Nanosecond laser-induced breakdown assisted by femtosecond laser pre-ionization in air: the effect on spatial resolution and continuous radiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20701
Author(s):  
Bo Li ◽  
Xiaofeng Li ◽  
Zhifeng Zhu ◽  
Qiang Gao
Keyword(s):  
Femtosecond Laser ◽  
Spatial Resolution ◽  
Laser Induced Breakdown Spectroscopy ◽  
Nanosecond Laser ◽  
Breakdown Threshold ◽  
Powerful Technique ◽  
Breakdown Spectroscopy ◽  
Continuous Radiation ◽  
Laser Induced Breakdown

Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for quantitative diagnostics of gases. The spatial resolution of LIBS, however, is limited by the volume of plasma. Here femtosecond-nanosecond dual-pulsed LIBS was demonstrated. Using this method, the breakdown threshold was reduced by 80%, and decay of continuous radiation was shortened. In addition, the volume of the plasma was shrunk by 85% and hence, the spatial resolution of LIBS was significantly improved.

Molecular signatures in femtosecond laser-induced organic plasmas: comparison with nanosecond laser ablation

2016 ◽  
Vol 18 (4) ◽  
pp. 2398-2408 ◽  
Author(s):  
Jorge Serrano ◽  
Javier Moros ◽  
J. Javier Laserna
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Laser Induced Breakdown Spectroscopy ◽  
Nanosecond Laser ◽  
Molecular Signatures ◽  
Optical Monitoring ◽  
Molecular Sensing ◽  
Breakdown Spectroscopy ◽  
Nanosecond Laser Ablation ◽  
Laser Induced Breakdown

During the last few years, laser-induced breakdown spectroscopy (LIBS) has evolved significantly in the molecular sensing area through the optical monitoring of emissions from organic plasmas.

EXPRESS: Laser-Induced Breakdown Spectroscopy (LIBS) Combined with Temporal Plasma Analysis of C2 Molecular Emission for Carbon Analysis in Coal

2021 ◽  
pp. 000370282110123
Author(s):  
Hemalaxmi Rajavelu ◽  
Nilesh J Vasa ◽  
Satyanarayanan Seshadri
Keyword(s):  
Elemental Carbon ◽  
Partial Least Square ◽  
Laser Induced Breakdown Spectroscopy ◽  
Nanosecond Laser ◽  
Calibration Model ◽  
Breakdown Spectroscopy ◽  
Persistence Time ◽  
Relative Standard ◽  
Laser Induced Breakdown ◽  
Spectral Intensities

A benchtop Laser-Induced Breakdown Spectroscopy (LIBS) is demonstrated to determine the elemental carbon content present in raw coal used for combustion in power plants. The spectral intensities of molecular CN and C2 emission are measured together with the atomic carbon (C) and other inorganic elements (Si, Fe, Mg, Al, Ca, Na, and K) in the LIBS spectrum of coal. The emission persistence time of C2 molecule emission is measured from the coal plasma generated by a nanosecond laser ablation with a wavelength of 266 nm in the Ar atmosphere. The emission persistence time of molecular C2 emission along with the spectral intensities of major ash elements (Fe, Si, Al, and Ca) and carbon emissions (atomic C, molecular CN, and C2) shows a better relationship with the carbon wt% of different coal samples. The calibration model to measure elemental carbon (wt%) is developed by combining the spectral characteristics (Spectral intensity) and the temporal characteristics (Emission persistence time of C2 molecule emission). The temporal characteristic studies combined with the spectroscopic data in the PLSR (Partial Least Square Regression) model has resulted in an improvement in the root mean square error of validation (RMSEV), and the relative standard deviation (RSD) is reduced from 10.86% to 4.12% and from 11.32% to 6.04%, respectively.

Sign in / Sign up

Export Citation Format

Share Document