Terahertz rays beam past hype
A new range of frequencies have a host of applications, from medicine to security
Michael Pollitt
Thursday May 11, 2006
The Guardian
Professor Malcolm Dunn of St Andrews University is a keen photographer. But in his physics laboratory is a different sort of camera. His compact terahertz laser, which works like an x-ray but without the health risks, can see through thin layers and even identify what is underneath. Terahertz frequencies lie between microwaves at the low end, and the infrared end of the visible spectrum at the top end. Within this range, “a lot of materials are transparent - cloth, paper, plastics and human tissue. At the same time, large molecules have characteristic spectra,” says Dunn.
Seven years ago, “terahertz rays” were touted as a replacement for dental x-rays, but they have yet to make it into your dentist’s surgery. Recent reports of shoebox-sized scanners for drugs and explosives also promise easier law enforcement.
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