Study of thermal physical parameters in high energy domain femtosecond laser ablation on Au film

Abstract

On the basis of the two-temperature model (TTM), the influence of electronic heat capacity(Ce), electroacoustic coupling coefficient(G) and electron thermal conductivity(Ke) is simulated, contrasted and analyzed by finite element method and method of control variables on three ablation properties in femtosecond laser ablation on 800nm Au film with a 60 ps laser pulse at 1.5 Jcm−2. Maximum electron temperature, electroacoustic coupling time and electroacoustic coupling temperature are selected to describe the three ablation properties. The results show that all the three thermal physical parameters (Ce, G and Ke) have different degrees of effects on three ablation properties simultaneously. While Ce has the biggest influence on maximum electronic temperature, the effects of G on electroacoustic coupling time is the most prominent, and Ke is the key factor for electroacoustic coupling temperature change. Finally the physical mechanism of three parameters influencing ablation results is analyzed and explained, the main reason for these conclusions is that the electron thermal capacity describes the thermal energy capacity of electronic subsystem, the electroacoustic coupling coefficient represents the energy conversion capacity between the electronic subsystem and the lattice subsystem, and the physical nature of the electronic thermal conductivity is the speed of energy transmission within the electronic subsystem.