Spectrally Resolved Imaging of Ultrashort Laser Produced Plasma

A spectrally resolved imaging technique is introduced to investigate the spatial and temporal evolution of different plasma plume components [ions, atoms and nanoparticles (NPs)] produced during ultrashort laser ablation of a pure copper target. The temporal evolution of neutral (Cu^*) and ionic (Cu+) components of the atomic plasma are separately imaged by exploiting bandpass interference filters in front of a fast-gated intensified charge coupled device camera, whereas for the NPs plume, its broadband emission is imaged. The 2-D spectrally resolved images show a dominant neutral component in the atomic plasma plume emission and a faster, well-separated ionic component moving ahead of it. The more massive, slow NPs plume follows at much longer delay.