The self-absorption effect seriously affects the accuracy of determination in laser-induced breakdown spectroscopy (LIBS). In this work, we proposed to reduce multielemental self-absorption within a wide spectral range (200-900 nm) by using microwave-assisted excitation in LIBS (MAE-LIBS). Self-absorption reduction of sodium (Na), potassium (K), aluminum (Al), silicon (Si), and calcium (Ca) in potassium feldspar using MAE-LIBS was investigated. The mechanisms of self-absorption reduction in MAE-LIBS were also investigated. The results show that the serious self-absorption of spectral lines (Na and K) was reduced. The full widths at half maximum (FWHMs) of Na I 589.0 nm, Na I 589.6 nm, K I 766.5 nm, and K I 769.9 nm in potassium feldspar were reduced by 43%, 43%, 53%, and 47%, respectively. MAE-LIBS also has a little FWHM reduction for spectral lines with weak self-absorption. The results demonstrate that MAE-LIBS can simultaneously reduce multielemental self-absorption.

The self-absorption effect is one of the main bottlenecks for the laser-induced breakdown spectroscopy (LIBS) technique. In this Letter, LIBS assisted by laser-stimulated absorption (LSA-LIBS) is proposed to solve this problem. The process of LSA in self-absorption reduction is discussed and confirmed. The serious self-absorption phenomena of spectral lines (K, Mn, and Al) were not observed in LSA-LIBS. The full width at half-maximum (FWHM) of K, Mn, and Al was reduced by about 58%, 25%, and 52%, respectively. The results demonstrate the capability of this approach to self-absorption reduction in the LIBS technique.