Optical-magnetism-induced transparency in a metamaterial

In this paper, we theoretically demonstrate that electromagnetic transparency can be induced by optical magnetism in a metamaterial, which is composed of metamolecules. Each metamolecule consists of a metallic split-ring resonator, as one bright meta-atom (which is optically magnetic), and also a cut-wire pair, as one dark meta-atom (which is optically nonmagnetic). It is found that magnetic resonances occur at optical frequencies due to the local magnetic interaction between “bright” meta-atoms and “dark” meta-atoms; thereafter, a transparency window emerges upon the original absorption background. The phenomenon is similar to the electromagnetically induced transparency (EIT) in atomic three-level systems, and a microscopic picture is given to compare it with the EIT. Furthermore, low loss and slow light in this metamaterial have also been verified. The investigations may achieve potential applications on integrated optical circuits.