Optimally enhanced optical emission in laser-induced breakdown spectroscopy by combining spatial confinement and dual-pulse irradiation

Opt Express. 2012 Jan 16;20(2):1436-43. doi: 10.1364/OE.20.001436.

Abstract

In laser-induced breakdown spectroscopy (LIBS), a pair of aluminum-plate walls were used to spatially confine the plasmas produced in air by a first laser pulse (KrF excimer laser) from chromium (Cr) targets with a second laser pulse (Nd:YAG laser at 532 nm, 360 mJ/pulse) introduced parallel to the sample surface to re-excite the plasmas. Optical emission enhancement was achieved by combing the spatial confinement and dual-pulse LIBS (DP-LIBS), and then optimized by adjusting the distance between the two walls and the interpulse delay time between both laser pulses. A significant enhancement factor of 168.6 for the emission intensity of the Cr lines was obtained at an excimer laser fluence of 5.6 J/cm(2) using the combined spatial confinement and DP-LIBS, as compared with an enhancement factor of 106.1 was obtained with DP-LIBS only. The enhancement mechanisms based on shock wave theory and reheating in DP-LIBS are discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aluminum / chemistry
  • Chromium / chemistry
  • Confined Spaces
  • Equipment Design
  • Fluorine / chemistry
  • Krypton / chemistry
  • Lasers, Excimer*
  • Lasers, Solid-State*
  • Spectrum Analysis / instrumentation*
  • Spectrum Analysis / methods*

Substances

  • Chromium
  • Fluorine
  • Krypton
  • Aluminum