TERAHERTZ rays, or T-rays, are unique. Squeezed into the electromagnetic spectrum between infrared radiation and microwaves, they can pass through walls, clothes and a few millimetres of skin – without the damaging effects of X-rays. These talents raise the prospect of creating scanners that could allow police to “see” into besieged buildings, airport staff to check for concealed weapons and doctors to detect the extent of skin cancers (Â鶹´«Ã½, 30 August, p 11).
Terahertz images of concealed guns and explosives are remarkable for their clarity, as TV viewers in the UK had the chance to see this week in…
