Analytical-performance enhancement of laser-induced breakdown spectroscopy using an annular laser beam

Abstract

In this paper, an axicon and a spherical lens were used to convert a circular Gaussian beam into an annular beam. Plasma was produced by a Q-switched Nd:YAG laser from an alloy steel sample with the annular beam. The spectral characteristics and analytical performance of trace elements using annular and Gaussian beam laser-induced breakdown spectroscopy (LIBS) were compared. The annular beam produced a larger stable plasma region with a flat spatial distribution. A 2–3 times enhancement in spectral stability was observed, while detection sensitivity increased by 2.1 times and the limit of detection (LoD) was reduced by 38.5%. The results of this study demonstrated that the plasma induced by an annular laser beam provides a new method to improve the analytical performance of LIBS.