等离子体吸收对飞秒激光烧蚀绝缘材料的影响

Absorption Affection of Plasma to Femtosecond Laser-induced Breakdown Threshold in Dielectric

以自由电子运动的速率方程模型为基础,研究了飞秒脉冲激光对绝缘材料的烧蚀机理,考虑了等离子体对激光能量的吸收效应,建立了激光强度与电子数密度及等离子体吸收系数三者相互耦合的数学模型,计算出飞秒激光烧蚀绝缘材料时的烧蚀阈值,分析了考虑等离子体吸收效应对烧蚀阈值的影响,通过与不考虑等离子体吸收所得结果相比较说明该效应是影响烧蚀阈值的一个重要因素。

Based on rate equation of electron evolution, the mechanisms of ultra-short pulse laser induced breakdown threshold in dielectric is studied. The plasma＇s absorption to the laser energy is taken into account. The model including laser intensity, the coefficient of the plasma＇s absorption and the electron density is set up and the fluenca of ultra-short pulse laser-induced breakdown threshold is calculated. The model results show the identity with the experimental results. The affection to the fluence with plasma＇s absorption is gotten and analyzed, it is concluded that this element can not be ignored by comparing the results with or without plasma＇s absorption.