Ion concentrations in plasmas produced from 193 nm excimer laser irradiation of LiNbO3 in vacuum and gas atmospheres

6 pags. ; 7 figs.We have calculated the concentration of ions in the plasma produced upon ablation of LiNbO₃ with a low fluence ArF excimer laser in vacuum and different gas environments (Ar and O₂). The model shows that Li and Nb ions (with the amount of Li ions being greater than that of Nb ions) are the most abundant in the plasma with their concentrations being always above their corresponding neutral densities. In addition, we show that the concentration of excited Nb ions is relatively important while no excited Li ions are predicted. We found that the concentration of both Li and Nb ions in O₂ is slightly higher than in Ar and vacuum. Moreover, the calculated spatial evolution of the ionic species suggests that a significant fraction of the predicted ion concentration is not produced by electron–atom ionization events within the plasma; on the contrary, they might have been produced in the LiNbO₃ crystal through a nonthermal mechanism and then ejected from the target after the laser pulse.This work was partially funded by CICYT (Spain), under Project No. TIC2002-03235. F.J.G.V. acknowledges a Ramón y Cajal contract from the Spanish Ministry of Science\udand Technology (MCYT).Peer reviewe