不同激光参数与真空中铝的冲量耦合

Impulse coupling to aluminum in vacuum with different laser parameters

冲量耦合是高功率激光烧蚀材料过程中的一个重要物理现象,成为许多应用研究的物理基础,而激光对材料的冲量耦合大小直接与所采用的激光辐照参数密切相关。在真空中,冲量耦合仅由蒸发波决定,反冲压力存在时间主要取决于激光脉冲维持时间,因而冲量计算须考虑材料的非定常气化过程。利用非定常透明蒸汽模型,研究了真空条件下不同波长和不同脉宽激光与铝靶作用时的冲量耦合系数及随入射激光功率密度的变化关系,计算结果与实验结果符合较好。

Laser induced impulse coupling is one of the important phenomena in laser ablation to materials and leads to many applications. The amplitude of impulse coupling coetticient is varied with laser parameters on target. As the timescale of repulse pressure is mainly determined by laser duration, laser produced impulse coupling in vacuum is only caused by vaporization contributions, so unsteady vaporization have to be considered in making some calculations on laser induced momentum. The dependence of impulse coupling coefficient to aluminum in vacuum vs. incident laser intensity with different wavelength and pulsewidth are studied by unsteady transparent vapor model. Good agreement between theoretical results and experimental measurements has been achieved.