  The excitation of surface plasmons in magnetic nano-structures can strongly
influence their magneto-optical properties. Here, we use photoemission electron
microscopy to map the spatial distribution of the electric near-field on a
nano-patterned magnetic surface that supports plasmon polaritons. By using
different photon energies and polarization states of the incident light we
reveal that the electric near-field is either concentrated in spots forming a
hexagonal lattice with the same symmetry as the Ni nano-pattern or in stripes
oriented along the $\Gamma$-K direction of the lattice and perpendicular to the
polarization direction. We show that the polarization-dependent near-field
enhancement on the patterned surface is directly correlated to both the
excitation of surface plasmon polaritons on the patterned surface as well as
the enhancement of the polar magneto-optical Kerr effect.
