Femtosecond filament-laser ablation molecular isotopic spectrometry

Abstract

A new remote sensing technology for real-time isotopic analysis is introduced: Femtosecond Filament-Induced Laser Ablation Molecular Isotopic Spectrometry (F 2-LAMIS). The technique combines femtosecond (fs) laser filamentation and ablationbased molecular isotopic spectroscopy, thereby enabling isotopic analysis of samples at a distance, in ambient air and at ambient pressure conditions. Isotopic analysis of zirconium (Zr) samples by F 2-LAMIS is demonstrated, and the molecular and atomic emission intensity, and properties of the filament-induced plasma generated at different filament propagation distances were investigated. Spectral fitting of F 2-LAMIS spectra enabled semi-quantitative isotopic analysis without the use of calibration standards, which was independent of the filament propagation distance for the studied range. This technology provides new capabilities for direct isotopic ratio measurements at remote distances.

The 2017 Plasma Roadmap: Low temperature plasma science and technology

“…Bursting on the plasma scene in recent years has been the reemergence of an old tool, in the guise of laser-induced breakdown spectroscopy (LIBS) and its new sister laser-assisted molecular emission spectrometry (LAMIS) [142]. LIBS involves generating a laser-induced plasma on or near the surface of a sample; the species volatilized, atomized and ionized by the plasma can then be observed by OES, often at a distance.…”

“…The advantage is that molecular bands exhibit a much larger isotope shift than atomic lines, so measured spectra can be used for isotope analysis, even at a distance. When coupled with laser filamentation [142], such arrangements promise the possibility of performing atomic or isotope analysis at extended distances, perhaps on the km scale.…”

Standoff Detection of Uranium and its Isotopes by Femtosecond Filament Laser Ablation Molecular Isotopic Spectrometry

“…The upper energy level associated with the U II 424.43 nm emission is 3.03 eV32. In previous studies by Hou et al 27. and Harilal et al 33,.…”

“…In prior profilometry measurements of the filament ablation craters in similar experimental conditions27, it has been observed that the greatest mass removal occurs at the peak of the molecular emission. The origin of the molecular emission from a non-oxidized sample has been shown to be due to the formation of diatomic molecules through reactions with the ambient atmosphere212527. The increase of the atomic, ionic, and molecular emission suggests that an increase of the mass of ablated uranium produces an increase in the density of U I, U II, and U x O y within the plasma.…”

Combination of atomic lines and molecular bands for uranium optical isotopic analysis in laser induced plasma spectrometry

“…There are three objectives in the present study. Currently, the heaviest element measured with LAMIS for isotopic analysis is Zr (Z = 40) [5,20].…”