Sensing of halocarbons using femtosecond laser-induced fluorescence.
A femtosecond laser-induced clean fluorescence technique was explored as a means to monitor halogenated alkanes in the atmosphere. Characteristic difluorocarbene radical (CF2) fluorescence in the UV-vis can be generated inside a femtosecond laser-induced filament for different halocarbons. We show that, due to different dissociation and excitation kinetics leading to fluorescence emission, it is possible to temporally resolve the characteristic fluorescence of CF2-containing halocarbons from that of background species, therefore enhancing the signal-to-noise ratio. Laboratory-scale experiments demonstrate the potential use of femtosecond laser-induced clean fluorescence for the remote sensing of halocarbons in the atmosphere. The combination of this detection strategy with LIDAR could allow the long-range monitoring of several atmospheric species with a single laser source, eventually leading to a better understanding of chemical and dynamic processes affecting global warming, ozone loss, tropospheric pollution, and weather prediction.
Gravel
J-F
JF
Department of Physics, Physical Engineering and Optics and Centre d'Optique, Photonique et Laser (COPL), Université Laval, Québec (QC), Canada G1K 7P4.
Luo
Q
Q
Boudreau
D
D
Tang
X P
XP
Chin
S L
SL
D002138:Calibration; D006845:Hydrocarbons, Fluorinated / Q000032:analysis; D006846:Hydrocarbons, Halogenated / Q000032:analysis*; D007700:Kinetics; D007834:Lasers; D013050:Spectrometry, Fluorescence / Q000379:methods
D006845:Hydrocarbons, Fluorinated; D006846:Hydrocarbons, Halogenated; C121084:difluorocarbene