High-resolution spectroscopy of laser ablation plumes using laser-induced fluorescence

S. S. Harilal, N. L. LaHaye, M. C. Phillips

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

We report laser-induced fluorescence spectroscopy (LIF) of laser-produced plasmas under varying nitrogen pressure levels up to atmospheric pressure. The plasmas were generated on a glass target containing minor amounts of U and Al using 1064 nm, 6 ns pulses from a Nd:YAG laser. A frequency-doubled continuous-wave Ti:Sapphire laser was used as an ultra-narrowband tunable LIF excitation source to increase the magnitude and persistence of emission from selected U and Al atomic transitions in a laser-produced plasma. 2D-fluorescence spectroscopy (2D-FS) absorption/emission images were recorded at various nitrogen pressure levels, showing both excitation and emission spectral features. At lower pressure levels (⪝100 Torr), fluorescence emission was found to be well separated in time from thermally-excited emission. However, as the ambient pressure increased, the thermally-excited emission persisted for longer times along with a reduction of LIF emission persistence and intensity. The excitation spectral features showed the inherent linewidths of various transitions in the plasma, which have significantly narrower spectral linewidths than observed in emission spectra. We evaluated two nearby transitions separated by only 18 pm to demonstrate the effectiveness of fluorescence spectra over thermally-excited spectra for high-resolution studies. The present results highlight the importance of LIF as a diagnostic tool employing continuous-wave laser re-excitation, addressing some of the limitations of traditional emission and absorption spectroscopic methods.

Original languageEnglish (US)
Pages (from-to)2312-2326
Number of pages15
JournalOptics Express
Volume25
Issue number3
DOIs
StatePublished - Feb 6 2017
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Fingerprint

Dive into the research topics of 'High-resolution spectroscopy of laser ablation plumes using laser-induced fluorescence'. Together they form a unique fingerprint.

Cite this