The optical response of metallic structures, commonly referred to as plasmonics, is currently a widely studied topic due to advances in experimental fabrication techniques and theoretical investigation. Having optical properties that depend on size and shape make these metals ideal candidates for sensor and device technology. The thesis presentation will outline the behavior of four plasmonic material systems, and uncover the underlying physics that governs their response to optical excitation. The anomalous optical properties of solution derived percolation films are verified using scaling theory. Characterization of amorphous nanolaminates leads to the creation of an effective medium with anisotropic hyperbolic dispersion which can be tuned with different ratios of constituent materials. The electrodynamics of vertically aligned multi-walled carbon nanotubes are derived through the development of a spectroscopic terahertz transmission ellipsometry algorithm. Lastly, a new diffraction based imaging system based on metallic gratings is presented to have resolution capabilities which far outperform the diffraction limit.