  Extraordinary optical transmission is observed due to the excitation of
surface plasmon polaritons (SPPs) in 2-Dimensional hexagonal anti-dot patterns
of pure Ni thin films, grown on sapphire substrates. A strong enhancement of
the polar Kerr rotation is recorded at the surface plasmon related transmission
maximum. Angular resolved reflectivity measurements under an applied field,
reveal an enhancement and a shift of the normalized reflectivity difference
upon reversal of the magnetic saturation (transverse magneto-optical Kerr
effect-TMOKE). The change of the TMOKE signal clearly shows the magnetic field
modulation of the dispersion relation of SPPs launched in a 2D patterned
ferromagnetic Ni film.
