The increasing worldwide threat of terrorism requires the capability of sytems to remotely detect and identify explosives. A stand-off Raman system was built and optimised which meets these demands including the identification of substances concealed in opaque containers. To meet the challenging situations in real life, explosives and their precursors were analysed in the presence of interfering substances and on a variety of background materials, including plastics or different car doors. The influence of the laser excitation wavelength was also investigated. The stand-off distance was...