Improved two-temperature model and its application in femtosecond laser ablation of metal target

Abstract

An improved two-temperature model to describe femtosecond laser ablation of metal target was presented. The temperature-dependent heat capacity and thermal conductivity of the electron, as well as electron temperaturedependent absorption coefficient and absorptivity are all considered in this two-temperature model. The tailored twotemperature model is solved using a finite difference method for copper target. The time-dependence of lattice and electron temperature of the surface for different laser fluence are performed, respectively. The temperature distribution of the electron and lattice along with space and time for a certain laser fluence is also presented. Moreover, the variation of ablation rate per pulse with laser fluence is obtained. The satisfactory agreement between our numerical results and experimental data indicates that the temperature dependence of heat capacity, thermal conductivity, absorption coefficient and absorptivity in femtosecond laser ablation of metal target must not be neglected. The present model will be helpful for the further experimental investigation of application of the femtosecond laser.

Single-step synthesis of graphene quantum dots by femtosecond laser ablation of graphene oxide dispersions

“…This phenomenon can be simulated by a two temperature model in which, heat transfer equations are used to express the electronic and atomic temperatures as a function of time, position, initial temperature and heat input to the system. [57][58][59] A specific term has been added to these two couple heat transfer equations to model the energy transfer from electrons to atoms. The governing equations for this simulation are as follows:…”

Laser Coupling and Relaxation of the Absorbed Energy: Metals, Semiconductors, and Dielectrics

“…For dielectrics, the major effect stems from a large increase in the density of free carriers, while for metals the effect is due to changes in the (electron) temperature and associated altered scattering times. Most investigations indicate that quite high excitations are needed for the effect to play a significant role (Fang et al 2010;Banks et al 2000;Fisher et al 2005;Guo 2005, 2011), while other studies show a contribution already at intensities close to the threshold for ablation (Kirkwood et al 2009;Ren et al 2011).…”

Effects of laser pulse heating of copper photocathodes on high-brightness electron beam production at blowout regime

“…This process is successfully described by the well-known two temperature model. In this paper an improved twotemperature model [14,15] is employed, which considers the effects of lattice and electron temperatures on the reflectivity coefficient, the electron heat capacity, the electron thermal conductivity, and the electron-phonon coupling over a wide range.…”

“…The parameters for C e = γT e with γ = 96.6 J/cm 3 • K 2 and G = 10 17 W/m 3 K are widely used in many works [12,15]. These estimations are only valid, however, at low electron temperature (0 < T e < 3000 K) [16].…”