Application of LIBS spectroscopy for remote bulk detection of explosives

Laser-induced breakdown spectroscopy (LIBS) is applied to characterize explosives and other materials such as plastics and soil. A short near-infrared laser pulse (lambda = 1064 nm, t < 1 ns, E-p = 0.4 mJ) is used to induce a plasma on the surface of the material to be investigated. When recording the time evolution of the LIBS intensities emitted by specific compounds at selected wavelengths (e.g. cyanide at 388 nm or atomic carbon at 247,9 nm) the ratio of "early" and "late" LIBS intensities is a measure to analyze different materials such as explosives, plastics or soil. Significant miniaturization of the LIBS apparatus is achieved by applying a microchiplaser as excitation source, fiber optics for light guiding and microprocessor controlled electronics for data accumulation and processing. Because of this miniaturization and the non-contact operation mode such a LIBS system can easily be integrated into a conventional mine detection needle but it also finds several applications in the field of explosive detection for anti-terror purposes.