Spectral characteristics of laser-induced plasma under the combination of Au-nanoparticles and cavity confinement

Abstract

To enhance the emission spectrum intensity of laser-induced plasma, a method of combining cavity-enhanced laser-induced breakdown spectroscopy (LIBS) with nanoparticles-enhanced LIBS (NELIBS) was proposed. In this paper, the brass with Au-nanoparticles deposited on the surface is placed under the condition of cavity confinement and cavity-free confinement, and the differences between various performances are analyzed. The experimental results show that spectral line enhancement effect is the best when cavity confinement diameter is 5 mm. When cavity-enhanced LIBS is combined with NELIBS, the plasma intensity is effectively enhanced, and the enhancement factor is up to 20.24 (Cu I 515.4 nm); signal-to-noise ratio (SNR) is improved significantly, and it reaches 337.21 when pulse energy is 60 mJ. Electron temperature is in the range of 12,040–14,260 K and electron density is increased, the ability of detect trace elements is greatly improved. Keywords: LIBS, Au-nanoparticles, Cavity confinement, Electron temperature, SNR