高斯波束在双负媒质中的传播特性分析

Characteristics of Gaussian beam propagation through double negative media slab

提出了一种基于Drude色散媒质模型的2维TM模时域有限差分法,数值模拟了高斯波束从自由空间垂直入射和斜入射到双负媒质(介电常数和磁导率同时为负)平板后的折射现象,并给出了平板内外的电场强度分布。模拟结果显示:垂直入射时,双负媒质平板对高斯波束具有汇聚作用,通过改变媒质的折射率,可以控制高斯波束通过组合平板的传播时间而不发生衰减;斜入射时,折射波束与入射波束均位于法线的同一侧,高斯波束在双负媒质与空气交界面处发生了负折射。

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.