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为了探索纳秒脉冲强激光与材料的相互作用机理,建立了二维数值模型,利用有限差分法对纳秒激光脉冲烧蚀金属铝的温度场进行了数值模拟.通过对比不同脉宽、光斑和能量下激光引起的温度场随时间的演化,发现脉冲的前期温度升高比后期快.等温图显示中心温度升高最快,烧蚀轮廓与激光束形状相似,烧蚀深度达1—5μm.脉宽越长,烧蚀越窄和越深,光斑越大,烧蚀越宽和越浅.数值研究表明,1)激光的脉冲形状、脉宽和功率密度直接影响烧蚀的形状和深度;2)激光功率密度在109W/cm2量级烧蚀面近似为光斑大小.这些结果对于实验上设计激光控制参数有一定指导作用。
In order to explore the mechanism of nanosecond pulsed laser interaction with materials, a two-dimensional numerical model was established and the finite difference method was used to simulate the temperature field of nanosecond pulsed ablation metal aluminum. By comparing different pulse width, spot and The evolution of the temperature field caused by the laser energy over time shows that the temperature of the pre-pulse rises faster than that of the latter, and the isothermal image shows the fastest increase of the center temperature. The ablation profile is similar to that of the laser beam. The longer the pulse width, the narrower and deeper ablation, the larger the spot size, the wider and shallower the ablation.The numerical results show that 1) the pulse shape, pulse width and power density of laser directly affect the shape and depth of ablation; 2) Laser power density at the order of 109W / cm2 Ablation surface approximates the size of the spot.These results provide some guidance for the experimental design of laser control parameters.