超短脉冲激光辐照下金属薄膜的热行为

Thermal Behavior of Thin Metal Films Irradiated by Ultra-Short Pulse Laser

对双温模型的重要热学参量电子热容、电子弛豫时间、电子热导率进行量子化处理,使双温模型能适用于自由电子温度比较高的情况.利用前向差分算法,数值求解了电子-晶格双温双曲两步热传导模型,所得的结果更接近实验值.经过分析得出:1)薄膜前表面自由电子温度达到最大值的时间约为0.27 ps,得到的损伤阈值与实验值符合较好.2)电子热容对电子温升规律影响非常大.电子热导率对自由电子温升规律也有较大的影响.3)在趋肤层内自由电子温升非常快,不同厚度自由电子温度达到最大值所需的时间延迟不明显.趋肤层以下自由电子温度升高较慢,不同厚度自由电子达到最大值所需的时间延迟明显.

The importent parameters of two-temperature model with high electron temperature are studied by using full-run quantum treatment, including the electron heat capacity, electron relaxation time and electron conductivity . A dual-hyperbolic two temperature model is solved numerically using an accurate and stabile forward-difference scheme, in which one kind of artificial viscosities and adaptive time steps method are introduced. The conclusions are. 1） Electron temperatures of front surface rise to the maximum temperature in 0.27 ps. This model predicts the damage thresholds more accurately compared with published experimental results. 2） electron heat capacity have a great inflence on the law of temperature rise. ,Electron conductivity also has a lesser inflence. 3） The temperature of free electron gas rises more quickly in optical depth. In difference thickness, the time of free electron gas reaching the maximum temperature not obvious delay. Under optical depth temperature of free electron gas rises