Al2O3 ceramics under high-fluence irradiation: plasma plume dynamics through space- and time-resolved optical emission spectroscopy

The dynamics of a transient laser ablation plasma plume has been investigated by means of space- and time-resolved optical emission spectroscopy (OES), through a high-resolution monochromator and a fast gate ICCD camera. The experiments have been carried out with the third harmonic (355 nm) of a Q-switched (10 ns) Nd:YAG laser focused on Al2O3 samples placed in a vacuum chamber (10−7 Torr). The splitting of the plasma plume into two components has been evidenced by ICCD imaging. In the OES study, Al and O neutral atoms and different charge state ions have been monitored through the evolution of selected spectral lines. The two plume components (fast and slow) are found to consist mainly of charged and neutral species, respectively. Fundamental parameters of these species (e.g. excitation temperature) have been derived.