Time reversal technique sheds light on future

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(Phys.org)—Imagine a cell phone charger that recharges your phone remotely without even knowing where it is; a device that targets and destroys tumors, wherever they are in the body; or a security field that can disable electronics, even a listening device hiding in a prosthetic toe, without knowing where it is.

While these applications remain only dreams, researchers at the University of Maryland have come up with a sci-fi seeming technology that one day could make them real. Using a time-reversal technique, the team has discovered how to transmit power, sound or images to a nonlinear object without knowing the object's exact location and without affecting objects around it. Their work, "Nonlinear Time Reversal in a Wave Chaotic System," was published in the Feb. 7 issue of the Physical Review Letters journal. "That's the magic of time reversal," says Steven Anlage, a university physics professor involved in the project. "When you reverse the waveform's direction in space and time, it follows the same path it took coming out and finds its way exactly back to the source."

http://phys.org/news...ors-future.html

[StarMountainKid]

All this is new to me but interesting. This quote explained the process for me.

Phys.org)—In spite of its name, the time reversal of a wave doesn't involve sending the wave back in time, but for scientists, the process is almost as compelling. After a source generates a wave, the wave propagates through a medium and is recorded at a few points in its surroundings by an optical method. Then, the wave is re-emitted in a way so that its energy focuses back at the initial source position, as though the wave were being played backwards. Because the wave precisely retraces its original path as it travels back to its source, its mathematical description is reversed in time but is otherwise exactly the same.

http://phys.org/news/2012-08-physicists-reversal.html

Edited February 25, 2013 by StarMountainKid