Fluorescence quantum yield of carbon dioxide for quantitative UV laser-induced fluorescence in high-pressure flames

• Published in: Applied physics. B, Lasers and optics Lasers and optics, 2008-11, Vol.93 (2-3), p.677-685
• Main Authors: Lee, T., Bessler, W. G., Yoo, J., Schulz, C., Jeffries, J. B., Hanson, R. K.
• Format: Article
• Language: English
• Subjects: Biological and medical applications; Carbon dioxide; Combustion; Engineering; Exact sciences and technology; Excitation; Fluorescence; Fundamental areas of phenomenology (including applications); Image forming and processing; Imaging and optical processing; Laser spectroscopy; Lasers; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Spectra; Ultraviolet; Wavelengths
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-008-3161-9

The fluorescence quantum yield for ultraviolet laser-induced fluorescence of CO 2 is determined for selected excitation wavelengths in the range 215–250 nm. Wavelength-resolved laser-induced fluorescence (LIF) spectra of CO 2 , NO, and O 2 are measured in the burned gases of a laminar CH 4 /air flame ( φ =0.9 and 1.1) at 20 bar with additional NO seeded into the flow. The fluorescence spectra are fit to determine the relative contribution of the three species to infer an estimate of fluorescence quantum yield for CO 2 that ranges from 2–8×10 −6 depending on temperature and excitation wavelength with an estimated uncertainty of ±0.5×10 −6 . The CO 2 fluorescence signal increases linearly with gas pressure for flames with constant CO 2 mole fraction for the 10 to 60 bar range, indicating that collisional quenching is not an important contributor to the CO 2 fluorescence quantum yield. Spectral simulation calculations are used to choose two wavelengths for excitation of CO 2 , 239.34 and 242.14 nm, which minimize interference from LIF of NO and O 2 . Quantitative LIF images of CO 2 are demonstrated using these two excitation wavelengths and the measured fluorescence quantum yield.