Now, wireless power to charge your cellphones and laptops

Charging cellphones or laptops with electric wires and plugs may be a thing of the distant past soon.

London, June 8 : Charging cellphones or laptops with electric wires and plugs may be a thing of the distant past soon.

Researchers at the Massachusetts Institute of Technology (MIT), in the US, have reported that they can now send substantial amounts of power - enough to light a 60-watt bulb - across a room by magnetic induction between two devices tuned to resonate with each other.

This phenomenon of "strong coupling" can also be used to recharge or even run mobile devices wirelessly, they said.

Marin Soljacic, a theoretical physicist at MIT, knew from his experience with lasers, that objects that resonate at the same frequency readily exchange energy.

He set out to see if he could use electromagnetic resonance to transmit electrical power.

Together with his colleagues, he built a coil that naturally oscillates at 10 MHz when plugged to the mains.

However, unlike an antenna - which radiates the energy it receives - this device stores energy internally, in the form of oscillating currents and charges. The coil generates a strong electromagnetic field, most of which is trapped inside the coil, while an oscillating magnetic field surrounds it.

The oscillating magnetic field also efficiently transmits power across the lab to a receiver tuned to the same frequency, the scientists found.

However, as Soljacic said, minimising the external electric field is crucial for safety.

"We wanted to use the magnetic field for coupling, and have the electric field confined, because a magnetic field does not interact with most objects, including biological tissues," said theoretician Andre Kurs, a member of the MIT group,

The team believes though their invention will have real life applications, much work needs to be done before gadgets recharge themselves wirelessly.

"This technology will move from the lab to the real world. There's no fundamental problem. It's going to work," said Douglas Stone, a theoretical physicist at Yale University, not affiliated with the MIT group.

"I think it's brilliant. This is something anybody could have thought about for a century," he added.

The findings appear in the journal Science Express, reports New Scientist.

ANI