Pre-ablation laser parameter effects on the spectral enhancement of 1064 nm/1064 nm dual-pulse laser induced breakdown spectroscopy

In this paper, the effects of 1064 nm pre-ablation laser parameters on the spectral enhancement of 1064 nm/1064 nm orthogonal dual-pulse laser induced breakdown spectroscopy (DP-LIBS) were systematically analyzed with the spectral intensity of Cr I 520.84 nm and Fe I 522.72 nm for the alloy steel. The experimental results showed that DP-LIBS had a maximum spectral enhancement at the experimental conditions of the pre-ablation pulse energy 100 mJ, the main ablative pulse energy 100 mJ, the pre-ablation pulse focus above the sample surface 1 mm and overshoot the main ablative pulse light path 1 mm, respectively. The spectral enhancement factor of Cr I 520.84 nm varying with inter-pulse delay time showed two peaks, the first was 42.8 at 6 μs and the second 48.7 at 15 μs, respectively, then decreased rapidly with inter-pulse delay time increasing. Finally, the spectral enhancement mechanisms of orthogonal pre-ablation DP-LIBS were analyzed.