Band-pass and Band-stop Plasmonic Filters Based on Wilkinson Power Divider Structure

In this paper, plasmonic band-pass and band-stop filters employing ring resonators within the framework of the Wilkinson power divider structure are presented. It is shown that the resonance wavelengths can be effectively manipulated by adjusting the inner and outer radii of the ring resonators. Furthermore, by precisely controlling the gap size between the ring resonators and the waveguides, we have successfully designed efficient band-pass and band-stop filters. This study encompasses a thorough investigation into the propagating modes of surface plasmon polaritons (SPPs) within these filters. The transmission characteristics of the proposed filters are meticulously examined and analyzed using the finite-difference time-domain (FDTD) method. The proposed plasmonic filters exhibit a compact size, thus holding promising potential for integrated optics applications. Moreover, they possess the inherent capability to eliminate higher-order modes, enhancing their utility in practical implementations which require a single mode response. The proposed design has the possibility of manipulating the filtering wavelength by adjusting the stubs and ring parameters. This capability opens up exciting avenues for tuning the filter's response and tailoring it to the desired application requirements.