John Federici, a physics professor at NJIT, sees the use of terahertz rays as a critical technology in the defense against suicide bombers and other terrorist activities. Federici and his research team recently described experimental results from a digital video camera invented in their laboratory that uses a terahertz imaging system. One day such a device could be used to scan airport passengers quickly and efficiently. "Video-Rate terahertz Interferometric and Synthetic Aperture Imaging" appeared in Applied Optics (July, 2009).
The article examined experimental results from a video-rate device. The device uses terahertz (THz) rays that emit a continuous narrow bandwidth radiation of 0.1 (THz). The instrument creates a twodimensional image of a point in an object. The image is reconstructed at a rate of 16 milliseconds per frame with a four-element detector array. The number of detectors, the configuration of the detection array and how well the baselines are calibrated affects the image resolution and quality.
"Scientists favor terahertz radiation because it can transmit through most non-metallic and non-polar mediums," said Federici. "When a terahertz system is used correctly, people can see through concealing barriers such as packaging, corrugated cardboard, walls, clothing, shoes, book bags, pill coatings, etc. in order to probe for concealed or falsified materials."
Once the rays penetrate those materials, they can also characterize what might be hiddenbe they explosives, chemical agents or morebased on a spectral fingerprint the rays will sense which can identify the material. terahertz radiation also poses minimal or no health risk to either the person being scanned or the THz system operator.
At this time, instruments using terahertz imaging are widely used in laboratories and have shown some limited use in commercial applications. However, a THz imaging system for security screening of people has no
|Contact: Sheryl Weinstein|
New Jersey Institute of Technology