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We theoretically investigate an controlled unidirectional reflectionlessness and near perfect absorption by applying external voltage in an electro-optical plasmonic waveguide system based on near-field coupling between two resonators. The system consists of two resonators side coupled to a metal-dielectric-metal plasmonic waveguide. Based on the numerical simulation, when external voltage is U = 7.4 V, the reflections for forward and backward directions are close to 0 and 0.82 at frequency 144.18 THz, while the reflections for forward and backward directions are close to 0.81 and 0 at frequency 150.86 THz when external voltage is U = 1.5 V. And the high absorption for forward (backward) direction is ∼0.97 (∼0.99) at frequency 144.18 THz (150.86 THz).

We demonstrate the possibility of dual-band unidirectional reflectionlessness in a non-Hermitian quantum system composed of a plasmonic waveguide and two end-coupled plasmonic cavities (PCs). Our scheme exhibits dual-band unidirectional reflectionlessness can be obtained at exceptional points by properly adjusting the coupling strength between two PCs, the ratio of decay rates of two PCs, and the ratio of plasmonic cavity-waveguide coupling strengths. As a valuable feature, the quality factor reaches to ∼175.4 in forward direction, while the backward quality factor is close to ∼188.2.

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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[Formula: see text]THz (206.1[Formula: see text]THz), and the quality factor of absorption spectrum is about 257.6 (217.2) at 206.1[Formula: see text]THz (199.8[Formula: see text]THz) for forward (backward) direction.