Optimization of Hyperbolic Metamaterials Using Gold, Silver, Copper, and Aluminum

Hyperbolic Metamaterials (HMMs) allow for the propagation of Surface Plasmon Polaritons (SPPs) and Long-Range Surface Plasmon Polaritons (LRSPPs), which interact to form what we call Bulk Plasmon Polaritons (BPPs). These HMM structures are promising in the field of refractive index sensing due to the unnaturally high effective refractive index of some modes propagating within the structures. Our goal is to achieve an effective refractive index of 8.1, which is approximately double the highest refractive index found in nature. These HMMs are made from nanolayers of alternating conducting and dielectric materials. We used silicon dioxide for our dielectric material in each of the following cases. Gold, silver, and copper achieved an effective refractive index of 8.1 or slightly greater with 26 7.5nm-thick layers and aluminum achieved this goal with 26 5.5nm-thick layers.