TERAHERTZ SENSING SEES THE INVISIBLE
Contacts: Xi-Cheng Zhang, (518) 276-3079, [email protected], or www.rpi.edu/~zhangx2; Michael Shimazu, MOEC, (518) 270-8203, [email protected], or www.automatrix.com/moec
A scientific breakthrough that could eventually become as important as X-ray and radar technologies may soon make it possible to see images of diseased tissue, electric fields, plastic explosives hidden in a suitcase, and much more that is undetected by other imaging systems. Called real-time electro-optic terahertz sensing, the technology was invented under the leadership of Xi-Cheng Zhang, associate professor of physics at Rensselaer Polytechnic Institute.
With a frequency of more than a trillion cycles per second, terahertz signals occupy an extremely large portion of the electromagnetic spectrum between the infrared and microwave bands. Just as we can use visible light to create a photograph, inaudible radio waves to transmit music and speech, or invisible radiation to reveal broken bones, terahertz radiation can also be used to create images or communicate information.
Until now, no technology existed that could use this radiation to rapidly create images, said Zhang. Imaging work performed by Bell Labs can create images in the terahertz range, but not in real time. The Rensselaer detector can create an instantaneous image of 250,000 pixels.
The unique detector features a zinc telluride crystal onto which the terahertz radiation is focused after flowing through the target material. At the same time, a laser ìreadoutî beam is directed into the system and used to convert the spatial and temporal (spectral) distributions into visible images that can be captured by a video camera linked to a computer.
The Rensselaer technology has been licensed exclusively for development by Molecular OptoElectronics Corporation (MOEC) of Watervliet, N.Y. Under the agreement, Rensselaer and MOEC will collaborate in developing and commercializing imaging systems that use terahertz radiation.
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