超短脉冲激光辐照金属薄膜温升效应的模拟研究

 考虑到材料的质量热容、热导率、驰豫时间等热力学参数随温度非线性变化因素的影响，利用具有人工粘性的、自适应时间步长的前向差分算法，数值求解了电子-晶格双温双曲两步热传导模型，讨论了厚度为50 nm的金膜在0.1 ps脉冲激光辐照下的温升规律。数值结果表明：薄膜前表面自由电子的温度在大约0.27 ps时达到最大值，不同厚度上自由电子达到温度平衡所需的时间大约为1.6 ps，而薄膜温度在整个厚度上达到平衡所需时间为60 ps左右。由电子温度及其温度梯度引起的热电子崩力很可能是造成材料破坏的一个主要因素。

Simulation study on thermal effect on metal films irradiated by ultra-short pulse laser

Using the model of dual-hyperbolic two temperature,taking the gold film as example,the temperature effects on heat capacity,thermal conductivity and relaxation time have been studied with an accuracy and stability forward-difference scheme,to which one kind of artificial viscosities and adaptive time steps method is introduced.The primary researches in this paper are on the thermal response of 50 nm gold film irradiated by 0.1 ps laser pulse.The numerical results indicate that after having been heated for 0.27 ps the maximum electron temperature at the front surface occurs,after about 1.6 ps the temperature equilibration time of all electrons is achieved,while that of the whole film is got after about 60 ps.Hot-electron blast force damage could be a dominant mechanism in ultra-short laser-material ablation,which is proportional to the product of the temperature and the temperature gradient in the electron gas.