Polarization properties of the enhanced light transmission through a thin gold film perforated with an array of subwavelength elliptical holes have been studied. It is shown that broadband optical transmission can be achieved through such nanostructures due to the complex nature of the SPP Bloch modes related to a periodic lattice with a low symmetry primitive cell. The optical transmission is dependent on both the incident and transmitted light polarization states even at normal incidence. Using this feature it is therefore possible to tune the transmission spectrum by selecting the polarization of the incident and/or transmitted light. It is shown that such a nanostructure acts as a thin two-dimensional birefringent crystal with wavelength dependent principal optical axes: the property which is not encountered in natural crystals. A rotation of the polarization of the light transmitted through an array of subwavelength holes strongly depends on the thin layer of chiral material placed upon the nanostructured surface. The polarization rotation effect of the chiral molecules appeared to be coupled with the polarization properties of the metallic structure related to SPP excitations. Optical components based on nanostructured metallic systems can find numerous photonic applications space-based and terrestrial systems in extreme ambient conditions.
High-resolution optical techniques for the imaging of magnetic domains in ferromagnetic materials such as confocal microscopy and scanning near-field optical microscopy are discussed. The imaging capabilities of different techniques and image formation are investigated in the case of in-plane as well as out-of-plane magnetic anisotropy in different polarisation configurations. It is shown that the magneto-optical resolution of near-field measurements depends on the film thickness and is limited by the diffraction on magnetic domains throughout the film. For thin magnetic films, sub-wavelength resolution can be achieved. High-resolution optical imaging is required for characterisation of the micro-magnetic and magneto-optical properties of novel magnetic materials in order to adopt a bottom-up approach in the search for new materials with improved characteristics.