Enhanced backscattering of electromagnetic waves from randomly rough gratings on negative magnetic metamaterials

We investigate the scattering formalism of the Green's theorem including a discontinuity in the magnetic permeability μ (isotropic and homogeneous). For this purpose we make use of the continuity or saltus conditions for the EM field across the interface between media having different ɛ and μ. Numerical analysis has been made for linearly polarized light and randomly rough media with negative μ on the phenomenon of backscattering enhancement. We obtain enhanced backscattering peaks for both polarizations (s and p) in the case of rough surfaces with large correlation length. On the other hand, in the case of subwavelength roughness, enhanced backscattering is also observed, but mediated by s-polarized surface-plasmon polaritons (negative μ) similar to that mediated by p-polarized surface-plasmon polaritons for conventional metallic media (negative ɛ).