Depth profile analysis of layered samples using glow discharge assisted Laser-induced Breakdown Spectrometry (GD-LIBS)

A microsecond-pulsed glow discharge is used to excite ablate material generated by the ablation laser in Laser-induced Breakdown Spectrometry (LIBS). The coupled system provides a simple means to excite the material ablated by the incident laser pulse by taking advantage of enhanced collisional excitation. In this way, one can effectively reduce laser energies below the excitation and ionization thresholds to those needed solely for ablation of the sample surface, in which the excitation of the material is performed by a high voltage discharge. Given this development, there exists the potential of improving upon depth resolutions in LIBS material characterization. This article presents the results of a comparative depth profile study conducted on various galvanized steels and layered brass standards by LIBS and GD-LIBS; demonstrating the advantages of coupling a pulsed glow discharge with a typical LIBS set-up used in materials analysis.