Nonlocal Optical Response of Plasmonic Nanowire Metamaterials.

摘要

Nanowire metamaterials are a class of composite photonic media formed by an array of aligned plasmonic nanowires embedded in a dielectric matrix. Depending on exact composition, geometry, and excitation wavelength, nanowire structures are known to exhibit elliptical, hyperbolic, or epsilon-near-zero (ENZ) responses. In the ENZ regime, optical response of the composite becomes strongly nonlocal. Excitation of an additional wave, caused by nonlocality, has been experimentally demonstrated in nanowire-based metamaterials. In this thesis, a computational study of the nonlocal optical response in plasmonic nanowire arrays has been conducted to better understand such materials. The results of this computational study were used to develop an analytical technique that provides an adequate description of the optical response of wire based metamaterials. This formalism combines the local and nonlocal effective-medium theories often used to describe the optics of nanowire composites. It provides insight into the origin of the additional wave and allows implementation of additional boundary conditions. This approach can be straightforwardly extended to describe the optics for numerious plasmonic structures.