Characteristics of Gaussian beam propagation through double negative media slab

An improved 2D finite difference time domain (FDTD) method for TM mode based on the lossy Drude dispersive models is presented. The characteristics of a Gaussian beam propagation through a double negative media(DNG) slab are studied by using the dispersive FDTD method. Meanwhile, the electric field intensity distributions inside and outside the DNG slab are presented. The results show that the DNG slab can focus the normal incident Gaussian beam, and that as to the oblique incident one, the refracted beam and the incident beam are on the same side of the normal, which suggests that the Gaussian beam undergoes a negative refraction in the interface of DNG slab and air. The results validate the dispersive FDTD method in this paper.