Negative-permeability electromagnetically induced transparent and magnetically active metamaterials

Metamaterials exhibiting negative electromagnetic parameters can enable a multitude of exciting applications, but currently their performance is limited by the occurrence of losses-particularly radiation losses, which dominate over their dissipative counterparts even in the optical regime. Here, a metamaterial configuration is conceived that judiciously generalizes the traditional electromagnetically induced transparency (EIT) scheme-by which radiation losses can be restrained-in such a way that EIT can be observed and exploited innegative-magnetic metamaterials. Analytic theory and three-dimensional simulations unveil the required route: introduction of poor-conductor meta-atoms next to the good-conductor meta-atoms of a magnetic metamaterial. This setup results in a frequency band where the metamaterial remains negative-magnetic, while its loss-performance dramatically improves owing to suppression of radiation damping. Furthermore, we show that placing the two meta-atoms on orthogonal planes gives rise to a passive anisotropic metamaterial exhibiting permeabilities with negative real parts (Re{mu}<0) and active imaginary parts (Im{mu}>0 for an e(+iwt) time dependence) along its principal crystallographic axes.