Critical density effects in sub-picosecond laser-ablation of silicon by plasma-absorption ion-energy spectroscopy

Summary from only given. It is shown in this work that the critical density condition of a plasma initially formed by a single pulse can be subsequently modified by the pumping action of a secondary time-delayed pulse. We show the results of measuring total ion yield and average energy in a pre-formed ablation plume generated by a 120 femtosecond (780 nm) laser pulse followed by an identical time delayed pulse.