Metal-coated magnetic nanoparticles in an optically active medium: A nonreciprocal metamaterial

Plasmonics allows light to be localized on length scales much shorter than its wavelength, which makes it possible to integrate photonics and electronics on the nanoscale. Magneto-optical materials are appealing for applications in plasmonics because they open up the possibility of using external magnetic fields in plasmonic devices. Here, we fabricate a new magneto-optical material, a magnetoplasmonic crystal, that consists of a nanostructured noble-metal film on top of a ferromagnetic dielectric, and we demonstrate an enhanced Kerr effect with this material. Such magnetoplasmonic crystals could have applications in telecommunications, magnetic field sensing and all-optical magnetic data storage.

We demonstrate theoretically the existence of one-way electromagnetic modes in a waveguide formed between a semi-infinite photonic crystal structure and a semi-infinite metal region under a static magnetic field. Such a waveguide provides a frequency range where only one propagating direction is allowed. In this frequency range, disorder-induced scattering is completely suppressed. Such a waveguide also modifies the basic properties of waveguide-cavity interaction.