Liquid Crystal-Based Dielectric-Loaded Plasmonic Ring Resonator Filter

A new tunable plasmonic filter based on liquid crystal dielectric loaded plasmonic waveguide is proposed and studied. The transmission spectrum can be controlled easily by applying a constant external electric field to the plasmonic filter. The physical principle of this phenomenon is evaluated from the phase of surface plasmon polaritons (SPPs) in the waveguide and the electro-optical effect of liquid crystals. Our numerical simulations with finite-difference time-domain (FDTD) technique reveal that a large tuning range of the transmission spectrum can be achieved. Both the electrical switching and optical properties of the proposed structure are investigated in the context of designing an optical switch. The special feature of the proposed structure gives it an opportunity to be used as an efficient element in ultrahigh nano-scale integrated photonic circuits for miniaturization and tuning purposes.