Super Scatterers Based on Artificial Localized Magnon Resonances

TL;DR

This paper introduces artificial magnon resonances in metamaterials to create super scatterers with extremely high electromagnetic scattering, surpassing natural materials and enabling advanced applications in communications and radar systems.

Contribution

It demonstrates the design of subwavelength metamaterial spheres with negative permeability that achieve giant scattering cross sections through artificial magnon resonances.

Findings

High scattering cross section exceeds natural steel spheres by four orders of magnitude.

Metamaterial-based scatterers have scattering comparable to large aircraft in low-frequency radar.

Artificial resonances enable tunable and highly efficient electromagnetic scatterers.

Abstract

The interaction between electromagnetic waves and objects is strongly affected by the shape and material composition of the latter. Artificially created materials, formed by a subwavelength structuring of their unit cells, namely metamaterials, can exhibit peculiar responses to electromagnetic radiation and provide additional powerful degrees of freedom to the scatterer design. In particular, negative material susceptibilities give rise to strong resonant interactions with deeply subwavelength particles. While the negative electrical permittivity of natural noble metals manifests itself in localized plasmon resonant oscillations, negative magnetic permeability is virtually non-existent in nature. Here the concept of artificial magnon resonance in subwavelength objects with effective negative permeability, designed based on the metamaterial approach, is demonstrated. Strong localized oscillations of the magnetic fields within an array of split ring resonators, forming a sphere, hybridize in a collective mode of the structure. As a result, extremely high scattering cross section, exceeding that of a steel sphere with the same radius by four orders of magnitude, was demonstrated. Furthermore, the scattering cross section of subwavelength metamaterial-based sphere was shown to be comparable to the low frequency (MHz) radar signature of a big military aircraft. Super scatterers, based on tunable resonances within artificially created materials, can find use in a broad range of electromagnetic applications, including wireless communications, radars, RFID, internet of things hardware and many others.