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本文报道了利用超快时间分辨阴影图方法对飞秒激光脉冲烧蚀金属铝的动态物理过程的研究。实验发现在50fs泵浦脉冲轰击靶表面后存在热与非热的烧蚀机制,证明在40J/cm2激光流量下超快激光烧蚀过程是一个涉及到多种不同物理和力学作用的复杂过程。在1—1.5ns延迟的阴影图中清晰地看到被烧蚀物质即将发生相位爆炸时产生的衍射条纹,在4ns和9ns延迟的阴影图中观察到喷射物内部存在由于极强热弹力波的出现而引起的间歇性物质喷射。在硅和玻璃的烧蚀实验中也观察到了类似的物理过程。但对于玻璃样品,没有观察到间歇性物质喷射现象。
This paper reports the study of the dynamic physical process of femtosecond laser ablation of aluminum by ultra-fast time-resolved shadow mapping. It was found that there was a thermal and non-thermal ablation mechanism after the 50fs pump pulse bombarded the target surface. It was proved that the ultra-fast laser ablation process at 40J / cm2 laser flow is a complicated process involving many different physical and mechanical effects. Diffraction fringes occurred immediately before phase ablation of the ablated material were clearly seen in the shadow of a 1-1.5 ns delay and were observed in the shaded 4 ns and 9 ns delayed images due to the very strong thermo-elastic waves Occurrence of intermittent material jet. A similar physical process was observed in the ablation experiments of silicon and glass. However, no intermittent material injection phenomenon was observed for the glass samples.