Characterization of ground-state neutral and ion transport during laser ablation of Y₁Ba₂Cu₃O_7-x using transient optical absorption spectroscopy

Transient optical absorption spectroscopy has been utilized for the first time to study the transport of ground-state Y, Ba, Cu, and Ba⁺ following excimer laser ablation of Y₁Ba₂Cu ₃O_7-x pellets. Spectral broadening of the atomic lines monitored in both absorption and emission is reported, indicating the existence of gas phase collisions in the plume of ejected material. Time-of-flight velocity distributions of the nonemitting neutrals and ions determined by the absorption technique are broadened and shifted to lower velocities than the velocity distributions inferred from excited-state fluorescence in the plume. Absorption by ground-state Y⁺, YO, BaO, and CuO also has been observed with this technique. The absorption technique, and its application as an in situ monitor of neutral and ion transport during deposition of superconducting thin films, is described.