脉宽对飞秒激光辐照产生温度场的数值模拟  

Numerical simulation of influence of pulse width on temperature field generated by femtosecond laser

作　　者：卢立中[1] 石云飞[1] 徐晨光[1] 徐桂东[1] 王纪俊[1] 许伯强[1] 

机构地区：[1]江苏大学理学院,江苏镇江212013

出　　处：《江苏大学学报（自然科学版）》2011年第2期199-204,共6页Journal of Jiangsu University：Natural Science Edition

基　　金：江苏省高校自然科学基础研究面上项目(07KJB140019;08KJB140003)

摘　　要：为了研究脉冲宽度对飞秒激光辐照金属后产生的电子和晶格温度场以及平衡时间的影响,基于双温耦合理论,采用有限元方法,考虑激光的空间和时间分布,数值模拟高斯分布的飞秒激光辐照金属表面产生的温度场.给出了双温方程及数值模型,得到金属材料中电子和晶格的温度场.结果表明飞秒激光的脉冲宽度不仅影响某一点处电子和晶格温度的上升速度和最大值,而且影响着温度场的空间分布;当脉冲宽度远小于皮秒量级时,电子和晶格的温度达到平衡所需时间主要取决于电子与晶格的耦合作用;而当脉冲宽度接近皮秒量级时,平衡时间主要取决于激光的脉冲宽度.该结论为飞秒激光辐照金属激励产生应力场、超声波声场等的进一步研究提供了理论基础.In order to study the influence of laser pulse width on the electron and lattice temperature fields and their equilibrium time,based on the two-temperature coupling theory,and by taking account of the spatial and temporal shape of the laser pulse,the numerical simulation of the temperature field of the metal surface irradiated by femtosecond pulse laser of Gaussian distribution was performed by using FEM.The two-temperature equations were given and the numerical model was established.The temperature fields of electron and lattice in metal materials were obtained.The results show that pulse width of femtosecond laser affects not only electron and lattice temperature rising speed and temperature maximum in one point but also spatial distribution of temperature field.The electron-lattice coupling plays a major role in the equilib-rium time when the pulse width is much lower than picosecond regime,while the laser pulse width plays a major role in the equilibrium time when the pulse width is close to picosecond regime.This study establishes a theoretical basis for stress and ultrasound fields in metal generated by femtosecond laser.

关 键 词：温度场 飞秒脉冲激光 双温模型 有限元方法 平衡时间 

分 类 号：TN241[电子电信—物理电子学]