Signal Detection of Carbon in Iron-Based Alloy by Double-Pulse Laser-Induced Breakdown Spectroscopy**supported by National Natural Science Foundation of China (No. 51374040) and the National Key Scientific Instrument and Equipment Development Project of China (No. 2014YQ120351)

Abstract

Although single-pulse lasers are often used in traditional laser-induced breakdown spectroscopy (LIBS) measurements, their measurement outcomes are generally undesirable because of the low sensitivity of carbon in iron-based alloys. In this article, a double-pulse laser was applied to improve the signal intensity of carbon. Both the inter-pulse delay and the combination of laser wavelengths in double-pulse laser-induced breakdown spectroscopy (DP-LIBS) were optimized in our experiment. At the optimized inter-pulse delay, the combination of a first laser of 532 nm and a second laser of 1,064 nm achieved the highest signal enhancement. The properties of the target also played a role in determining the mass ablation enhancement in DP-LIBS configuration.