Nanoscale all-optical plasmonic switching using electromagnetically induced transparency.

An all-optical switch composed of two interacting nanoparticles in front of an optical dielectric slab waveguide is proposed. An incident optical signal is coupled to the optical waveguide after scattering by the two nanoparticles. The scattered fields interfere constructively or destructively depending on the degree of optical transparency the nanoparticles induced by an optical control signal. The considered nanoparticles have a metallic core coated by an outer shell with three-level clusters such that the nanoparticles can exhibit electromagnetically induced transparency. A dipole-approximation model-based analysis reveals that a high rejection ratio can be achieved using the proposed configuration.