Spatiotemporal spectroscopic characterization of plasmas induced by non-orthogonal laser ablation

journal article in Web of Science

English

Ablation geometry significantly affects the plasma parameters and the consequent spectroscopic observations in laser-induced breakdown spectroscopy. Nevertheless, plasmas induced by laser ablation under inclined incidence angles are studied to a significantly lesser extent compared to plasmas induced by standard orthogonal ablation. However, inclined ablation is prominent in stand-off applications, such as the Curiosity Mars rover, where the orthogonality of the ablation laser pulse cannot be always secured. Thus, in this work, we characterize non-orthogonal ablation plasmas by applying plasma imaging, tomography, and spectral measurements. We confirm earlier observations according to which non-orthogonal ablation leads to a laser-induced plasma that consists of two distinct parts: one expanding primarily along the incident laser pulse and one expanding along the normal of the sample surface. Moreover, we confirm that the former emits mainly continuum radiation, while the latter emits mainly sample-specific characteristic radiation. We further investigate and compare the homogeneity of the plasmas and report that inclined ablation affects principally the ionic emissivity of laser-induced plasmas. Overall, our results imply that the decreased fluence resulting from inclined angle ablation and the resulting inhomogeneities of the plasmas must be considered for quantitative LIBS employing non- orthogonal ablation.

laser-induced plasma, laser-induced breakdown spectroscopy, non-orthogonal ablation, plasma tomography, Radon reconstruction

KÉPEŠ, E.; GORNUSHKIN, I.; POŘÍZKA, P.; KAISER, J.

23. 11. 2020

Royal Society of Chemistry

0003-2654

ANALYST

146

3

United Kingdom of Great Britain and Northern Ireland

920

929

10

https://pubs.rsc.org/en/content/articlepdf/2021/AN/D0AN01996H

http://hdl.handle.net/11012/196476

D0AN01996H.pdf