Time-resolved techniques as probes for the laser ablation process

Time-resolved ns-surface interferometry of a specially designed triazene polymer reveals that the surface morphology changes and thereby the surface removal occurs only during the laser pulse. Ns-shadowgraphy is used to observe the shockwave and the plume of fragments, which are generated during laser ablation. A comparison of the ablation properties of an energetic polymer at two different wavelengths (1064 and 193 nm) shows that the ejection of non-gaseous fragments (solid or liquid) is only detected after irradiation with 1064 nm. At higher laser fluences, plasma is formed, and the atomic (H), and diatomic species (CN, CH and C2) are identified.