| Laser-based sensor development has become a field of interest due to environmental and security reasons. In this work, a 266 nm fs-pulsed laser was coupled to an AFM/NSOM system to study the photochemistry of 2,4,6-Trinitrotoluene (TNT). Vibrational spectroscopy analysis performed on the dry deposits of irradiated TNT solutions reveal that the photolysis products of TNT solutions depend on the solvent nature. TNT nanosized particles were deposited on a transmissive substrate and characterized by atomic force and electron microscopy. Particle chemical composition was confirmed by surface reflectance FTIR and energy dispersive X-ray spectroscopy analysis. TNT particles showed fluorescence signal upon radiation with 266 nm pulses within the near field. The fluorescence signal is attributed to photo-dissociated NO due to TNT fragmentation, and the fluorescence yield resulted to be characteristic of a multi-photon absorption process. These results represent a significant advance in the chemical trace detection of warfare agents in open environments. |
