Magnetic energy harvesting and concentration at a distance by transformation optics.

Based on transformation optics, we introduce a magnetic shell with which one can harvest magnetic energy and distribute it as desired in space with unprecedented efficiency at an arbitrary scale. It allows a very large concentration of magnetic energy in a free space region, which can be used for increasing the sensitivity of magnetic sensors, and the transfer of magnetic energy from a source to a given distant point separated by empty space, with possible applications in wireless transmission of energy.