Design and Characterization of Optical Metamaterials Using Tunable Polarimetric Scatterometry.

摘要

Optical metamaterials are a class of engineered materials with a wide range of material properties and an equally wide range of anticipated applications. This research targets optical metamaterials in two ways. First, the dimensional constraints necessary to bring effective medium theory (EMT) into agreement with the already well-established transfer matrix method (TMM) modeling for a periodic, stratified (metal-dielectric) near-zero permittivity structure were determined. This provided a path to leverage the use of EMT in the design of near-zero permittivity structures and accurately predict its post- fabrication behavior. Second, the first tunable infrared (IR) Mueller matrix polarimeter-scatterometer was developed to capture the full-directional, full- polarimetric behavior of IR metamaterials. Modeling was used to determine the optimal dual rotating retarder configuration to apply to the instrument design, which was subsequently implemented. Free-space measurements corroborated the optimized design with Mueller matrix extractions having less than 1% error. The instrument was then used to measure a unique metamaterial absorber at 5 microns and captured the polarimetric behavior of a surface plasmon polariton resonance as a function of incident angle. Modeling was used to distill the s-polarized and p-polarized reflectance behavior and phase differences in the reflectances that led to the resonant signature in the measured results. As a final step, the measured results were used to predict the reflectance behavior of the material against a series of incident canonical polarization states.