Recharging your laptop computer or your cell phone
might one day be done the same convenient way many people now surf
the Web---wirelessly. At this week's AIP Industrial Physics Forum,
in San Francisco, Marin Soljacic (MIT) spoke about how energy could
be transferred wirelessly by the phenomenon of induction, just as
coils inside power transformers transmit electric currents to each
other without touching. The idea of wireless energy transfer is not
new. Nikola Tesla was working on the idea more than a century ago
but failed to develop a practical method.
In the new MIT scheme, a power transmitter would fill the space around
itself with a non-radiative electromagnetic field -- meaning that its
energy would not ripple away as electromagnetic waves. Energy would
only be picked up by appliances specially designed to resonate with
the field; most of the energy not picked up by a receiver would be
reabsorbed by the emitter.
Contrary to more traditional, radiative means of energy transmission
such as microwaves, it would not require a direct line of sight. It
would be innocuous to people exposed to it. With designs proposed by
Soljacic in a paper with Aristeidis Karalis and John Joannopoulos,
an object the size of a laptop could be recharged within a few meters
of the power source.
and his MIT colleagues are now working on demonstrating the technology
Contact Marin Soljačić