端面结构调控近红外波段金属光子晶体能量分束器

Near-infrared metallic photonic crystal power beam splitter based on surface modulation

为研究近红外波段光子晶体的光能量分束特性,通过对完整金属光子晶体平板的输入输出端面结构进行调制,实现在第4个方向带隙内的入射光分束特性。将入射端面上的金属银柱每隔1个去掉1个,使得频率位于方向带隙范围内的垂直入射光束能够有效进入光子晶体结构,并增加其在结构中的散射特性,进而通过改变在出射端面的金属银柱排列的周期性大小,实现对入射光的2分束、5分束、8分束和11分束特性。相对于通常的介质柱排列在空气中的光子晶体功率分束器和介质背景空气孔型光子晶体功率分束器,由金属嵌入介质背景中所组成的端面调控全固态光子晶体功率分束器结构稳定性高,不易受周围环境的变化而变化,并且不依赖入射光束的入射位置和入射宽度,在未来的全光集成回路中具有实际的应用前景。

The light beam splitting properties of the near -infrared two -dimensional photonic crystal (PhC) are theoretically studied using the finite -difference time -domain method, which are composed of a square -lattice of circular silver pillars arranged in the background of silicon dioxide and silicon, respectively. The light beam splitting characteristics through the above PhC structures within the fourth directional band gap are achieved by modulating the input and output surfaces of the metallic PhC. By removing one silver rod between two adjacent rods along the input surface, the normally -incident light beam within the directional band gap can be effectively transmitted into the PhC and the corresponding scattering characteristics is enhanced at the same time. The two -branch -channel, five -branch -channel, eight -branch -channel and eleven -branch -channel beam splitting behaviors are obtained by altering the periodical length of the circular silver column along the output surface. Compared with the traditional PhC power splitters consisted of dielectric rod arranged in the air background or air holes immersed in dielectric, the proposed structures are composed of metal rods embedded in dielectric background, it is full -solid and is not susceptible to the changes of the surrounding environment. This kind of beam splitter is not dependent on the incident position and incident width of the incident light beam, so that it has practical application prospect in the all -optical integrated circuit in the future.