| Significant research has been performed in recent years on the enhanced transmission of light in metal films containing periodic arrays of subwavelength holes. Standard aperture theory does not account for the noted enhancement which can be up to three orders of magnitude larger than predicted. A surface plasmon polariton (SPP) resonance accounts for the increased transmission as is well documented in the literature. The extraordinarily transparent (EOT) film has a transmission spectrum that is composed of peaks corresponding to different SPP modes. It has been found that through various techniques, the spectral position of these peaks can be controlled with great precision.; Beginning with simple variations of structure, the spectrum is tuned. Methods include the formations of anisotropic arrays to break the degeneracy in the x and y directions, corresponding to the [1,0] and [0,1] SPP modes, respectively. To these structures, additional apertures can be added as a sublattice of sorts. Through these novel two dimensional crystal structures, individual SPP modes can be interrupted.; The material properties of the metal films also contribute greatly. To that end, the use of composite metal films has been studied. The metals were varied within a skin depth to yield an effective dielectric constant that is a weighted average of the materials. Results show that peak position can be fined tuned with spectral shifts of just a few nanometers to over 50 nm. More so, the band diagram can be engineered with metal layering.; The future use of plasmonic films is not limited to passive components only, but active components can also be constructed. When such control is obtained, the possibilities for the use of plasmonic films as modulators, pixels, and filters can also be envisioned. By making use of aperture geometry, we demonstrate control over the emission spectra with the polarization of the incident light. This is not limited to only a simple on/off technology, but color-switching arrays have also been fabricated. Devices that can modulate light by means of mechanical actuators have been modeled and the design of a nonlinear plasmonic film has been suggested. |
