Detection of Homemade Explosives Using Raman Excitation at 1064 nm

Raman spectroscopy is a powerful tool for obtaining molecular structure information of a sample. While Raman spectroscopy is a common laboratory based analytical tool, miniaturization of opto-electronic components has allowed handheld Raman analyzers to become commercially available. These handheld systems are utilized by Military and Bomb squad operators tasked with rapidly identifying explosives in the field, sometimes in clandestine laboratories. However, one limitation of many handheld Raman detection systems is strong interference caused by fluorescence of the sample or underlying surface which obscures the characteristic Raman signature of the target analyte. Homemade explosives (HMEs) are produced in clandestine laboratories, and the products under these conditions are typically contaminated with degradation products, contaminants, and unreacted precursors. These contaminations often will have strong fluorescence. In this work, Raman spectra of both commercial explosives and HMEs were collected using a handheld Raman spectrometer with a 1064 nm excitation laser. While Raman scattering generated by a 1064 nm laser is inherently less efficient than excitation at shorter wavelengths, high quality spectra were easily obtained due to significantly reduced fluorescence of HMEs.