Fate of laser-induced plasma material: Particle formation and re-deposition effects in micro-LIBS scanning applications

This paper aims to investigate the fate of ablated material during LIBS imaging and assess the potential impact of re-deposited material on the sample's elemental quantification. A standard brass alloy (80/20 % Cu/Zn) embedded in pure epoxy resin was used as the sample for this study. The particles produced during the LIBS imaging experiment were collected over a large area, spanning several millimeters, and analyzed using High-Resolution Optical Microscopy and Scanning Electron Microscopy. Time-resolved Laser-Induced Plasma images were utilized to interpret the particles distribution, revealing two distinct groups —nanoparticles and microparticles—after plasma extinction. Based on these observations, the effects of plasma condensation, plasma charging, and shockwave transport on the ablated material are discussed. Finally, the impact of re-deposited particles on elemental analysis during LIBS imaging is critically examined.