It has been demonstrated that the reflected beam displays either a forward or a backward beam shift. An approximate analytical solution has shown that the initial Gaussian beam profile splits into two. The theory of leaky waves has also been applied to acoustic beams incident on a liquid-solid interface, with the aim of presenting a unified theory of the beam shifting effect near the Rayleigh angle [@Bertoni]. The GH effect of a light beam incident on a dielectric slab from the air has been studied with an emphasis on the transmitted beam [@Li]. Lakhtakia has pointed out that the GH shift reverses its direction when $\epsilon < 0$ and $\mu < 0$ in the optically rarer medium [@Lakhtakia]. The enhancement of the GH shift and the control of the reflected field profile has been achieved by adding a defect or cladding layer to photonic crystals [@He; @Wang]. Recently, De Leo [*et al.*]{} have performed an extended study investigating the asymmetric GH effect and derived an expression for the GH shift valid in the region where the Artmann formula diverges [@Leo1; @Leo2; @Leo3; @Leo4].

Light waves confined to the surface of a medium and surface charges oscillating resonantly with the light 