MIT demos wireless power transmission...

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Research could free cellphones, portable electronics from wired charging..
Last year MIT physicists presented one theoretical approach to such a future. Now they have demonstrated it, lighting a 60-watt light bulb from a power source seven feet (more than two meters) away.
The work was reported in the June 7 issue of Science Express, the advance online publication of the journal Science.
Various methods of transmitting power wirelessly have been known for centuries. Perhaps the best-known example is electromagnetic radiation in the form of radio waves. But while such radiation is excellent for wireless transmission of information, it is very inefficient for power transmission. Since radio waves spread in all directions, a vast majority of the power from such a source would be lost to the environment.

Then Soljacic thought about the phenomenon behind electric motors and power transformers. These devices contain coils that transmit energy to each other by electromagnetic induction: a current running in an emitting coil induces another current in a receiving coil.

He realized that something similar could potentially transfer energy over longer distances. A power transmitter would fill the space around it with a "nonradiative" electromagnetic field. Energy would only be picked up by gadgets specially designed to "resonate" with the field. Most of the energy not picked up by a receiver would be reabsorbed by the emitter. WiTricity is based on that concept.

Two objects of the same resonant frequency tend to exchange energy efficiently. A child on a swing is a good example of mechanical resonance.

The MIT team focused on magnetically coupled resonance, which is particularly suitable for everyday applications because most common materials interact very weakly, if at all, with magnetic fields. As a result, interactions with objects other than the transmitter and receiver are suppressed even further, making the system that much more efficient. "The fact that magnetic fields interact so weakly with biological organisms is also important for safety considerations".

The MIT system uses two copper coils, each a self-resonant system. One of them, attached to the power source, is the sending unit. It fills the space around it with a non-radiative magnetic field. That nonradiative field mediates the power exchange with the other, receiving coil, specially designed to "resonate" with the field.

With such a design, power transfer still has a limited range. But the researchers expect that power levels more than sufficient to run a laptop can be transferred over room-sized distances, even when environmental objects completely obstruct the line of sight between the two coils.

"As long as the laptop is in a room equipped with a source of such wireless power, it would charge automatically, without having to be plugged in. In fact, it would not even need a battery to operate inside such a room."

WiTricity is rooted in well-known laws of physics. I think its a great to work upon.