Space-resolved real-time emission spectroscopy and in situ reflectance
measurements during film growth are used to characterize the plasma e
xpansion dynamics and the refractive index of films produced by laser
ablation of BaTiO3, respectively. The refractive index of the films re
mains nearly constant when increasing the gas pressure up to a pressur
e threshold above which it increases sharply, similar results being ob
tained either in oxygen or correlated to the changes observed in the p
lasma expansion dynamics; the results being discussed in terms of the
dependence of the length of the plume on the gas pressure and the chan
ge of the species dynamics from an expansion regime to a diffusion one
for distances close to the plume length.