Is That Anthrax? Perhaps You Want to Check From a Distance

by Gabrielle DeMarco on December 28, 2009

The best way to prevent yourself from inhaling deadly anthrax spores is to keep a safe distance. But how can you tell if you are in fact dealing with anthrax if you can’t get close to that suspicious package? Or take a similar dilemma – How can you can you detect the level of a specific environmental pollutant in the atmosphere without ever leaving the ground?

Researchers Jingle Liu and X.C. Zhang of the Rensselaer Center for Terahertz Research  have developed a new terahertz (THz) technology that can remotely detect many toxic biochemicals, explosive materials, and atmospheric pollutants. Called Thz-REEF (radiation-enhanced-emission-of-fluorescence), the technology is the first of its kind to remotely perform high resolution THz spectroscopy.

THz-REEF allows remote sensing of materials up to 10 meters away (nearly 33 feet). Before this invention, THz technology needed to be very close to the object that it was analyzing due to the disruption of the THz waves as they moved through the moisture within the surrounding air. The new system uses laser-induced gas plasma to avoid disruption of the THz signal as it moves through the air.

For all those new to the THz region, it is on the electromagnetic spectrum between microwaves and visible light. Like its much shorter cousins, X-rays, T-rays (as they also often called) can penetrate a material to image it or something inside of it. But, unlike X-rays, T-rays are not destructive. This means they can be used safely and repeatedly on substrates as delicate as the human body. They can also be used to provide a THz “fingerprint” of a material. In the case of anthrax, it has a particular spectral fingerprint in the THz region that a computer can instantly read and recognize as different from a more mundane substance like baby powder.