An Ultra-Wideband Bandstop Plasmonic Filter in Mid-Infrared Band Based on Metal-Insulator-Metal Waveguide Coupled with an Hexagonal Resonator

Abstract An ultra-wideband bandstop plasmonic filter (UWB- BSF) in Mid-Infrared (MIR) band based on Metal-Insulator-Metal (MIM) waveguide coupled with an hexagonal resonator is proposed in this work. The designed BSF is investigated numerically and theoretically using the FDTD method. To improve the performance of the proposed nano-filter by broadening the stopband wavelength we increased the number of hexagonal resonators. Fano resonance appears with the addition of the second hexagonal resonator, it can be adjusted by tuning the separation distance S between the centers of two cavities. In addition, the filtering ranges and the center wavelength can be revised and shifted to longer wavelengths by varying the geometric parameters of hexagonal resonators. This nanostructure provides an advantageous application for plasmonic integrated circuits and broadband transmissions.