On the enhancement of laser induced breakdown spectroscopy signal in double pulse configuration
Authors: Cristoforetti G., Legnaioli S., Palleschi V., Pardini L., Salvetti A., Tognoni E.
Autors Affiliation: Applied Laser Spectroscopy Laboratory, Istituto per i Processi Chimico Fisici, CNR, Via G.Moruzzi, 1, 56124 Pisa, Italy
Abstract: Laser Induced Breakdown Spectroscopy (LIBS) performed in double pulse (DP) configuration is a promising development of the traditional well-known LIBS, which makes use of a single laser pulse for the ablation of the sample. In the DP configuration a pair of pulses, delayed the one with respect to the other by a temporal gap of the order of 1-10 mu s, is used for the ablation of material from the target surface and consequent formation of a plasma plume; depending on the experimental conditions, large enhancements of the resulting LIBS signal can be obtained.
In this paper, the main physical mechanisms underlying double-pulse LIBS measurements are discussed, in order to obtain a deeper insight of the effects resulting in the signal enhancement obtained in DP-LIBS with respect to single pulse LIBS. The effect of laser energy, buffer gas type and density is discussed.
A model of DP LIBS is proposed in terms of the Sedov strong explosion theory.
More Information: KeyWords: LIBS; Laser; Spectroscopy; Plasma; Signal enhancement