Bessel beams: a potential strategy for laser-induced breakdown spectroscopy

Abstract

Laser-induced breakdown spectroscopy (LIBS) is a rapid, in situ, real-time detection technique. However, violent fluctuation of spectral signal caused by the uneven surfaces of actual samples severely reduces the accuracy and stability of LIBS. Bessel beam is a kind of “non-diffracting beam” with the advantage of extended linear focus. Due to the uniform distribution of laser fluence in the extended focus, the Bessel beam is considered an alternative for LIBS analysis on uneven samples. In this study, LIBS based on Bessel beam was proposed to analyze alloyed steel tube and slanting steel samples. The results showed that the RSDs of the steel tube intensity ablated by the Bessel beam was below 20%, half of the Gaussian beam. Also, the quantitative analysis of the slanting steel samples based on the Bessel beam had higher accuracy and stability (R² = 0.956, ARSD = 10.12%), which is better than the Gaussian beam (R² = 0.933, ARSD = 24.78%). This research provides a new method to achieve rapid and accurate LIBS detection for uneven surface samples.