Femtosecond-laser-induced plasma spectroscopy for high-pressure gas sensing: Enhanced stability of spectroscopic signal

• Published in: Applied physics letters 2018-11, Vol.113 (21)
• Main Authors: Hsu, Paul S., Patnaik, Anil K., Stolt, Adam J., Estevadeordal, Jordi, Roy, Sukesh, Gord, James. R.
• Format: Article
• Language: English
• Subjects: Applied physics; Combustion chambers; Detection; Electric power generation; Engineering research; Gas composition; Gas sensors; Laser applications; Laser induced breakdown spectroscopy; Laser plasmas; Lasers; Plasma spectra; Power plants; Spectrum analysis; Stability analysis
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.5054805

Gas composition detection and analysis in high-pressure environments, such as those encountered in combustors, power plants, and planetary bodies, are important for scientific and engineering research. Conventional laser-based sensing using nanosecond (ns)-laser-induced breakdown spectroscopy (ns-LIBS) remains unreliable at elevated pressures because of the relatively high measurement uncertainty. To circumvent this problem, we propose to employ femtosecond-laser-induced plasma spectroscopy (FLIPS) to achieve a stable and reliable gas sensing at elevated pressures. A comprehensive study on the differences in the measurement quality of FLIPS and ns-LIBS for high-pressure nitrogen gas is conducted. The results show that the signal level and stability of ns-LIBS significantly decrease with the increase in pressure. In contrast, the signal level of FLIPS increases with the increase in pressure while maintaining the stability in the pressure range of 1–40 bar. In addition to the superior measurement stability, the FLIPS measurement provides a longer probe length (∼3 times compared to ns-LIBS) with a higher data acquisition speed (100 times compared to 10-Hz ns-LIBS).