Polarization properties of a periodically-modulated metal film in regions of anomalous optical transparency

We present an analytical treatment of the resonance optical effects in which an arbitrarily polarized wave is incident at an arbitrary angle onto a periodically-modulated metal film in the conical mount. We show that under enhanced light transmittance conditions, not only intensity, but also the polarization of both reflected and transmitted waves undergoes significant changes. An in-depth investigation of the polarization transformation including the polarization conversion for both zeroth and nonzeroth diffraction orders is carried out. Besides, we derive novel polarization reciprocity relations.