Polarization enhanced optical transmission through plasmonic metal films with high aspect ratio apertures

摘要

The effects of period, geometry, and thickness on optically thick metal films perforated with subwavelength apertures have been an area of recent investigation, both experimentally and theoretically. It has been shown that the spectra of these films can be scaled proportionally to the period. Different geometries can change peak positions, and the thickness of a metal film can determine the degree of transmission for the entire spectrum. This tunability allows the positioning of a single peak to a wavelength of interest, but the position of all other peaks are dependent on the peak of interest and cannot be positioned independently. Further, the peak intensities are all related. This lack of individual control over specific peaks limits the future applicability of plasmonic films in optoelectronic and photonic devices. Transmission spectra that can be tuned by the polarization of the incident light can be fabricated with novel array structures. Further, control over the transmission spectra can be gained by using highly anisotropic apertures to modifying specific surface plasmon polariton modes and their associated peaks. Surface plasmon polariton modes that are not in the direct path of these anisotropic apertures are not significantly affected. This allows for controlled engineering of the intensity of peaks within the visible, greatly increasing the tailorability of the spectral characteristics of plasmonic films.