Metal Films Enable New Terahertz Technology
March 30, 2007
Terahertz frequencies lie just below infrared in the electromagnetic spectrum. Since terahertz wavelengths are shorter, they can provide higher resolution than microwaves or millimeter waves when used for medical imaging, without causing the cell damage possible with even shorter wavelength x-rays. Terahertz signals can also handle extremely high data rates. However, until now it was difficult to generate pure terahertz signals. Using metal films with holes one-quarter to one-half millimeter in diameter--smaller than the wavelength of far-infrared light--researchers at the University of Utah found certain terahertz frequencies were completely transmitted through the film even though the radiation had wavelengths larger than the holes.
The study was conducted by Ajaj Nahata, associate professor of electrical and computer engineering, and principal author Z. Valy Vardeny, a distinguished professor of physics, along with Tatsunosuke Matsui, a post doctoral researcher in physics and Amit Agrawal, a doctoral student in electrical and computer engineering. All of them are associated with the University of Utah.
"We found a way to manipulate a form of infrared radiation that is not now used for communications so that, in the future, it may be possible to use it for high-speed, short-range communication between computers and other devices," Nahata said. "Terahertz is a new region of the spectrum for communications, because the rest of the spectrum is crowded with communication and broadcasting signals. Vardeny added, "Industry is starving for more electromagnetic frequencies," yet terahertz frequencies are unexplored. They are too high for electronics and there are technical obstacles in generating, manipulating and detecting terahertz radiation."