Femtosecond laser interactions with dielectric materials: insights from a detailed modeling of electronic excitation and relaxation processes

Tatiana Itina (1) , N. Shcheblanov (1)

1 LHC - Laboratoire Hubert Curien

Electronic excitation-relaxation processes induced by ultra-short laser pulses are studied numerically for dielectric targets. A detailed kinetic approach is used in the calculations accounting for the absence of equilibrium in the electronic sub-system. Such processes as electron-photon-phonon, electron-phonon and electron-electron scatterings are considered in the model. In addition, both laser field ionization ranging from multi-photon to tunneling one, and electron impact (avalanche) ionization processes are included in the model. The calculation results provide electron energy distribution. Based on the time-evolution of the energy distribution function, we estimate the electron thermalization time as a function of laser parameters. The effect of the density of conduction band electrons on this time is examined. By using the average electron energy, a new criterion is proposed based to determine damage threshold in agreement with recent experiments

Mots clés: laser damage; modeling; Boltzmann equation

Domaines: Génie des procédés

Tatiana Itina, N. Shcheblanov. Femtosecond laser interactions with dielectric materials: insights from a detailed modeling of electronic excitation and relaxation processes. 11th International Conference on Laser Ablation, COLA2011, Nov 2011, Playa del Carmen, Mexico. pp.111. ⟨ujm-00710813⟩