Translation-free LIBS imaging based on a dual-axis laser scanning galvanometer system

Abstract

Conventional laser-induced breakdown spectroscopy (LIBS) imaging systems typically rely on motorized translation stages to move samples. However, stage-dependent architectures have limitations in non-destructive, large-area imaging, especially when analyzing immobilized specimens under in situ conditions. In this work, we replaced the traditional sample translation method with a beam deflection approach, utilizing a dual-axis laser scanning galvanometer system to adjust the deflection direction of the light beam. A telecentric F-theta field lens was introduced to correct field curvature and geometric distortions, enabling efficient scanning of stationary samples without mechanical translation. We applied the system to measure a pure copper target and a copper–silver composite target, with a scanning area of 32 mm$\times$32 mm, to evaluate its imaging performance. The plasma images reveal a noticeable center-symmetric pattern influenced by scanning angles. Moreover, spectral peak intensities at different wavelengths show markedly distinct distributions, demonstrating the wavelength-dependent interaction mechanisms. This phenomenon was explained using interference theory, thereby enabling correction of the spatial distribution of spectral intensity. This methodology provides a practical design framework for stationary-sample scanning systems, demonstrating measurable application potential in in situ analytics.