Tailor the surface-wave properties of a plasmonic metal by a metamaterial capping.

We show that putting an ultra-thin anisotropic metamaterial layer on a plasmonic surface significantly enriches the surface wave (SW) characteristics of the system, which now supports SWs with transverse-magnetic (TM) and transverse-electric (TE) polarizations simultaneously. In addition, the generated SWs exhibit hybridized polarization characteristics in certain cases, and a SW band gap opens within a particular propagation direction range. We designed and fabricated a realistic structure based on the proposed model, and combined microwave experiments with full-wave simulations to verify the fascinating theoretical predictions. Several potential applications of the proposed system are discussed in the end.