Evaluation of the self-absorption reduction of minor elements in laser-induced breakdown spectroscopy assisted with laser-stimulated absorption

Reducing self-absorption is one of the most important steps in achieving accurate analyses in laser-induced breakdown spectroscopy (LIBS). In this work, LIBS assisted with laser-stimulated absorption (LSA-LIBS) was used to reduce self-absorption effects in LIBS. A wavelength-tunable laser was used to resonantly excite cold atoms and reduce their amount in laser-induced plasmas, and thus fewer cold atoms at the plasma periphery re-absorb light from the plasma center. Accordingly, the self-absorption effect was reduced. Copper (Cu) and chromium (Cr) elements in steels were taken as examples to evaluate and compare the self-absorption effects in LIBS and LSA-LIBS. The results of calculated self-absorption coefficients (SAs) supported the effectiveness in reducing self-absorption and improving analytical linearity using LSA-LIBS.