Time-resolved optical emission during laser ablation of Cu, CuO, and high-Tc superconductors: Bi1.7Sr1.3Ca2Cu3Ox and Y1Ba1.7Cu2.7Oy

Time-resolved measurements of optical emission from the ablation plume of ArF excimer-laser-irradiated Cu, CuO, Bi_1.7Sr_1.3Ca₂Cu₃O_x, and Y₁Ba_1.7Cu_2.7O_y are reported. Data were collected on several emission lines for a variety of neutral and ionic species, including Cu⁺, Cu, Sr⁺, Sr, Ca⁺, Ca, and Y. The time dependence of the emission intensity is analyzed to obtain effective particle velocities. The results indicate most probable velocities of (3-10)×10⁵ cm/s for the neutral species and (1-2)×10⁶ cm/s for the ions, in qualitative agreement with previous work. However, the time dependence of the optical emission intensity can be influenced by radiation trapping and the detailed mechanisms of species excitation. These effects are shown to complicate the quantitative relationship between the emission intensity versus time and the particle velocity.