Continuum removal and self-absorption correction incalibration-free laser-induced breakdownspectroscopy for efficient elemental analysis

Abstract

Even though laser-induced breakdown spectroscopy (LIBS) has emerged as a powerful analytical technique, the broad continuum emission and self-absorption effects in laser-produced plasmas (LPP) limit the accuracy of the LIBS technique in multi-elemental compositional analysis. In this work, we developed an algorithm to detect and remove the broad continuum emission, which usually originates from free-free and free-bound transitions. To eliminate the continuum, the segment-wise background correction method (using identified continuum parts of varied range) was used. The spectral interference of lines is more likely to be found in LIBS spectra, especially with low-resolution spectrometers. A Lorentzian curve fitting method was used to resolve closely spaced emission lines. The ‘internal reference self-absorption correction (IRSAC)’ method was introduced to correct the reabsorption effects in LPPs. When these methods are applied to LIBS data of bronze alloy, more accurate quantitative findings are obtained, with a major component accuracy error of less than 10% when compared to its reference abundance.

Impact of intensity error on temperature estimation in laser-induced breakdown spectroscopy: a numerical study

“…Therefore, for accurate temperature evaluation, which is often in demand in most situations, we may adopt SBP and MESBP methods. Apart from these, we also need to consider the proper calibration of the detectors, self-absorption corrections of prominent emission lines, and laser pulse energy stabilization to reduce the uncertainty in analytical measurements with the laser-induced breakdown spectroscopy technique [41][42][43].…”

Delving into the time dependent properties of thorium laser induced plasma by optical emission spectroscopy

“…In LIP, the effective collisions between heavier species and free electrons are instrumental in establishing equilibrium majorly by collisional excitation/de-excitation or ionization/recombination pathways, while radiative pathways act as minor ones. The radiative energy emerges through the process of electron-ion recombination, representing non-quantized energy along with having the contribution of free-free transition [25,26]. This is responsible for creating the high continuum at early acquisition delay, and decays gradually with time.…”

A numerical procedure for understanding the self-absorption effects in laser induced breakdown spectroscopy

“…4 Our study shows that we should depend on the self-absorption correction methods to get a precise compositional result. 7,10,11,16,28,[42][43][44][45] In addition to self-absorption correction methodologies, there are various methods for overcoming the self-absorption effect. 7,10,11 One important method is reducing the plasma density by the ambient pressure control method, and the self-absorption coefficient can be brought close to one.…”