A unique scheme has been applied for sensitive remote detection of 2,4,6-trinitrotoluene (TNT) vapor trace amounts at atmospheric pressure and 24 °C. The detection concept is based on a single laser beam inducing a tandem process: photodissociation of TNT vapor followed by highly selective detection of its photofragments vibrationally excited NO, utilizing laser-induced fluorescence with the <i>A</i><sup>2</sup>Σ<sup>+</sup>(<i>v</i>′ = 0) ← <i>X</i><sup>2</sup>Π(<i>v</i>″ = 2) transition. A detection sensitivity of at least 8 parts in 10<sup>9</sup> of TNT vapor with a signal-to-noise ratio of approximately 10 has been experimentally verified for an unfocused ~5-mJ laser beam, measured at a distance of ~15 cm from the TNT sample.
© 2001 Optical Society of America
Talya Arusi-Parpar, Dov Heflinger, and Raphael Lavi, "Photodissociation Followed by Laser-Induced Fluorescence at Atmospheric Pressure and 24 °C: A Unique Scheme for Remote Detection of Explosives," Appl. Opt. 40, 6677-6681 (2001)