Polarization conversion using hybrid near-zero and high-index metamaterials

TL;DR

This paper introduces a novel polarization conversion method using hybrid near-zero and high-index metamaterials, enabling efficient linear-to-circular polarization transformation in reflection and transmission, with potential applications across terahertz to optical frequencies.

Contribution

It presents a new device design leveraging near-zero index effects for polarization conversion, expanding the functional capabilities of metamaterials in optical applications.

Findings

Polarization conversion achieved in both reflection and transmission.

Loss impacts the performance of the polarization conversion.

Designs are feasible with naturally available epsilon-near-zero materials.

Abstract

Near-zero-refractive index materials display unique optical properties such as perfect transmission through distorted waveguides, cloaking, and inhibited diffraction. Compared to conventional media, they can fundamentally behave differently to light impinging from air, owing to the phenomenon of total external reflection. This makes them attractive for evanescent wave phenomena without prism coupling or sub-wavelength air gaps. Here, we introduce a strategy for linear-to-circular polarization conversion based on this effect. Practically realizable device designs are presented using hybrid structures of near-zero index and high index materials in a simple planar geometry. Our results predict polarization conversion in both reflection and transmission configurations based on naturally available epsilon-near-zero materials and illustrate the role of loss in limiting performance. Although the operation wavelength is limited to the epsilon-near-zero region, the concept can be implemented from the terahertz to optical domains using tunable epsilon-near-zero materials.