Applications of the double-pulse laser-induced breakdown spectroscopy (LIBS) in the collinear beam geometry to the elemental analysis of different materials

Double-pulse laser-induced breakdown spectroscopy studies were performed on different types of materials (synthetic glasses, rocks, steels). Two Nd : YAG lasers emitting at 532 nm were combined in the collinear beam geometry to carry out double-pulse experiments at atmospheric pressure in air. For all matrices, the influence of the delay between the two laser pulses was systematically investigated from temporal and spectral analyses. Furthermore, the correlation between the excitation energy levels of the emission lines and the increases in intensity induced by the double-pulse scheme was described for each material. A comparison of the studies displayed different behaviors of the materials in the double-pulse experiments. An interpretation of the results is provided on the basis of the determination of the plasma temperatures in the single- and double-pulse configuration with the Saha–Boltzmann plot method. It also gave an insight into the potentialities and the limitations of the double-pulse laser-induced breakdown spectroscopy (LIBS) for analytical purpose so that the materials can be classified in terms of effectiveness of the double-pulse approach.