The strength of the magnet field diminishes with distance, but scientists at Duke University and Mitsubishi are developing what they call a "superlens" that will focus the field on a specific target, thus improving efficiency. The lens made it possible to wirelessly light up a light bulb six feet away.
Incidentally, several cell phone companies have offered wireless recharging capability in their phones in recent months, but according to the manager of one large retail outlet, the first effort left much to be desired.
In some cases, the rapid rate of charge was so intense that it fried the batteries, he said. The next generation of plug-free phones should be out fairly soon, and hopefully they will work better.
One exciting area of research involves the use of wireless energy transfer in devices for biological systems. Mechanical pumps and pacemakers for human hearts have saved an untold number of lives, but currently they have to be recharged, or their batteries replaced, and that requires a wire sticking out of the chest, or surgery, both of which can lead to infections that cause 40 percent of the patients to return to hospitals. And that can be fatal.
But researchers at the University of Washington and the University of Pittsburg Medical Center are developing a way to focus the power so tightly that it can be applied to an organ deep within the body without losing much efficiency as it moves through the tissue. Thus no wires, and thus fewer returns to the hospital.
It's just too bad that Tesla isn't around to see this reaffirmation of his theories. As much a showman as a scientist, Tesla emigrated to the United States in 1884 and while he was clearly brilliant, sometimes he must have been hard to take seriously.
During his effort to create artificial lightning near Colorado Springs, residents there were startled to see sparks jumping between their feet as they walked along the streets. His experiments made the soil so hot that the locals complained bitterly.
He made a lot of money from his many inventions, but he used nearly all of it on experiments and spent the last few years of his life drifting from one hotel to another in New York City. He still held occasional press conferences to show off his work, but he died alone in 1943 at the age of 87.