  Using simulations and theoretical arguments we investigate the specular
reflection of a perforated gold film deposited on a glass substrate. A square
lattice of cylindrical holes is assumed to produce the periodic lateral
corrugation needed to hybridize the surface plasmons with radiative states. It
is shown that, contrasting transmission approaches, a knowledge of the
reflection on either side of the film provides separate information on the
gold-vacuum surface plasmons and on the gold-glass interface plasmons. Recent
experimental data on a specific implementation of this system are reexamined;
these show a good agreement between the measured reflections and the
simulations in both directions of incident wave probes. This confirms the
importance of taking into account the reflection asymmetry in the far-field
assessment of surface plasmons properties.
