Abstract

The emission of the plasma generated when a pulsed CO₂ laser is used to evaporate an optical thin-film material is analyzed by means of an optical multichannel analyzer in the 200-900-nm region. Source materials were Al₂,O₃, SiO₂, HfO₂, TiO₂, and ZnO, which are absorbing at 10.6 µm. Very rich atomic spectra were obtained indicating the presence of excited neutrals, as well as singly, doubly, and triply ionized anions and cations. Molecular emission (e.g., Al–O) was observed when background gas pressures of O₂, He, Ar, or N₂ were increased to the range of 0.1–10 Torr. The optical power dependence of the emission intensity is nonlinear, indicating saturation behavior.

© 1985 Optical Society of America