| Metal-dielectric thin film multilayers are of significant interest as transparent conductors, band-pass filters, and metamaterials. This thesis describes an experimental study of optical tunnelling through periodic metal-dielectric (MD) multilayers with the goal of optimizing the transmittance for either propagating or evanescent waves. Surface-plasmon mediated tunnelling was studied in structures with a symmetric SiO2-Ag-SiO2 unit cell. Tunneling of TE-polarized propagating waves was studied in structures with a symmetric TiO2-Ag-TiO2 unit cell. In both cases, reasonable agreement between experimental results and theoretical predictions was obtained, indicating that potential transmittance theory and admittance-matching concepts can be used to optimize the transmittance of such structures. However, more predictable and stable results were obtained for the SiO2-based structures compared to the TiO2-based structures, which was attributed to oxidation of the Ag layers in the latter case. This motivated a study on alternative termination strategies to improve the peak transmittance of Ag/SiO 2-based multilayers. |
