Feature-enhanced dual-input transformer for LIBS quantitative analysis of minor-content elements

Laser-induced breakdown spectroscopy (LIBS) enables rapid, in situ quantitative compositional analysis, yet accurate quantification of minor-content elements remains difficult due to weak spectral signatures, noise, matrix effects, and line interference. Physics-informed handcrafted features are often incomplete, while purely data-driven models may learn redundant bands and spurious correlations that suppress trace signals. Two-stage pipelines further depend heavily on preprocessing and can propagate errors. Therefore, selective feature enhancement and representation learning are needed for robust minor-element quantification in LIBS.

A novel feature-enhanced dual-input transformer for LIBS quantitative analysis of minor-content elements is proposed. First, a cross-attention mechanism is employed to align tabulated single-atom emission spectra with complex-object LIBS spectra, so that physical prior knowledge can rapidly guide feature band. Second, Self-attention is applied to real, interference-contaminated LIBS spectra to learn the relative contributions of spectrally distant wavelength regions, thereby improving discrimination between informative signals and noise or spectral interference. Moreover, a gated attention-based fusion strategy is devised to balance data-driven and physics-guided, to emphasize feature bands associated with the target elements while suppressing those strongly affected by line overlap or matrix effects. The performances of the feature-enhanced dual-input transformer model proposed for quantitative analysis of minor-content elements are verified in two LIBS datasets, and key indicators such as R², RMSE, and MAE are significantly improved compared with other methods.

The proposed feature-enhanced dual-input transformer effectively integrates physics-guided with data-driven modeling to enhance the features of minor-content elements, thereby improving the accuracy of target element quantification. It offers a novel strategy to improve the performance of LIBS-based quantitative analysis of minor-content elements, thereby enabling more reliable measurements of complex materials across various application domains.