Title: Laser-induced fluorescence of filament-produced plasmas

Abstract

Self-guided ultrafast laser filaments are a promising method for laser beam delivery and plasma generation for standoff and remote detection of elements and isotopes via filament-induced breakdown spectroscopy (FIBS). Yet, there are several challenges associated with the practical application of FIBS, including delivery of sufficient laser energy at the target for generating plasma with a copious amount of emission signals for obtaining a high signal-to-noise ratio. Here, in this study, we use laser-induced fluorescence (LIF) to boost the emission signal and reduce self-reversal in the spectral profiles. Ultrafast laser filaments were used to produce plasmas from an Al 6061 alloy target at various standoff distances from 1 to 10 m. For LIF emission enhancement, a narrow linewidth continuous-wave laser was used in resonance with a 394.40 nm Al I resonant transition, and the emission signal was monitored from the directly coupled transition at 396.15 nm. Emission signal features of Al I are significantly enhanced by resonant excitation. In addition, LIF of filament ablation plumes reduces the self-reversal features seen in the thermally excited spectral profiles. Time-resolved two-dimensional fluorescence spectroscopy was performed for evaluating the optical saturation effects, which are found to be non-negligible due to high Al atomic densities inmore » the filament-produced plasmas.« less

Authors:

Kautz, Elizabeth J.  ^[1];

• Search DOE PAGES for author "Kautz, Elizabeth J."
• Search DOE PAGES for ORCID "0000-0002-6338-9223"

Phillips, Mark C.  ^[2];

• Search DOE PAGES for author "Phillips, Mark C."
• Search DOE PAGES for ORCID "0000-0001-6566-7808"

Harilal, Sivanandan S.  ^[1]

• Search DOE PAGES for author "Harilal, Sivanandan S."
• Search DOE PAGES for ORCID "0000-0003-2266-7976"

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+ Show Author Affiliations

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Univ. of Arizona, Tucson, AZ (United States)

Publication Date:

Tue Nov 23 00:00:00 EST 2021

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation

OSTI Identifier:

1906969

Alternate Identifier(s):

OSTI ID: 1832250

Report Number(s):

PNNL-SA-164939
Journal ID: ISSN 0021-8979; TRN: US2311857

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Applied Physics

Additional Journal Information:

Journal Volume: 130; Journal Issue: 20; Journal ID: ISSN 0021-8979

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

47 OTHER INSTRUMENTATION; optical sensing; plasma diagnostics; ultrafast laser filament ablation; optical properties; emission spectroscopy; ultrafast lasers; atomic spectral lines; laser induced fluorescence; plasma sources; plasma properties and parameters; fluorescence spectroscopy; femtosecond lasers