Giant Asymmetric Radiation from an Ultrathin Bianisotropic Metamaterial

TL;DR

This paper demonstrates that ultrathin bianisotropic metamaterials can produce highly asymmetric unidirectional radiation, significantly advancing control over electromagnetic emission without breaking reciprocity.

Contribution

It introduces a novel approach using magnetic plasmons in ultrathin metamaterials to achieve unprecedented radiation asymmetry.

Findings

Achieved a forward-to-backward emission asymmetry of 1:32

Demonstrated that thin metamaterials (~λ0/8) can produce high asymmetry

Showed potential for applications in directional emitters and lasers

Abstract

Unidirectional radiation is of particular interest in high-power lasing and optics. Commonly, however, it is difficult to achieve a unidirectional profile in such a system without breaking reciprocity. Recently, assisted by metamaterials without structural symmetry, antennas that radiate asymmetrically have been developed, hence providing the possibility of achieving unidirectionality. Nevertheless, it has been challenging to achieve extremely high radiation asymmetry in such antennas. Here, we demonstrate that this radiation asymmetry is further enhanced when magnetic plasmons are present in the metamaterials. Experimentally, we show that a thin metamaterial with a thickness of approximately {\lambda}_0/8 can exhibit a forward-to-backward emission asymmetry of up to 1:32 without any optimization. Our work paves the way for manipulating asymmetric radiation by means of metamaterials and may have a variety of promising applications, such as directional optical and quantum emitters, lasers, and absorbers.