Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo

 

Unsupported browser: Your browser does not meet modern web standards. See how it scores »

Researchers at the University of Utah have found a way to control terahertz radiation with more precision than ever before, potentially laying the foundation for a new breed of wireless devices that can take advantage of the previously untapped frequencies. Although still years from commercialization, routers and receivers that use terahertz radiation–which technically ranges from about 100 gigahertz to 10 terahertz–could eventually pack more data onto airwaves, speeding up wireless Internet links a thousand times, says Ajay Nahata, a professor of electrical and computer engineering who led the research.

Nahata and his team designed a perforated stainless steel film that is able to selectively allow certain terahertz frequencies to pass through and cancel out others. In effect, the researchers have built a simple terahertz filter, a potential precursor to terahertz communication devices.

Most wireless gadgets use radiation in the microwave frequency; Wi-Fi, for instance, operates at 2.4 gigahertz. At this frequency, technologies such as radiation sources, detectors, and modulators (devices that encode data on the waves) are well established. But currently, efficient terahertz sources and detectors are still being developed, and “there are effectively no real devices to manipulate those frequencies,” says Nahata. “Because of this, terahertz is the gap in the electromagnetic spectrum. We’re making new devices so terahertz can be useful.”

The benefits of terahertz communication could be great. A typical modulator for a 2.4-gigahertz signal can only encode information at far lower frequencies–at about 50 megahertz. But a 2.4-terahertz wave oscillates a thousand times faster than a 2.4 gigahertz signal, and correspondingly, if terahertz modulators could be made, the modulated signal would also be a thousand times faster, says Nahata. These terahertz waves would be most useful for relatively short-range communication such as within a room, he says, because over greater distances, the signal dies off.

The researchers’ new device is essentially a stainless steel metal film with arrays of holes in it. When a terahertz source shines on the film, the radiation gets trapped on its surface. In effect, the energy from the terahertz radiation is converted from a three-dimensional electromagnetic wave to a two-dimensional surface wave, called a plasmon. Nahata explains that as these surface waves move about the film, they can bump into structures on the surface such as troughs and holes. At the holes, he says, the waves constructively interfere, meaning that there is a buildup of light; the energy of the plasmons passes through the holes and is essentially converted back into three-dimensional terahertz radiation, once on the other side of the film. The specific frequency of light that is emitted depends on the spacing of the holes.

2 comments. Share your thoughts »

Credit: Tatsunosuke Matsui, University of Utah

Tagged: Communications, wireless, radiation, communications, Wi-Fi, microwaves

Reprints and Permissions | Send feedback to the editor

From the Archives

Close

Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me
×

A Place of Inspiration

Understand the technologies that are changing business and driving the new global economy.

September 23-25, 2014
Register »