Versatile terahertz technology could help aircraft to land

Technology used in controversial airport body scanners could help aircraft land in poor visibility or power high-bandwidth communication systems, says a new U.K. company.

Teratech Components, a recent spinout from the Science and Technology Facilities Council (STFC), this week received a £10,000 prize from Research Councils U.K. to exploit new commercial applications for the firm’s terahertz radiation devices.

Terahertz scanners detect a type of high-frequency electromagnetic radiation emitted by anything with temperatures higher than around 10 kelvin. It can penetrate dry, non-metallic materials such as clothing or sand, but is absorbed by water and metal (see “Researchers demonstrate highly directional Terahertz laser rays,” 9 August 2010 HSNW; and “Remote terahertz scanners could, in theory, see what is in your pockets from miles away,” 15 July 2010 HSNW).

This allows the scanners to create computer images of people’s bodies that reveal items hidden under their clothing — an application that has attracted criticism since it started being used in airports in the United Kingdom and the United States earlier this year.

Stephen Harris quotes Teratech’s Dr. Byron Alderman to say that Teratech hopes to sell its version of the technology that emits and detects terahertz radiation to companies wanting to use it for other purposes. “Instead of trying to do those applications ourselves, we’re leaving it to our customers,” he said. “We’re creating the fundamental detector technology that allows these other applications to be generated.”

Terahertz devices were first used in astronomy to see through interstellar dust. Alderman suggested it could be used in a similar way to help pilots see through the dust created when landing a helicopter in the desert, acting as a kind of radar to locate the ground where lasers would be dispersed by the particles.

The radiation would also have an advantage over traditional radar signals because it can create a 3D model of an object it is tracking, as well as providing information about its location.

The signal is emitted at a high frequency between 100 gigahertz and a few terahertz and is found between the infrared and microwave parts of the electromagnetic spectrum.

Its high frequency allows it to transmit large amounts of data, although this would only likely be used as part of a local-area network because of its tendency to be absorbed by buildings.

There are several companies working in the field and several ways of generating the radiation, including using short-pulse lasers. Teratech uses specially developed Schottky diodes that operate at room temperature rather than under cryogenic conditions like some competitors.

“They’re at a really difficult size to make — about a quarter of the width of a human hair,’ said Alderman. ‘You’re between technologies: you’re using a technology designed to make very small structures to make things that are a bit bigger.”