Terahertz imaging provides high-resolution scans of people and objects without the radiation hazards associated with X-rays. T-rays are also responsiive to differences in material composition, which makes them useful for detecting tumors and counting the change in your pocket.
Terahertz frequencies are tough to produce and detect. They're higher than microwaves but lower than infrared light. "You're never sure whether to use electronics-based or optics-based" technology, says Martyn Chamberlain of the University of Leeds in England, a leading terahertz researcher. The terahertz sources now on the market tend to emit many frequencies at once, limiting their utility. In the past year, however, several research projects have made substantial progress in developing devices that produce t-rays within a narrow frequency band--a requirement for precise chemical sensing and medical imaging. Full article here. Props, once again, to Boing Boing.
