Laser Phone Charging...

A new laser system can wirelessly recharge phones from across the room(Credit: Mark Stone/University of Washington)

Topics: Applied Physics, Electrical Engineering, Electronics, Laser

We've cut the cord for communication, thanks to Bluetooth and Wi-Fi, but charging our little pocket supercomputers still takes a tether. Judging by the range of wireless charging technologies in the works, that might not be the case for much longer. A team from the University of Washington has demonstrated how lasers could be used to charge a device from across the room.

The team mounted a power cell on the back of a smartphone and hit it with a narrow laser beam in the near-infrared part of the spectrum. From a distance of 4.3 m (14 ft), the laser was able to deliver 2 W of power to a 97-sq cm (15-sq in) area, charging the phone about as quickly as a regular old USB cable.

The laser emitter is designed to automatically sense when a phone is ready to be charged, while the smartphone was programmed to send out high-frequency "chirps" inaudible to the human ear that tells the emitter where it is.

"This acoustic localization system ensures that the emitter can detect when a user has set the smartphone on the charging surface, which can be an ordinary location like a table across the room," says Vikram Iyer, co-author on a study describing the device.

Laser system wirelessly charges phones from across the room, Michael Irving, New Atlas