Dual-band unidirectional reflectionless phenomenon based on high-order plasmon resonators in plasmonic waveguide system

We investigate the dual-band unidirectional reflectionless phenomenon and near perfect absorption using high-order plasmon resonators at exceptional points based on near-field coupling in plasmonic waveguide system. The system consists of two high-order plasmon resonators end-coupled to a metal-insulator-metal plasmonic waveguide. The reflection for forward (backward) direction is close to 0.85 (0.74), while for backward (forward) direction is approximate to 0 (0) at a frequency of 199.8 THz (206.1 THz), and the quality factor of absorption spectrum is about 257.6 (217.2) at 206.1 THz (199.8 THz) for forward (backward) direction.