Laser induced breakdown spectroscopy (LIBS) is a promising technique, analyzing spectrum of plasma, to detect elements of solid, liquid or gaseous samples. It has many advantages, including in-situ and online detection, remote analysis, non-preparation of samples, and simultaneously multi-elements detection. Aiming at detecting detrimental elements in the polluted river and water, in this paper, collinear dual-pulse (DP) Laser-induced breakdown spectroscopy (LIBS) with liquid jet was employed to analyze emission spectrum of Cu element in the CuSO4 solution. We investigated the effect of laser pulse energies ratio and time delay between two lasers on signal intensity, which were simply given by theoretical model in laser-induced plasma for explaining various behaviors of emission spectrum. It was inferred that the maximum signal enhancement of DP-LIBS experiment was roughly 4.5 times greater than that of SP case. The limit of detection (LOD) of Cu using DP-LIBS was approximately 15 times lower than that of SP-LIBS. Results of this research indicate that collinear DP-LIBS is an effective approach to improve the plasma emission intensity and reduce the value of LOD, the application of which can be considered into the environmental problem of the water pollution.
In this paper, the laser damage thresholds of the quartz glass with/without HF acid etching are investigated induced by the wavelength of the 355nm and 1064nm respectively. Laser-induced damage threshold of the quartz glass can be improved by optimizing the HF concentration and etched time. The experimental results shown that laser induced damage thresholds of quartz glass for 355nm and 1064nm were 7.1×108 W/cm<sup>2</sup> and 1.15×109 W/cm<sup>2</sup> respectively, after HF acid treatment with the 10% HF concentration and etched time 15 minutes, laser induced damage thresholds of quartz glass for 355nm changed to 1.29×10<sup>9</sup> W/cm2 and improved 81.7%, while for 1064nm changed to 1.73×10<sup>9</sup> W/cm<sup>2</sup> and improved 50.4%. The surface damage morphologies of quartz glass induced by the 355nm and 1064nm with/without HF acid etching were comparative analyzed. Finally, the laser induced damaged mechanisms of quartz glass for 355nm and 1064nm were given.