  We report on significant enhancement of the magnetooptical effects in
gyrotropic systems of a metallic film perforated by subwavelength hole arrays
and a uniform dielectric film magnetized perpendicular to its plane.
Calculations, based on a rigorous coupled-wave analysis, demonstrate the
Faraday and Kerr effect spectra having several resonance peaks in the near
infrared range, some of them coinciding with transmittance peaks. Qualitative
analysis revealed that magnetic polaritons being coupled magnetic-film
waveguiding modes with surface plasmons play a crucial role in the observed
effect.
