Scanning at Terahertz can detect hidden weapons

Physicists patented Terahertz Imaging system capable of detecting and Imaging Hidden Weapons.

John Federici Phd Professor, department of physics, New Jersey Institute of Technology along with other scientists at NJIT received U.S.
patent for Terahertz Imaging system and Method. This invention relates generally to imaging apparatus and methods, and more specifically relates to imaging systems and methods which utilize electromagnetic radiation in the Terahertz (THz) range as incident energy at objects to be examined.

Federici believes that Terahertz Imaging system is of a fundamental use in detecting and imaging concealed materials (weapons) and can be a ultimate defence against terrorism. “I see the Terahertz spectrum as one of the critical technologies for defence against suicide bombers and other terrorist activities,” Federici said.

John Federici and his research team (Westfield, N.J. (US); Robert Barat, Franklin Park, N.J. (US); and Dale E. Gary, Berkely Heights, N.J.
(US)) studied effect of synthetic aperture imaging on rays with terahertz frequency. “The idea has been to apply different methods of imaging to Terahertz rays,” said Federici. He further added “The advantage of this particular method is the ability to generate Terahertz images with a large number of pixels using a limited number of Terahertz detectors. This imaging method should also be capable of video-rate imaging, thereby enabling the real-time monitoring of people hiding concealed explosives or other dangers.” So a typical terahertz system would be like a see through video camera showing images at real time. One can think of security camera's with CIA and FBI shown in hollywood movies.

Scientist in the field of imaging systems work mostly on radiation with frequency in Terahertz range because of their capability of
transmitting through non-metallic and non-polar mediums (material with no electrostatic attraction / insoluble). Once the radiations penetrate through such mediums synthetic aperture imaging technique can draw pictures based on the radiation detection and this all can happen real time in a ideal system.

Once the rays penetrate those materials, they can also characterise what might be hidden –be they explosives, chemical agents or more—based 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. The Terahertz system is patented with US patent office under patent number 6815683 US 6,815,683 B2 Terahertz imaging system and method.

1. Terahertz imaging apparatus for examining a region of interest to determine the presence of a specified composition; comprising:
(a) means for generating electromagnetic radiation of a desired terahertz frequency suitable for said examining;
(b) means for rendering said terahertz radiation incident at said region of interest;
(c) detector means comprising an interferometric array of spaced detectors for simultaneously detecting at a plurality of points in a detector plane spaced from said region of interest the terahertz radiation reflected from or transmitted through said region; and
(d) means for converting the said detected terahertz radiation to an image of said region of interest from which the presence of said
specified composition is determinable.

Federici and his team recently published “Terahertz imaging and sensing for security applications explosives, weapons and drugs,” in
Semiconductor Science and Technology (Vol 20, page 266, 2005). The U.S. Department of Homeland Security, Army Research Office and National Science Foundation have provided funding for this research since 2002.

The article focused on three configurations of Terahertz systems, examining when and how best to use the rays. Transmission versus reflective detection, pulsed Terahertz detection systems versus continuous wave systems, and close proximity versus stand-off detection are compared.

“While pulsed Terahertz detection systems are capable of close proximity detection,” said Federici, “there are many factors to take into
account. For example, distortions to Terahertz pulses introduced by propagation through the atmosphere, favor a continuous wave system for stand-off detection.”

Terahertz Imaging technique is quite famous since 1995 and its quite into discussion arena of physicists as new sophisticated devices helping scientists to discover the full potential of the Terahertz imaging technique. John Federici is recently getting praise for his work in the field and his work is getting highly appreciated as ultimate defence against terrorism.