Strong Purcell effect in anisotropic $\varepsilon$-near-zero metamaterials

TL;DR

This paper theoretically demonstrates a strong Purcell effect in anisotropic epsilon-near-zero metamaterials, leading to enhanced radiative decay and emission without relying on diverging density of states, unlike hyperbolic metamaterials.

Contribution

It introduces a new mechanism for Purcell enhancement in epsilon-near-zero anisotropic metamaterials that does not depend on hyperbolic dispersion or evanescent waves.

Findings

Enhanced radiative decay rate in anisotropic epsilon-near-zero metamaterials

Far-field emission power is increased in these structures

The effect is realizable in layered metal-dielectric nanostructures

Abstract

We theoretically demonstrate the strong Purcell effect in $\varepsilon$-near-zero ultra-anisotropic uniaxial metamaterials with elliptic isofrequency surface. Contrary to the hyperbolic metamaterials, the effect does not rely on the diverging density of states and evanescent waves. As a result, both the radiative decay rate and the far-field emission power are enhanced. The effect can be realized in the periodic layered metal-dielectric nanostructures with complex unit cell containing two different metallic layers.