Terahertz Technology Opens Many Possibilities

Two recent stories indicate the progress that has been made in reducing the cost of terahertz technology. This technology is interesting, as it can penetrate clothes (used in the scanners you walk through at the airport), walls, and skin. Terahertz wavelengths are much shorter than the smallest microwave/millimeter wavelengths and provide relatively high-resolution images without the ionizing radiation associated with X-rays.

A research team at the Texas Analog Center of Excellence believes New Research Could Mean Cellphones That Can See Through Walls. Dr. Kenneth O, director of the Center of Excellence and a professor of electric engineering at UT Dallas said, "We've created approaches that open a previously untapped portion of the electromagnetic spectrum for consumer use and life-saving medical applications. The terahertz range is full of unlimited potential that could benefit us all."

These approaches include a simpler way of creating terahertz signals and, most important for consumer devices, using CMOS technology to receive/image these signals. Dr. O explained, "CMOS is affordable and can be used to make lots of chips. The combination of CMOS and terahertz means you could put this chip and a transmitter on the back of a cell phone, turning it into a device carried in your pocket that can see through objects."

Other applications for terahertz imaging include detecting cancer tumors, diagnosing diseases through breath analysis, and monitoring air quality. Perhaps a terahertz source and imager could become a key part of a future device similar to Star Trek's Tricorder.

IEEE Spectrum has a more critical look at terahertz imagers in its April issue-- A Cheap Terahertz Camera: CMOS detectors could drive down the cost of terahertz imaging, though difficulties remain. The IEEE Spectrum article focuses on research at IEMN and STMicroelectronics in France and the University of Wuppertal, in Germany. The article describes a high-res terahertz camera: "With just 1024 pixels, this new transistor-based camera is unlikely to give a high-resolution window into the unseen terahertz realm. But the advance has researchers excited, because it suggests terahertz technologies may soon get a lot cheaper and more accessible. The single-pixel terahertz detectors in use now can easily cost as much as U.S. $10 000, Siegel says, so developing a detector that could be mass-produced by chip manufacturers represents a significant advance."

Terahertz technology is interesting not only because of its electromagnetic properties make it useful for imagining and material/biological analysis but because it could serve as a very high speed, very short range, data link. This could be useful in congested areas where lower frequency spectrum is scarce.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.