Multifiber Dimension-Conversion Laser-Induced Breakdown Spectroscopy (MFDC-LIBS): Real-Time Spatially Resolved LIBS for Enhanced Quantification in Heterogeneous Matrices

Laser-induced breakdown spectroscopy (LIBS) has been widely applied in compositional analysis due to its advantages, such as rapid detection and simple operation. However, the uneven distribution of elements in the laser-induced plasma plume has consistently restricted the accuracy and stability of its quantitative analysis, limiting its practical application in in situ analysis. Herein, a multifiber dimension-converting LIBS (MFDC-LIBS) proof-of-concept system was developed to understand the differentiated characterization of elemental distribution within the same plasma plume. The MFDC-LIBS system employs 100 optical fibers to simultaneously collect two-dimensional spatial distribution information from different positions within the plasma plume. By developing an innovative array-to-linear transformation concept and using a reflection grating for spectral dispersion, the plasma images were directly captured by an area-array complementary metal-oxide-semiconductor (CMOS) detector. It was found that the MFDC-LIBS system significantly improves linearity and enhances the quantitative accuracy and stability of LIBS. The quantitative results show that the RMSE was reduced by 74% for Ca, 70% for Ba, 77% for Mg, and 66% for Na with rock samples. The MFDC-LIBS system offers a robust and scalable approach that merges spatial diagnostics with enhanced analytical precision for the LIBS analysis of complex solid materials.