Pulse laser ablation at water–air interface
Pulse laser ablation at water–air interface
复制标题
DOI：
10.1007/s00339-010-5696-y
复制
发表时间：
2010-04
期刊：
影响因子：
--
通讯作者：
Y. Utsunomiya;T. Kajiwara;T. Nishiyama;K. Nagayama;S. Kubota
中科院分区：
文献类型：
--
作者：
Y. Utsunomiya;T. Kajiwara;T. Nishiyama;K. Nagayama;S. Kubota
研究了一种新的脉冲激光烧蚀液体表面层的现象，这种现象是由于两种材料的折射率不同而引起的。本研究的动机是我们以前的研究，这表明，激光烧蚀可以发生在透明材料和气体或液体介质之间的界面时，激光脉冲通过透明材料聚焦。在这种情况下，烧蚀阈值注量显著降低。在本研究中，在水和空气中进行实验，以确认这一现象的两种流体介质具有不同的折射率的组合。用脉冲激光阴影法详细观察了这种现象。用脉宽为10 ns的Nd：YAG脉冲激光作为光源，用高分辨率胶片记录了这一现象。用波长为1064 nm的Nd：YAG激光脉冲聚焦后，在液体表面层产生激光烧蚀现象，随后液体表面发生飞溅，形成一个多韧带的液体射流。在典型情况下，液体射流延伸速度为约1000 m/s。由于韧带尖端的快速雾化，液体射流急剧减速。液体射流现象被发现依赖于脉冲激光参数，如液体表面上的激光能量密度，激光能量，和激光束图案。用于产生液体射流的阈值激光能量密度为20 J/cm 2。在固定激光能量密度的情况下，通过增加入射激光能量，激光聚焦面积增加，这最终导致等离子体柱的尺寸增加。激光能量越大，射流尺寸越大，时间行为越长。激光束的图案被发现有显着的液体射流的速度，形状和历史的影响。
We studied a new pulse laser ablation phenomenon on a liquid surface layer, which is caused by the difference between the refractive indices of the two materials involved. The present study was motivated by our previous study, which showed that laser ablation can occur at the interface between a transparent material and a gas or liquid medium when the laser pulse is focused through the transparent material. In this case, the ablation threshold fluence is reduced remarkably. In the present study, experiments were conducted in water and air in order to confirm this phenomenon for a combination of two fluid media with different refractive indices. This phenomenon was observed in detail by pulse laser shadowgraphy. A high-resolution film was used to record the phenomenon with a Nd:YAG pulse laser with 10-ns duration as a light source. The laser ablation phenomenon on the liquid surface layer caused by a focused Nd:YAG laser pulse with 1064-nm wavelength was found to be followed by the splashing of the liquid surface, inducing a liquid jet with many ligaments. The liquid jet extension velocity was around 1000 m/s in a typical case. The liquid jet decelerated drastically due to rapid atomization at the tips of the ligaments. The liquid jet phenomenon was found to depend on the pulse laser parameters such as the laser fluence on the liquid surface, laser energy, and laser beam pattern. The threshold laser fluence for the generation of a liquid jet was 20 J/cm2. By increasing the incident laser energy with a fixed laser fluence, the laser focused area increased, which eventually led to an increase in the size of the plasma column. The larger the laser energy, the larger the jet size and the longer the temporal behavior. The laser beam pattern was found to have significant effects on the liquid jet’s velocity, shape, and history.