[extropy-chat] non-radiative wireless energy

[Damien Broderick]

Maybe this is old news; certainly it's been a staple of sf since 
Heinlein's WALDO in the early '40s, if not before:

http://www.cosmosmagazine.com/node/849

Instead of irradiating the environment with electromagnetic waves, a 
power transmitter would fill the space around it with a 
'non-radiative' electromagnetic field. Energy would only be picked up 
by gadgets specially designed to 'resonate' with the field, and most 
of the energy not picked up by a receiver would be reabsorbed by the emitter.

While rooted in well-known laws of physics, non-radiative energy 
transfer is a novel application that no one seems to have pursued 
before. And figuring out the details was not easy, Soljacic said - 
something he and his colleagues did through theoretical calculations 
and computer simulations.

"It certainly was not clear or obvious to us in the beginning how 
well it could actually work, given the constraints of available 
materials, extraneous environmental objects, and so on. It was even 
less clear to us which designs would work best," said Soljacic.

With the proposed designs, non-radiative wireless power would have 
limited range, but Soljacic and colleagues calculate that an object 
the size of a laptop could be recharged within a few metres of the 
power source. Placing one source in each room would be sufficient for 
coverage throughout your home.

Wireless energy could also be adapted to industrial applications, for 
example powering freely-roaming robots within a factory.