纳秒激光诱导透射元件粒子喷射的分布特征

光学元件在高能量激光辐照下将发生激光损伤，损伤过程伴随着材料破裂、结构崩塌和粒子喷射，而向外喷出的粒子将影响周围光学元件的激光损伤性能。搭建了双光束泵浦探测成像系统，获得了激光诱导透射元件粒子喷射的瞬态图像，并根据粒子接收板的统计数据，获得了喷射粒子的空间分布、粒子尺寸和出射角度特征。同时，针对不同激光能量、不同的粒子接收距离以及真空度，对喷射粒子分布的影响因素进行了研究；此外，还结合能谱仪对激光诱导金属膜喷发后的分布规律、不同金属元素在大气与真空环境中的喷射行为进行了对比分析。实验结果表明:透射元件在激光作用下喷发出微米尺寸的粒子形态，金属膜的喷发主要以原子态或熔融液滴为主；粒子在最终接收板上的分布特征主要受初始条件的影响，而真空环境影响相对较小；不同薄膜制备工艺对金属膜的喷发特征影响较为明显。

Distribution characteristic of ejected particles from transmissive element induced by nanosecond laser

Optical instrument will be damaged when irradiated by high-energy laser. The damage process is accompanied by material fracture, structural collapse and particle ejecting, and the particles emitted will affect the performance of surrounding optical instruments. In this paper, a dual-beam pump-probe imaging system was built to obtain a transient image of the particles ejected form transmissive element induced by nanosecond laser. A particle receiving plate was placed behind the sample, so that the spatial distribution of the particles as well as the size and angular characteristics were analyzed. Then, the effects of different laser energies, different particle receiving distances and vacuum environment on the particle distribution were studied. In addition, combined with EDS spectrum detection technique, the characteristic of particles induced in the metal film was investigated. Also, the differences between different kinds of metal film and the influence of the vacuum environment were studied. The results show that the transmissive substrate emits micron-sized particles under laser induction, while atomic state particles or molten droplets from metal film. The distribution characteristics of the particles on the final receiving plate are mainly affected by the initial conditions. There is little change in the vacuum within a few pascals, and different metal films are also significantly affected by their own properties.....