Femtosecond and Nanosecond Dual-Laser Optical Emission Spectroscopy of Gas Mixtures
A method employing an integrated femtosecond (fs) and nanosecond (ns) dual-laser system was developed to generate plasma with desired radical species from gas mixtures via a fs laser pulse and then to excite selected radical species to higher electronic states using a wavelength-tunable ns laser pulse. An optical spectrometer was used to measure the emission spectra and identify the transition from the excited electronic state to the ground state. The proposed technique has been demonstrated for an N2-CO2 mixture with various time delays between the two fs and ns pulses. The results have indicated that the population of selected radical species at the excited electronic state can be increased using the subsequent ns laser pulse, which also enhances the intensity of emission spectra allowing better identifications of the radical species. This technique holds a promise of detection and identification of signature plasma species, particularly for trace elements and long-distance standoff detections. © 2014 Society for Applied Spectroscopy.
C. Lin et al., "Femtosecond and Nanosecond Dual-Laser Optical Emission Spectroscopy of Gas Mixtures," Applied Spectroscopy, Optical Society of America, Jan 2014.
The definitive version is available at http://dx.doi.org/10.1366/13-07237
Mechanical and Aerospace Engineering
Keywords and Phrases
Dualbeam Spectroscopy; Laser-Induced Breakdown Spectroscopy; Plasma Generation; Species Manipulation
Article - Journal
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