UK-developed Terahertz sensor could improve airport security

Called ‘Q-Eye’, the invention senses radiation across the spectrum between microwaves and infra-red, known as the Terahertz (THz) region of the spectrum. According to its developers at the University’s physics department it works by detecting the rise in temperature produced when electromagnetic radiation emitted by an object is absorbed by the sensor, even down to the level of very small packets of quantum energy (a single photon).

The patented device involves a thin film of aluminium deposited on top of a silicon layer placed under strain, used to create an electronic cooling (e-cooling) process. The electrons in the silicon layer are so isolated from the silicon lattice they become highly sensitive to incoming radiation. This  “e-cooling” process is the secret to Q-Eye sensor’s ability to carry out rapid imaging and material identification the team claims.

What’s more, the device can be made using standard silicon processes, enabling large numbers of detector chips containing designs matched to a particular application to be fabricated on large (300mm) wafers with great uniformity.

Commenting on the development Prof Evan Parker, one of the leaders of the project said: “We were very surprised when our first very crude prototype showed such impressive speed and detection performance and our initial calculations indicated world-beating detector capability – all this and using silicon.”

Parker and his colleague Prof Terry Whall are now hoping to commercialise the device through spin-out company Q-Eye Ltd. They claim that it could help address the weaknesses reported earlier this month in America’s airport security, where mock weapons and explosives were smuggled through airports, undetected in 95% of cases. It may also prove useful in discovering concealed goods in the retail industry or for non-destructive monitoring, for example quality control in drugs or food.