Magnetic hyperbolic optical metamaterials

TL;DR

This paper demonstrates magnetic hyperbolic dispersion in 3D metamaterials, enabling dual electric and magnetic responses, which enhances thermal emission control and offers new opportunities for impedance-matched optical devices.

Contribution

The first experimental realization of magnetic hyperbolic dispersion in three-dimensional metamaterials, revealing topological phase transitions and enhanced thermal emission.

Findings

Observation of topological phase transition between elliptic and hyperbolic dispersion

Strong directional, coherent, and polarized thermal emission in hyperbolic regime

Potential for impedance-matched hyperbolic media for unpolarized light

Abstract

Strongly anisotropic media where the principal components of electric permittivity or magnetic permeability tensors have opposite signs are termed as hyperbolic media. Such media support propagating electromagnetic waves with extremely large wavevectors exhibiting unique optical properties. However in all artificial and natural optical materials studied to date, the hyperbolic dispersion originates solely from the electric response. This restricts material functionality to one polarization of light and inhibits free-space impedance matching. Such restrictions can be overcome in media having components of opposite signs for both electric and magnetic tensors. Here we present the experimental demonstration of the magnetic hyperbolic dispersion in three-dimensional metamaterials. We measure metamaterial isofrequecy contours and reveal the topological phase transition between the elliptic and hyperbolic dispersion. In the hyperbolic regime, we demonstrate the strong enhancement of thermal emission, which becomes directional, coherent and polarized. Our findings show the possibilities for realizing efficient impedance-matched hyperbolic media for unpolarized light.