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Chemicals used in explosives give off signatures that can be read by spectroscopic systems. One practical application for this technology would be for use at airport screening stations. A spectroscopic detection system would be able to tell the difference between explosive chemicals and shampoo by measuring the spectroscopic signature given off by a traveler’s bag. The chemicals and the shampoo absorb radiation frequencies given off by spectroscopic systems to different degrees, so each material has a unique absorption profile that can be detected by the system.
Until now, detection using one of the broadest and most important bands of electromagnetic signatures – the terahertz region – has not been practical because its detection technology can take more than 30 minutes to work and is cumbersome.
Recently, researchers at the Massachusetts Institute of Technology, the Netherlands Institute for Space Research, and NNSA’s Sandia National Laboratories worked together to produce a tiny system that will drastically cut detection time for terahertz spectroscopy.
The device works by emitting terahertz radiation in a variety of frequencies, evenly-spaced spaced out in a “comb.” Materials absorb the very exact radiation frequencies and give off different signatures for detection. The new spectroscopy system reads a material’s spectroscopic signature in about 100 microseconds. For perspective, a microsecond is a millionth of a second; the average human eye blink takes 350,000 microseconds. The new system uses a laser about the size of a penny.