In this paper, four optical filter topologies based on metal–insulator–metal waveguides are proposed and the designed structures are investigated numerically using finite-difference time-domain method. Triangular-shaped adjunctions have been added to the filter structures to improve their transmission spectrum. These improved structures consist of air as the insulator and silver as the metal. The relative permittivity of metal has been described via the Drude, Drude–Lorentz, and Palik models. The first filter’s transmission spectrum shows an acceptable transmittance. In the second optimized filter, the transmission spectrum has been improved. The transmittance spectrum can be tuned through adjusting the edge of the triangle in these four optimized filters. As a result, the bandwidths of resonance spectra can be adjusted. The theory of such tapered structures will be investigated by the tapered transmission line and will be solved with the transfer matrix method. This method show...

中文翻译：

---

用于改进技术参数的具有不同几何形状的MIM等离子体激元滤波器的分析，设计和仿真

本文提出了四种基于金属-绝缘体-金属波导的滤光器拓扑结构，并使用时域有限差分法对设计的结构进行了数值研究。三角形附加物已添加到滤波器结构中，以改善其透射光谱。这些改进的结构由作为绝缘体的空气和作为金属的银组成。金属的相对介电常数已通过Drude，Drude-Lorentz和Palik模型进行了描述。第一滤波器的透射光谱显示出可接受的透射率。在第二优化滤波器中，透射光谱得到了改善。可以通过调整这四个优化滤镜中三角形的边缘来调整透射光谱。结果，可以调节共振谱的带宽。这种锥形结构的理论将通过锥形传输线进行研究，并将通过传递矩阵法解决。此方法显示...