Raman spectroscopic studies of explosive materials: Towards a fieldable explosives detector

Raman spectroscopy, with red (632.8 nm) and near-infrared (785 and 1064 nm) excitation, has been used to obtain high quality spectra of neat explosives. Samples with dimensions from a minimum size of 10 mu m have been analyzed utilizing a Raman microprobe fitted with a charge-coupled device (CCD) array detector. Little sample fluorescence is observed for 23 of the 32 high explosives using 632.8 nm excitation and all of the samples can be measured with a 1064 nm Nd:YAG laser. 785 nm radiation affords an excellent compromise between sensitivity and fluorescence suppression. Problems of instrumentation and sample handling have been investigated. Spectra have been obtained for explosives, both neat and in plastic and glass containers. The feasibility of sampling explosives through colored glass, which is highly fluorescent in the visible, is also demonstrated.