中国物理B ›› 2004, Vol. 13 ›› Issue (10): 1758-1765.doi: 10.1088/1009-1963/13/10/033

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Thermalization time of thin metal film heated by short pulse laser

张元冲1, 宋亚勤1, 徐红玉2, 陈殿云3   

  1. (1)Department of Engineering Mechanics, Xi'an Jiaotong University, Xi'an 710049, China; (2)Department of Engineering Mechanics, Xi'an Jiaotong University, Xi'an 710049, China; School of Architecture Engineering, Henan University of Science and Technology, Luoyang 471003, China; (3)School of Architecture Engineering, Henan University of Science and Technology, Luoyang 471003, China
  • 收稿日期:2004-01-09 修回日期:2004-05-15 出版日期:2004-10-20 发布日期:2005-06-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10132010).

Thermalization time of thin metal film heated by short pulse laser

Xu Hong-Yu (徐红玉)ab, Zhang Yuan-Chong (张元冲)a, Song Ya-Qin (宋亚勤)a, Chen Dian-Yun (陈殿云)b   

  1. a Department of Engineering Mechanics, Xi'an Jiaotong University, Xi'an 710049, China; b School of Architecture Engineering, Henan University of Science and Technology, Luoyang 471003, China
  • Received:2004-01-09 Revised:2004-05-15 Online:2004-10-20 Published:2005-06-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10132010).

摘要: Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au), copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds. The thermalization time decays exponentially with the increase of phonon-electron coupling factor or electron gas thermal conductivity, and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time.

关键词: non-equilibrium thermal behaviour, thermalization time, hyperbolic two-step model, short pulse laser

Abstract: Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au), copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds. The thermalization time decays exponentially with the increase of phonon-electron coupling factor or electron gas thermal conductivity, and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time.

Key words: non-equilibrium thermal behaviour, thermalization time, hyperbolic two-step model, short pulse laser

中图分类号:  (Integral transforms)

  • 02.30.Uu
44.10.+i (Heat conduction) 71.10.Ca (Electron gas, Fermi gas) 02.30.Zz (Inverse problems) 61.80.Ba (Ultraviolet, visible, and infrared radiation effects (including laser radiation))