高能飞秒激光烧蚀金靶材的动态热导率影响研究

Effect of Electronic Thermal Conductivity on Properties of Gold Target Material of Femtosecond Laser Ablation

讨论了高能飞秒激光烧蚀金属金靶材过程中电子热导率对激光烧蚀性质的影响。由于电子热容量,电声耦合系数及电子热导率等热物理参数对能够表征飞秒激光烧蚀性质的电子最高温度,电声耦合时间及电声耦合温度都有一定影响,且这3个热物理参数都为电子温度或电子温度及晶格温度相关的表达式,为了更清楚了解电子热导率对飞秒激光烧蚀性质的影响,将电子热容量及电声耦合系数在合理范围内分别取常数值,而对电子热导率在合理范围内按等差规律分别取3个常系数值,通过在一维双温模型的基础上变化电子热导率常系数值模拟飞秒激光烧蚀金属靶材的热传输演化过程,详细研究了电子热导率对飞秒激光烧蚀金靶材性质的影响。结果表明:电子热导率对金靶材表面电子最高温度,电声耦合时间及电声耦合温度都有不同程度影响。由于电子热导率实质在靶材表面电子达到最高温度后反映的是电子亚系统中电子释放能量速率快慢,因此导致电子热导率对电声耦合温度的影响最为显著。

The influence of electronic thermal conductivity on properties of the femtosecond laser ablation of gold was studied. Because the electron heat capacity, electron-phonon coupling coefficient and electronic thermal conductivity and other thermal physical parameters had influence on the maximum temperature, electron-phonon coupling time and electron-phonon coupling temperature, which characterized the properties of femtosecond pulsed laser ablation. In addition, the physical parameters were expressions of electron temperature or electron temperature and lattice temperature. In order to better understand the influence of electronic thermal conductivity on properties in femtosecond laser ablation, electronic heat capacity and electron-phonon coupling coefficient were taken a reasonable constant value, re- spectively, while the electronic thermal conductivity was taken three constant values within reasonable limits by arithmetic law, by simula- ting the heat transfer evolution on target surface based on the one-dimensional two-temperature model, the influence of electron thermal conductivity on maximum electron temperature, on electron-phonon coupling time and electron-phonon coupling temperature was mainly discussed in the femtosecond laser ablation. The results showed that electronic thermal conductivity had different effects on electronic maximum temperature, electron-phonon coupling time and electron-phonon coupling temperature. As the electronic thermal conductivity was a reflection of the energy release rate in electronic sub-system when the surface electrons reached to the highest temperature, this led to the electronic thermal conductivity had the most significant influence on the electro-lattice coupling temperature.