Nonlinear metal-dielectric nanoantennas for light switching and routing

We introduce a novel hybrid metal-dielectric nanoantenna composed of dielectric (crystalline silicon) and metal (silver) nanoparticles. In such a nanoantenna, the phase shift between the dipole moments of the nanoparticles, caused by differences in the polarizabilities, allows for directional light scattering; while the nonlinearity of the metal nanoparticle helps to control the radiation direction. We show that the radiation pattern of this nanoantenna can be switched between the forward and backward directions by varying only the light intensity around the level of 6MWcm ^-2, with a characteristic switching time of 40 fs.