Wednesday, July 25, 2007

This is HUGE

This is a major breakthrough, although I doubt we will see any commercial items using this technology for a number of years. Wireless power would have a MAJOR effect upon electronics as we know it.

The Power of Induction: Science News Online, July 21, 2007
When Soljacic first presented the principle, it was unproved. All he could show were his calculations. "I expected that some people would think I was a crackpot," says Soljacic, a physicist at the Massachusetts Institute of Technology (MIT). "This was pretty far out."

Perhaps it also didn't help that the participants at the symposium—a celebration of the 90th birthday of Charles Townes, who pioneered the laser in the 1950s—included 18 Nobel prize winners and dozens of other luminaries. Much to Soljacic's relief, he sold the scientists on his presentation.

A year and a half later, a bulb lit up in an MIT lab—unplugged. Soljacic and his collaborators had demonstrated a new way of coaxing magnetic fields into transferring power over a distance of several meters without dispersing as electromagnetic waves. The demonstration ushered in a technology that might eventually become as pervasive as the gadgets it could power. Laptops, cell phones, iPods, and digital cameras might someday recharge without power cords. With the proliferation of wireless electronics, perhaps it was just a matter of time before power transmission would go wireless, too.

The device that Soljacic and his collaborators put together had a disarming simplicity. On one side of the room, hanging from the ceiling, was a ring-shaped electrical circuit, about half a meter across, plugged into the wall. Hanging adjacent to the circuit, but with no physical connection to it, was a slightly larger copper coil looking like an oversize mattress spring. A few meters away hung a similar system with an ordinary lightbulb attached to the circuit. When the physicists sent power through the first circuit, the bulb lit up.

As expected, some energy was lost on its way to the lightbulb. However, a surprising amount reached its destination, the team reports in the July 6 Science. "The efficiency was 40 percent at the biggest distance we probed [more than 2 meters]," Soljacic says. At shorter distances, the efficiency was much higher.

The coils of this demonstration device would be too big to fit inside a laptop, let alone a cell phone. But this was only the first and simplest of several prototypes that the physicists have in mind. More tests are to come. The MIT team and other physicists say that in principle they see no obstacle to making such devices more compact and more efficient.