Tuning the extraordinary optical transmission through subwavelength hole array by applying a magnetic field.

The transmission of light through a thin Ag film with a periodic subwavelength hole array can be influenced by the presence of the externally applied magnetic field H. Using a three-dimensional finite element method, we show that the spectral locations of the transmission peak resonances can be shifted by varying the magnitude and direction of the H. The transmission peaks have blueshift, and the higher the magnitude of H the larger the blueshift. The shift is due to the change of cavity resonance condition as a result of the magneto-induced anisotropy in the optical properties of the Ag film. Hence, high transmittance for any desired wavelength can be achieved by applying an appropriate H to the metallic film of optimized material and hole parameters.