In order to study the interaction between a femtosecond laser and a titanium film, the method of combining the two-temperature model and molecular dynamics was used to simulate the ablation and spallation of the titanium film by the femtosecond laser with a wavelength of 800 nm. The spallation of the titanium film was explained from the perspective of the temperature and the stress wave. It is found that the femtosecond laser with a pulse width of 300 fs loads the titanium film, and the ablation threshold is around 0.05 J/cm². The effects of different pulse widths in the range of 100–500 fs and different energy densities in the range of 0.10–0.20 J/cm² on the spallation results of titanium films were also studied. We found that the femtosecond laser with a pulse width of 100 fs promotes the spallation phenomenon to occur more quickly. The surface spallation products of the titanium film were large clusters of atoms when the energy density is 0.10 J/cm², but most of the surface spallation products of the titanium film were single atoms when the energy density is 0.20 J/cm². These indicated that the energy density is an important factor affecting the spallation products of the titanium film. The evolution of maximum electron temperature, electron-lattice equilibrium temperature, and coupling time with pulse width and energy density are also given and analyzed. These results have important reference significance for studying the fracture and damage of titanium, and they help us to understand the mechanism of femtosecond laser processing materials.

中文翻译：

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基于双温度模型和分子动力学的飞秒激光烧蚀和剥落钛膜

为了研究飞秒激光与钛膜之间的相互作用，采用了两种温度模型和分子动力学相结合的方法来模拟波长为800 nm的飞秒激光对钛膜的烧蚀和剥落。从温度和应力波的角度解释了钛膜的散裂。已发现，脉冲宽度为300 fs的飞秒激光器加载了钛膜，并且烧蚀阈值约为0.05 J / cm ²。在100–500 fs范围内的不同脉冲宽度和在0.10–0.20 J / cm ²范围内的不同能量密度的影响还研究了钛膜剥落的结果。我们发现，脉冲宽度为100 fs的飞秒激光器会加速散裂现象的发生。当能量密度为0.10 J / cm ^2时，钛膜的表面散裂产物为大原子簇，而当能量密度为0.20 J / cm ²时，钛膜的大部分表面散裂产物为单原子。。这些表明能量密度是影响钛膜散裂产物的重要因素。还给出并分析了最高电子温度，电子晶格平衡温度以及脉冲宽度和能量密度的耦合时间的演化。这些结果对研究钛的断裂和损伤具有重要的参考意义，有助于我们理解飞秒激光加工材料的机理。