Spontaneous emission field excited by an atom near the μ-negative metamaterials slab

Abstract

This paper discusses the spontaneous emission field of a two-level atom near a μ-negative metamaterial(MNG) slab, in which the surface modes are excited. the μ-negative metamaterial is a kind of artificial-microstructured materials possessing effective negative permeability and positive permittivity. According to Maxwell's equations and boundary conditions, the MNG slab supports only TE-polarized surface modes.We analyze the properties of the surface mode, i.e.the number of the surface mode and its symmetry or antisymmetry profiles, supported by the MNG slab with different permeability and thickness, and then study the influence of these characteristics on the spatial distribution of the spontaneous emission field in detail. Results show that the distance between the atom and the slab can affect the ratio of surface mode to the total atomic emission field. When the surface mode plays the dominate role, the spontaneous emission field of the atom on the nearest surface of MNG slab are directionally propagating along y-axis if the atomic dipole is along x-axis due to the TE-polarized surface mode. The atomic emission field on the other surface depends on the symmetry of the surface modes and their percentage. If the symmetric and antisymmetric surface modes coexist, the field intensity on the right surface is weakened or even disappears completely, but if there exists only symmetric or antisymmetric surface mode, the field intensity on the right surface is nearly identical with that on the left surface. These phenomena are significantly different from the case of atoms near a metal slab or a dielectric slab. Our results are useful for the controllable atomic emission and have potential application to the single-photon source.