纳秒激光烧蚀铝等离子体羽流膨胀特性实验

Experiment research on plasma plume expansion induced by nanosecond laser ablation Al

为研究纳秒激光烧蚀铝产生的等离子体羽流膨胀速度特性,采用波长1 064 nm,脉宽10 ns,功率密度～1.3×108W/cm2YAG激光器烧蚀铝靶材,得到100 ns内铝等离子体在～260 Pa背景压力下的膨胀照片。通过对拍摄照片数据处理得到,等离子体羽流膨胀速度相对于靶面法线方向大致呈轴对称分布,且高斯函数可以很好地描述烧蚀等离子体羽流速度分布。

In order to investigate the plume dynamic property ablated by nanosecond laser ablation, a systematic investigation of plasma plume expansion, generated by a Q - switched Nd - YAG at 1 064 nm with laser power density - 1.3 ×10^8 W/cm2 on Al target, was done for a residual pressure of -260 Pa using a fast gated intensi- fied CCD camera with a gate width of 3 ns to capture the images. The expansion studies were done up to a distance of about 5 mm from the target surface. The high magnification near - target imaging results and digital image pro- cessing technique determine the plasma edge contours. The results show that the plume expansion is axisymmetrical distributed with respectively normal to the target surface. In addition, the fitting function based on the theory of Sedov can depict position distribution of the plasma plume well.