基于金属-电介质-金属结构, 提出了一种带有支节的表面等离子体T型分束器, 采用有限时域差分法研究其透射率与结构参量之间的关系.计算结果表明: 改变T型波导中支节的宽度和长度, 输出波导表面等离子体功率周期性变化; 改变支节在T型波导支路中的纵向位置, 金属-电介质-金属波导中表面等离子体分束比周期性变化; 当分束比达到最大(或最小)时, T型分束器实现表面等离子体的定向传播.此外, 采用表面等离子体干涉理论解释了分束比呈周期性变化的原因.

A T-shaped splitter of the surface plasmon waveguide with a stub based on metal-insulator-metal structure was proposed. The relationship between transmission and structure parameters was investigated by Finite-difference time-domain method. The simulation results show that the periodical changes of surface plasmons power can be achieved by changing the width and length of stub structure in T-shaped waveguide. Also, the periodical changes of splitting ratio for changes of surface plasmons can be obtained by changing the stub structure position of the output port in the metal-insulator-me waveguide structure. When the splitting ratio get maximum(or minimum), T-shaped splitter can achieve the unidirectional propagation of changes of surface plasmons. Besides, the periodical changes of splitting ratio was explained based on the changes of surface plasmons interference theory.