Design and Optimization of Epsilon-Near-Zero Metamaterial for Negative Refraction

Negative refraction is a nonlinear optical phenomenon in which light crosses the interface between two materials and is refracted at an angle negative relative to the normal line. Negative refraction shows great promise in applications to high depth-of-field endoscopes in oncology, as well as super lensing and ultra-fast signal processing. Negative refraction typically requires high intensity incident light to be witnessed, but through the joint phenomena of epsilon-near-zero (ENZ) modes and localized surface plasmon polaritons (LSPP), negative refraction can be achieved at orders of magnitude lower intensity incident light. In this work, we computationally optimized four materials exhibiting ENZ modes in the visible and near-infrared using a combination of three metals with strong LSPP responses and six novel nanophotonic structures in Ansys Lumerical's FDTD. We find that strongly coupled metamaterials exhibit surface energy density enhancement in excess of 300x, revealing optimal metamaterial combinations as strong candidates for producing efficient negative refraction at the on-chip scale.