This work highlights a potential pitfall associated with using optical emission to estimate the expansion velocity of material in laser ablation plumes, specifically when the monitored emission involves transition to a state that is present in high number density. Comparisons of time-gated, spatially resolved, images of the Li(3d -> 2p) and Li(2p -> 2s) emissions arising in the nanosecond 248 nm pulsed laser ablation of LiF enabled estimation of the distribution of ground state Li atoms in the plume. Analysis of these images revealed that the density of Li(2p) atoms in the early stages of the plume expansion was sufficiently high that even the Li(3d -> 2p) emission profiles show evidence of radiation trapping.
|Title of host publication||COLA'05: 8th International Conference on Laser Ablation|
|Editors||WP Hess, PR Herman, D Bauerle, H Koinuma|
|Place of Publication||BRISTOL|
|Publisher||Deutsche Physikalische Gesellschaft & IOP Publishing Ltd|
|Number of pages||4|
|Publication status||Published - 2007|