50Gbps
They could dramatically speed up Wi-fi and even save lives
Data-transfer speed of terahertz waves
What are they?
High-frequency radiation waves that can transmit data at 50 gigabits per second (Gbps), 100 times faster than today’s Wi-fi. A recent breakthrough suggests it could become mainstream sooner than previously thought.
What happened?
US researchers sent video signals using terahertz waves (sometimes called T-waves), rather than slower microwaves, which are currently used to carry wireless signals. Professor Daniel Mittleman (pictured), who led the research at Brown University in Rhode Island, said it was the first time anyone had sent terahertz waves by “multiplexing” (as beautifully captured in the image opposite).
What’s that?
It’s when multiple signals are sent through a single channel, such as TV channels on one cable, or hundreds of users on a Wi-fi network (which means, for example, that emails you send won’t get mixed up with those sent by other people). Professor Mittleman demonstrates it on Youtube at www.snipca.com/25505.
What would I be able to do with it?
Download and stream entire films in seconds, wherever you are. But the faster you send data, the greater the chance errors will creep in, corrupting the video. Professor Mittleman said that during his test errors appeared when sending data at 50Gbps. This isn’t disastrous though. Such errors are within the range that can be fixed by today’s communications networks.
How soon will we be using it?
It’s a way off. While the experiments were successful, none of the hardware needed for terahertz Wi-fi exists yet. Also, we’ll have to wait for authorities to allocate space for terahertz Wi-fi on the mobile spectrum. Professor Mittleman concedes that “companies are going to be reluctant to develop terahertz technologies until there’s a serious effort by regulators to allocate frequency bands for specific uses”.
But he recently received a licence to perform outdoor tests at terahertz frequencies on the Brown University campus, so things are progressing.
Do we need to have more spectrum space?
Yes. With billions of devices worldwide using Wi-fi, demand for data is outstripping capacity. Terahertz waves could solve this problem because their frequencies can carry more data.
What else can terahertz waves be used for?
Many things, according to scientists, including reading closed books. Researchers at the Massachusetts Institute of Technology have used waves to ‘read’ letters printed on sheets of paper. Museums said they could use this technique to read ancient books that are too fragile to handle. These ‘non-invasive’ methods, which see through objects, might also be used to save lives.
How?
By detecting the early stages of iron corrosion in concrete, helping engineers to spot buildings, roads and bridges that need reinforcing. Meanwhile, Japanese scientists have built a wearable device that can see through the human body to potentially scan cancer cells, blood clots and sweat glands (pictured left).
So it’s a kind of ‘x-ray vision’?
In a way, yes, which has prompted privacy concerns. In 2012 scientists in Texas showed how a phone’s camera could use terahertz waves to take photos through clothes. But to work, the phone needs to be up close to the subject – no more than 10 centimetres away. That would be too near for Peeping Toms to use discreetly, thankfully.