纳秒激光烧蚀铝材料的二维数值模拟

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—5 μm.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10⁹ W/cm²量级烧蚀

Two-dimensional numerical simulation of laser-ablation of aluminum material by nanosecond laser pulse

To investigate the interaction between high-power pulsed laser and metal materials,we established a two-dimensional numerical model. The laser-induced two-dimensional temperature distribution was simulated using a finite difference method. From comparison of temperature evolution under different pulse time,spot sizes and energies,it can be seen that the rise of temperature in the initial period is faster than that in the later periods. Isothermal diagram shows that the temperature rising rate is fastest in the center of laser irradiating zone and that the ablation depth is in the range of 1—5 μm. As the laser pulse duration becomes longer,the ablation zone becomes narrower and deeper. As the laser spot diameter increases,the ablation zone becomes wider and shallower. The present numerical results indicate that: (1) the ablation shape and depth sensitively depend on the laser shape,pulse duration and power density, (2) with laser power density in the order of 10⁹ W/cm²,the ablation area is roughly of the orgc of the laser spot. These results are helpful for designing relevant laser parameters in experiments.