The effect of sample temperature on the emission line intensification mechanisms in orthogonal double-pulse Laser Induced Breakdown Spectroscopy

Orthogonal double-pulse laser ablation on aluminum-based alloy target at atmospheric pressure was investigated by time-resolved optical emission spectroscopy. Studies were performed as a function of the distance from the first pulse plasma induced in air to the sample surface. Double-pulse experimental results were compared to single-pulse laser ablation experiments carried out in a heated target to up to 500 °C. Emission line intensification mechanisms are discussed in terms of the sample heating by the pre-ablation pulse. Crater volume was also determined via confocal microscopy for both, double pulse and target heating, experiments. It was found that the emission intensification is mainly due to an enhancement of the ablated mass. The mechanisms for the mass removal increasing are discussed.

► Emission enhancement in orthogonal double pulse (DP) LIBS were investigated.
► DP-LIBS results were compared to single pulse LIBS onto a heated target.
► Target heating produced by the air plume contributes to DP emission intensification.