Spectroscopic Applications of Laser-Induced Plasmas

Recent spectroscopic applications of laser-induced plasmas are reviewed. Virtually all substances are susceptible to breakdown when illuminated by a sufficiently intense laser beam. In a plasma, matter breaks apart into atoms, ions, and electrons, producing a visible flash and an audible popping sound due to the acoustical shock wave generated by the sudden, high-velocity expansion of matter outward from the plasma volume. Useful information about the elemental composition of the target material can be obtained from analysis of the emissions emanating from the plasma volume. Among the applications currently being tested in many laboratories are studies of particulate as well as gaseous pollutants in air, toxic substances present in flowing wastewater, elemental content of alloys, composition of iron ores and coal samples, contaminants on the surface of microcircuit boards, and the contents of fluid inclusions in geological samples. The beauty of laser-induced plasma spectroscopy is sample accessibility.