WOULDN’T it be great if your cellphone or laptop started to charge as soon as you walked into your house of office? A phenomenon called “evanescent coupling” could make charging your electronic gadgets this easy.
Researchers have been looking for a wireless charger for some time. One idea is to use electromagnetic induction – passing an electric current through a coil to create a magnetic field that induces a current in a neighbouring coil. This is the way devices like electric toothbrushes are charged, and has been proposed as the basis of a universal re-charger pad before (New Scientist, 22…
