  We examine here the anomalous optical response of a nanosphere composed of
two conjoined hemispheres of different materials, one of them being plasmonic.
At the internal resonance, we show how the light interaction becomes
dramatically dependent on the polarization of the local electric field exciting
the particle. In particular, its response may be varied from the one of an
ideal perfect electric to a perfect magnetic homogeneous sphere through all the
possible intermediate stages, by a simple 90 deg rotation. Applications as
optical switch and as a novel nanocircuit element are envisioned.
