Ultrafast heat transfer dynamics induced by femtosecond laser pulse in fused silica

Femtosecond laser interacts with material shows nonlinear absorption and low thermal diffusion due to the ultrashort pulse width and ultra-high peak power, which makes it important in the manufacturing of high-precision micro-nano devices. In this study, an ultrafast dynamic model for transient photoionization and non-equilibrium heat transfer of femtosecond laser pulses interacting with fused silica is established. By numerical solution, the spatio-temporal evolution of carrier density and non-equilibrium electron and phonon temperature of fused silica excited under femtosecond laser single pulse is obtained; the nearly linear regulation of electron-phonon coupling time in terms of laser energy density and pulse width under non-equilibrium conditions is obtained. The variation of transient electron thermal conductivity, thermal capacity and coupling coefficient are further investigated in details. And the above simulation results are analyzed and discussed in this study.