Model description of surface charging during ultra-fast pulsed laser ablation of materials

We present a model describing the dynamical mechanisms responsible for generating fast ion ejection under ultra-short pulsed laser irradiation. The model is based on a simplified drift-diffusion approach describing the evolution of the laser-generated charge carriers, their transport, and the electric field generated as a result of quasi-neutrality breaking in the irradiated target. The importance of different processes in generating the non-thermal material-ejection mechanisms is discussed. A common frame is applied to dielectrics, semiconductors, and metals and different dynamical behaviour is observed. The modelling results are in good agreement with fs pump-probe studies and measurements of the velocity distributions of the emitted ions.