Why CAN’T We Transmit Power Over the Air?

Wireless
transmission of power has been a dream of mankind, at least since Nicolas
Tesla dreamt of it a century ago.

Well, it turned out to be a tougher nut to crack than the atom. However,
ingenious scientists have developed a work-around: convert the electricity
into light, and then back to electricity.

First, a laser converts electricity into photons of light and beams
it to the plane or other vehicle. Then photovoltaic (light-collecting)
cells on the receiving end convert the photons back into electricity.

Although photovoltaic cells can capture sunlight on their own and turn
it into electricity, they do not do so particularly efficiently, said
David Bushman, a NASA scientist. They use only thin slices of sunlight’s
wide spectrum, so they waste 80 percent or more of the energy that they
collect.

Laser light, however, shines in very specific frequencies, not broad
bands, and when tuned right can give cells efficient energy doses.

from
the New York Times