Enhanced magneto-optical Faraday effect in two-dimensional magnetoplasmonic structures caused by orthogonal plasmonic oscillations

We report the enhancement of the magneto-optical Faraday effect in a two-dimensional magnetoplasmonic grating with a square lattice. The structure consists of dielectric magnetic Bi-substituted iron garnet film with low thickness (100 nm) coated by a perforated gold layer. Enhancement of the Faraday rotation by about 2 times is shown experimentally and theoretically despite the suppression of the waveguiding modes. This happens primarily through excitation of surface plasmon polaritons propagating at the Au-garnet interface in two orthogonal directions along lattice vectors of the plasmonic grating.