飞秒激光照射金箔的分子动力学模拟

采用耦合双温度模型的分子动力学方法对飞秒激光照射金箔的传热过程进行了模拟研究，利用序参数法对固相原子和液相原子进行了区分并获取了固液界面的位置及温度随时间的变化规律。在此基础上探究了激光能流密度对熔化过程的影响。结果表明，随着激光能量的吸收及传递，金原子逐渐由面心立方的规则排列变为无序的松散排列，固液界面随时间逐步向金箔底部移动，金箔体积不断变大。当激光能流密度较小时，金箔未完全熔化，且熔化发生时刻较晚。激光能流密度越大，金箔熔化越早越快，熔化深度也越大，固液界面处温度也越高。

Abstract

The heat transfer process of gold foils irradiated by a femtosecond laser pulse is simulated and studied by the molecular dynamics method combined with the two-temperature model. A local order parameter is adopted to distinguish the solid and liquid phase atoms and the changing laws of the location and temperature of the solid-liquid interface versus time are obtained. On this basis, the effect of laser energy flux density on the melting process is investigated. It is shown that, with the absorption and transfer of laser energy, the lattice arrangement of Au atoms changes gradually from a regular and face-centered-cubic structure into an irregular and loosely arranged one. As time goes by, the solid-liquid interface gradually moves towards the bottom of the gold foil, and the foil volume also expands gradually. When the laser energy flux density is low, the gold foil does not melt completely and the melting is delayed. In contrast, the higher the laser energy flux density is, the melting occurs earlier and more rapidly, the melting depth is larger, and the interfacial temperature is higher.

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闫焱, 李凌. 飞秒激光照射金箔的分子动力学模拟[J]. 光学学报, 2016, 36(8): 0814001. Yan Yan, Li Ling. Molecular Dynamics Simulation of Femtosecond Laser irradiating Gold Foils[J]. Acta Optica Sinica, 2016, 36(8): 0814001.

飞秒激光照射金箔的分子动力学模拟

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