Ultrafast laser ablation of metals with a pair of collinear laser pulses

Abstract

We investigated the process of ultrafast laser ablation of metallic targets induced by a pair of identical laser pulses, with either p or s polarizations, temporally delayed from ≈1 ps to a few nanoseconds. We used fast ion probe diagnostics to characterize the ion plume at the moderate laser intensity (≈1012 W/cm2) typically employed in ultrafast laser deposition and material processing. We observed a consistent time-correlated enhancement of the ion yield and velocity, which lends itself to an interesting and useful method for manipulating ablation plasma characteristics. The mechanisms producing this feature are also discussed.