Light propagation in multilayer metamaterials

Metamaterials are artificially constructed materials composed of sub-wavelength building blocks that are designed to interact with light in ways that cannot be achieved with natural materials. Over the last years, improvements in nanoscale fabrication and in metamaterial design have led to the development of metamaterials based on resonant nanostructures for the microwave and infrared spectral range. Material absorption limits the realization of resonant metamaterials in the visible spectral range. Furthermore, increasing fabrication complexity limits the assembly of three-dimensional resonant metamaterials in the visible and UV spectral range, as the typical feature size smaller than the wavelength is reduced.
This thesis presents a three-dimensional metamaterial design composed of a metal-dielectric thin-film multilayer stack. Light propagation in the optical metamaterial can be controlled by the layer geometry. The multilayer design benefits from the numerous fabrication techniques which are readily available to realize multilayer structures. Furthermore, because light is coupled to guided waves in the metamaterial, rather than confined to a localized resonance, absorption losses are reduced. Because of these advantages, the realization of a three-dimensional metamaterial operating in the visible and UV spectral range becomes possible. We demonstrate optical properties that do not exist in natural materials, such as a vanishing permittivity at a specific wavelength of choice, negative refraction of energy leading to a flat lens, and a structure with 100% coupling efficiency while not index matched to its surroundings.