Photoluminescence spectroscopy for explosives detection

University of Florida researchers have discovered a way to use photoluminescence spectroscopy to detect explosives from a distance. The basic idea is to shine a laser at the object and look at the spectrum of radiation emitted by the object. TNT and other explosives (including plastic explosives and nitroglycerin) have a common and specific well-defined signature corresponding to the presence of two nitro groups.

The development provides instantaneous results, gives no false positives, can be used remotely and is portable -- attributes [Professor Hummel] says will make it indispensable at all levels of law enforcement, from local police to homeland security. “ If I see a ship approaching, I’d like to know if it’s packed with explosives,” Schau said. It’s in the field of remote detection that this is exciting. This really looks like it may give us a leg up on that.” Sample collection for explosives is familiar to anyone who has recently passed through an airport: a swab brushed across an object, such as a suitcase, clothing or even a person, or puffs of air blasted across a filter that can trap tiny amounts of airborne explosives. The advantage of photoluminescence-based explosive detection is that it can be remotely applied, and requires neither time-consuming and expensive machines nor trained dogs, said Hummel, who has applied for a patent on the technique.