Portable confocal-controlled LIBS microscopy for topographic and LIBS mapping

Abstract

The on-site detection of the geometrical topography and composition distribution of unknown minerals is a key bottleneck in the field of deep space exploration and geological material analysis. A novel portable confocal-controlled laser-induced breakdown spectroscopy (PCCLIBS) scanning three-dimensional (3D) imaging method with high spatial resolution and highly integrated structure was proposed to solve this problem. The method utilizes a confocal-controlled LIBS technique to achieve precise focusing of the sample, significantly improving the spatial resolution of the LIBS mapping system. In addition, we employ a dual two-dimensional (2D) MEMS mirror scanning technique to achieve a miniaturized design of LIBS mapping system. These two technologies are combined to achieve miniaturization, high spatial resolution, and 3D LIBS microelement imaging. The method had an axial focusing ability of ∼ 60 nm and a lateral resolution of geometrical and elemental maps of around 700 nm and 10 μm, respectively, using an objective lens with a numerical aperture (NA) of 0.4. Finally, we performed the LIBS and topographic imaging of carbonaceous chondrite (Northwest Africa 13323) using the PCCLIBS system to realize multi-information of the micro-regional chemical, element, and topographic information imaging in the sample. These results demonstrate that this method is an effective approach for the elemental characterization of LIBS in samples with complex morphologies, such as in planet landing exploration and geological exploration.