Repeated terrorist threats and the thwarted Christmas Eve bombing attempt aboard a Northwest airline heightened interest in developing THz remote sensing capabilities, especially from Homeland Security and the Defense Department, which have funded much of the Rensselaer research.
Because THz radiation transmits through almost anything that is not metal or liquid, the waves can "see" through most materials that might be used to conceal explosives or other dangerous materials, such as packaging, corrugated cardboard, clothing, shoes, backpacks and book bags.
Unlike x-rays, THz radiation poses little or no health threat. However, the technique cannot detect materials that might be concealed in body cavities.
"Our technology would not work for owners of an African diamond mine who are interested in the system to stop workers from smuggling out diamonds by swallowing them," Dr. Zhang says.
Though most of the research has been conducted in a laboratory setting, the technology is portable and eventually could be used to check out backpacks or luggage abandoned in an airport for explosives, other dangerous materials or for illegal drugs. On battlefields, it could detect where explosives are hidden.
The fact that each substance has its own unique THz "fingerprint" will show exactly what compound or compounds are being hidden, a capability that is expected to have multiple important and unexpected uses. In the event of a chemical spill, for instance, remote sensing could identify the composition of the toxic mix. Since sensing is remote, no individuals will be needlessly endangered.
"I think I can predict that, within a few years, the THz science and technology will become more available and ready for industrial and defense-related use," predicts Dr. Zhang.
|Contact: Marshall Hoffman|
Rensselaer Polytechnic Institute