MIT researchers have successfully tested a system that delivers power to electronic devices wirelessly.

The researchers have successfully sent a beam of electricity, like a radio wave, between two points, using the broadcast to power a 60-watt light bulb. The team lit up the bulb from a power source seven feet away, with no physical connection between the two points. The project has been dubbed WiTricity, for wireless electricity.

The experiment demonstrates the concepts the research team outlined in a paper last fall. The power transfer has a limited range. "Still, for laptop-sized coils, power levels more than sufficient to run a laptop can be transferred over room-sized distances nearly omni-directionally and efficiently...even when..objects completely obstruct the line-of-sight between the two coils," said the researchers.

A WiTricity laptop in a room with a transmitter unit would charge automatically, without having to be plugged in, and would run without having a battery.

The technique is somewhat similar to magnetic induction, used in power transformers that have coils very close to each other to transmit power between them. But as the distance increases, these non-resonant coils become vastly less efficient, according to the researchers.

More details of the experiment are in the 7 June online edition (access to full paper requires paid subscription or per-article fee) of ScienceExpress, the pre-publication venue for Science Magazine.

The project team includes MIT professors and graduate students: Professor Peter Fisher, John Joannopoulos, Aristeidis Karalis, Andre Kurs, Robert Moffatt, and Professor Marin Soljacic. The research has been funded by the Army Research Office (via MIT's Institute for Soldier Nanotechnology), the National Science Foundation and the Department of Energy.