Broadband Epsilon-Near-Zero Metamaterials with Step-Like Metal-Dielectric Multilayer Structures

TL;DR

This paper introduces broadband epsilon-near-zero metamaterials using step-like metal-dielectric multilayer structures, enabling novel optical functionalities like directional emission and phase shaping across a wide frequency spectrum.

Contribution

It proposes a new design of broadband ENZ meta-atoms based on layered stacks with specific metallic ratios, advancing optical metamaterials technology.

Findings

Successful design of broadband ENZ meta-atoms in optical frequencies

Demonstration of broadband directional emission

Realization of phase front shaping

Abstract

The concept of the broadband epsilon-near-zero meta-atom consisting of layered stacks with specified metallic filling ratio and thickness is proposed based on the Bergman spectral representation of the effective permittivity. The step-like metal-dielectric multilayer structures are designed to achieve realistic broadband epsilon-near-zero meta-atoms in optical frequency range. These meta-atoms can be integrated as building blocks for unconventional optical components with exotic electromagnetic properties over a wide frequency range, such as the demonstrated broadband directional emission and phase front shaping.