Optical transmission through metal films with a subwavelength hole array in the presence of a magnetic field

In a recent paper Ebbesen et al. [Nature (London) 391, 667 (1998)] reported on extraordinary optical transmission through periodic hole arrays in metallic films. They explain this by the coupling of light with surface plasmons. Continuing this idea, we have studied such systems in the presence of a static magnetic field. The problem is treated in the quasistatic limit, i.e., when the wavelength is larger than the hole sizes and the array period. We find that the frequency of the transmission peak depends strongly on both the magnitude and the direction of the applied in-plane magnetic field. The directional sensitivity results in a magneto-induced anisotropy of the optical properties of such systems, even for hole arrays with square or triangular symmetry.