高斯波束在异向介质棱镜中的折射

为了验证异向介质的左手特性,分别采用棱镜实验和时域有限差分法(FDTD)模拟的方法对高斯波束透过异向介质棱镜的传播特性进行研究.异向介质采用周期排列的金属棒和金属环谐振器(SRR)结构,棱镜实验放在平板波导中测量.异向介质中的金属棒与平板波导上下电壁保持电连续,从而产生很好的电等离子效应.在数值模拟中采用高斯波束代替平面波研究能更好的符合实验中的入射波条件.实验和模拟研究结果都显示,折射波束与入射波束位于法线的同一侧,从而表明高斯波束在异向介质/空气交界面处发生了负折射,并且通过测量折射角求出了异向介质的等效折射率.

Refraction of Gaussian beam in prism of metamaterials

In order to verify the left-handed property of a metamaterial, the transmission property of a Gaussian beam through a prism of such material was studied by an experimental and a numerical finite difference time domain (FDTD) methods. The metamaterial sample was realized by using a periodic arrangement of wires and split-ring resonators(SRR). The beam refraction experiment was measured in a parallel waveguide. The wires maintain electrical continuity with the bounding metal surface of the waveguide plates, and exhibited a clear electrical plasma behavior. To reasonably simulate the incident wave, a Gaussian beam instead of a plane wave was used in the numerical model. Both the experimental result and the numerical simulation show that 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 metamaterial and air. The effective refractive index of the material was obtained by measuring the refractive angle of the outputted beam.