Longitudinal elliptically polarized electromagnetic waves in off-diagonal magnetoelectric split-ring composites

J Phys Condens Matter. 2009 Jul 22;21(29):292202. doi: 10.1088/0953-8984/21/29/292202. Epub 2009 Jun 19.

Abstract

We study the propagation of plane electromagnetic waves through different systems consisting of arrays of split rings of different orientations. Many extraordinary EM phenomena were discovered in such systems, contributed by the off-diagonal magnetoelectric susceptibilities. We find a mode such that the electric field becomes elliptically polarized with a component in the longitudinal direction (i.e. parallel to the wavevector). Even though the group velocity [Formula: see text] and the wavevector k are parallel, in the presence of damping, the Poynting vector does not just get 'broadened', but can possess a component perpendicular to the wavevector. The speed of light can be real even when the product ϵμ is negative. Other novel properties are explored.