Laser-induced plasma on the boundary of two matrices

Abstract

In recent years, Laser-Induced Breakdown Spectroscopy (LIBS) has gained attention as a powerful technique for the elemental imaging of samples. With increasing spatial resolution and sensitivity, new challenges arise when analyzing heterogeneous samples with multiple matrices. Specifically, there is a risk of ablation at the boundary of matrices, leading to the misinterpretation of elemental maps. In this study, we investigated the behavior of plasma plumes generated on the boundary of two well-defined matrices using a combination of three-dimensional plasma imaging, spectroscopy, and Mach–Zehnder interferometry. We examined how variations in the collection optic angles with respect to the straight line defining the boundary affect the elemental distribution in plasma plumes. Consequently, the corresponding changes in signal intensities were analyzed. We also investigated the effects of slight misalignment of the optics on the measured signals. Additionally, we used Mach–Zehnder interferometry to determine the changes in electron density and to identify any changes in the plasma plume size and shape during boundary ablation. Overall, our findings provide valuable insights into the behavior of plasma plumes at the boundary of matrices and factors that need to be considered when mapping fine heterogeneous structures using LIBS.