Wireless Power Transmission

Farewell, wires? Power beamed through air

‘WiTricity’ can light up lamps and laptops; system touted as safe, efficient

Power cables and even batteries might become a thing of the past using a new technique that can transmit power wirelessly to cell phones, laptops, MP3 players, household robots and other electronics.

Scientists lit a 60-watt light bulb from a power source 7 feet (2 meters) away with their new technique, with no physical connection between the source and the appliance. The researchers have dubbed their concept "WiTricity," as in "wireless electricity."

Soljacic and his colleagues devised WiTricity based off the notion of resonance. One well-known example of resonance can be seen when an opera singer hits the right note to cause a champagne glass to resonate and shatter. Two objects resonating at the same frequency tend to exchange energy efficiently, while interacting weakly with objects not resonating at the same frequency.

Instead of sound, the MIT physicists focused on magnetic fields. Most common materials interact only very weakly with magnetic fields, so little power would get wasted on unintended targets. "The fact that magnetic fields interact so weakly with biological organisms is also important for safety considerations," said Soljacic's colleague, MIT physicist Andre Kurs.