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.
Department of Physics, Physical Engineering and Optics and Centre d'Optique, Photonique et Laser (COPL), Université Laval, Québec (QC), Canada G1K 7P4.
J-F
JF
Gravel
Q
Q
Luo
D
D
Boudreau
X P
XP
Tang
S L
SL
Chin
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