A Laser-based Sensor for Ambient Detection of Rdx and Tnt

We detect trace residues of RDX and TNT by surface photofragmentation fragment detection in real time at ambient conditions. An infrared or visible laser generates signature, NO molecular fragments, and a second, low energy, ultraviolet laser facilitates their detection by resonance enhanced multiphoton ionization. We present the effects of pump laser wavelength, laser energy, delay timing between the pump and probe beams, and analyte concentration on signal intensity. Sensitivity analyses yield RDX and TNT detection limits in the low ng/cm.