exists some controversial between the nature of the avalanche ionization （AI） and the role of the multi - photon ionization （MPI）. Based on Stuart et al. ＇s electron density evolution equation ,the electron density evolution process in fused sili- ca film irradiated by short - pulse laser for τ∈[0.01,5]ps were studied by means of numerical method. The effects of initial electron density Ni and laser pulse width T on laser threshold intensity lth and damage threshold fluence. Fth were analyzed respectively. The effects of Ni and τ on MPI and AI were also discussed. The results show that, for fused silica film, the laser - induced damage is dominated by AI, the effect of MPI increases with the decrease of pulse width τ. The seed electron generation needed in AL comes chiefly from MPI.
出处
《武汉理工大学学报（信息与管理工程版）》
CAS
2008年第6期905-908,共4页
Journal of Wuhan University of Technology：Information & Management Engineering
基金
国家自然科学基金资助项目(60708004)
国家自然科学基金资助项目(10804090)
关键词
激光诱导损伤
多光子离化
雪崩离化
初始电子密度
损伤阈值能量
laser - induced damage
multi - photon ionization
avalanche ionization
initial electron density
damage threshold fluence
