Optical characterization of plasmas produced by concurrent application of laser and high voltage pulses

Abstract

Laser Induced Breakdown Spectroscopy (LIBS) is a simple, powerful analytic technique that is limited by a relatively low sensibility to detect traces. To improve LIBS sensitivity an option often used consists in applying a second source of excitation such as an electric discharge. This work’s goal is to investigate the interaction of a laser-produced plasma on an aluminum target with a self-triggered electric discharge. The plasma dynamics has been investigated using shadowgraphy, fast photography and the application of narrow band-pass filters to follow the evolution of the ionic and neutral species. Results show that within the initial microseconds, the spatial extent of the laser-produced plasma increases due to the presence of a low density region induced by the spark channel. Furthermore, it was found that the electric arc mainly re-excite the ionic species while the neutral ones remains unaffected.