Robust Extraction of Hyperbolic Metamaterial Permittivity using Total Internal Reflection Ellipsometry
Cheng Zhang, Nina Hong, Chengang Ji, Wenqi Zhu, Xi Chen, Amit K. Agrawal, Zhong Zhang, Tom E. Tiwald, Stefan Schoeche, James N. Hilfiker, L. Jay Guo, Henri J. Lezec
Hyperbolic metamaterials are optical materials characterized by highly anisotropic effective permittivity tensor components having opposite signs along orthogonal directions. The techniques currently employed for characterizing the optical properties of hyperbolic metamaterials are limited in their capability for robust extraction of the complex permittivity tensor. Here we demonstrate how an ellipsometry technique based on total internal reflection can be leveraged to extract the permittivity of hyperbolic metamaterials with improved robustness and accuracy. By enhancing the interaction of light with the metamaterial stacks, improved ellipsometric sensitivity for subsequent permittivity extraction is obtained. The technique does not require any modification of the hyperbolic metamaterial sample or sophisticated ellipsometry set-up, and could therefore serve as a reliable and easy-to-adopt technique for characterization of a broad class of anisotropic metamaterials.