Laser-induced breakdown spectroscopy: investigation of Pb resonant excitation and decay paths

摘要

A promising way of improving the sensitivity of the LIBS (Laser-Induced Breakdown Spectroscopy) technique consists in using basically two successive laser pulses instead of only one as in conventional LIBS: the first pulse generates the plasma and the second pulse selectively excites a specific quantum level of a given trace atomic species inside the plasma. The effect of this second laser pulse is to increase the emission of the atomic species of interest and therefore enhance the signal-to-noise ratio, leading to an improved detection. As a first step toward the detection of Pb in various materials, we present in this work a study of the resonant excitation and decay paths of Pb atoms in a laser-produced plasma. The ablation was performed using a Nd:YAG laser and the 2nd pulse provided by an Optical Parametric Oscillator (OPO) laser was launched several μs afterwards.