Low-MSE extraction of permittivity in optical hyperbolic metamaterials.

We describe the details of a procedure to obtain low mean-squared-error (MSE) values for the extraction of permittivity tensors of hyperbolic metamaterials (HMMs) using spectroscopic ellipsometry. We have verified our procedure through characterization of three different HMM samples having varying materials, periods, and fill factors. Our procedure eliminates the need for complicated ellipsometric measurements and modeling techniques, as well as the need for any additional optics such as prisms or index-matching gels. Therefore, a time-efficient and cost-effective approach is introduced, which is only dependent on software; hence, it can be easily and widely adopted. All the MSE values obtained in this Letter are below 1.00 while, at the same time, meaningful and reasonable permittivities are extracted from HMMs.