ABSTRACT
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 â¼0.97 (â¼0.99) at frequency 144.18 THz (150.86 THz).
ABSTRACT
In this work, we design a structure of metamaterials that consists of double sliver-ring resonators, in which highly-dispersive unidirectional reflectionlessness and absorption are achieved based on high-order plasmon resonance. Reflections of +z and -z directions at 461.34 THz (456.68 THz) are â¼0 (0.82) and â¼0.85 (0) when the distance d=222.9 nm (259.8 nm), respectively. High absorption of â¼0.97 and the quality factor of â¼435 can be obtained in the loss metal structure at room temperature. What's more, unidirectional reflectionlessness is investigated at low temperature.
ABSTRACT
Dual-band unidirectional reflectionlessness at exceptional points is investigated theoretically in a non-Hermitian plasmonic waveguide system, based on near-field coupling by using only two resonators. The system consists of a metal-insulator-metal waveguide end-coupled to two nanohole resonators. The reflectivity for the forward (backward) direction is â¼0 (â¼0) at frequency 205.20 THz (194.56 THz), while for the backward (forward) direction it is â¼0.76 (â¼0.78). Moreover, the quality factors of the dual-band unidirectional reflectionlessness for forward and backward directions can reach â¼132 and â¼137, respectively.
ABSTRACT
Dual-band unidirectional reflectionless propagation at two exceptional points is investigated in metamaterial, which is composed of only two gold resonators with circular holes, by simply manipulating the angle of incident wave and distance between two resonators. Furthermore, the dual-band unidirectional reflectionless propagation can be realized in the wide ranges of incident angle from 0 ∘ to 50 ∘ and distance from 255 nm to 355 nm between two resonators. In addition, our scheme is insensitive to polarization of incident wave due to the circular-hole structure of the resonators.
ABSTRACT
Unidirectional reflectionless phenomena are investigated theoretically in a non-Hermitian quantum system composed of several quantum dots and a plasmonic waveguide. By adjusting the phase shifts between quantum dots, single- and dual-band unidirectional reflectionlessnesses are realized at exceptional points based on two and three quantum dots coupled to a plasmonic waveguide, respectively. In addition, single- and dual-band unidirectional perfect absorptions with high quality factors are obtained at the vicinity of exceptional points.
ABSTRACT
Dual-band unidirectional reflectionlessness and coherent perfect absorption (CPA) are demonstrated in a non-Hermitian plasmonic waveguide system based on near-field coupling between a single resonator and the resonant modes of two resonators showing an electromagnetically induced-transparency-like (EIT-like) effect. The non-Hermitian plasmonic system consists of three metal-insulator-metal (MIM) resonators coupled to a MIM plasmonic waveguide.
ABSTRACT
An effective scheme on switching the exceptional point(EP) where unidirectional reflectionlessness occurs is firstly proposed in non-ideal PT metamaterial via the polarization of incident light. The unidirectional reflectionlessness could be effectively controlled only by adjusting the phase coupling of the two resonators which are consisted of two identical but vertically placed crosses and are excited by incident light as an effective gain. Besides, the unidirectional perfect absorber occurs in the vicinity of EP.
ABSTRACT
We propose a scheme to achieve a controllable unidirectional reflectionless propagation at exceptional point (EP) in a non-ideal parity-time metasurface consisting of two silver ring resonators. The unidirectional reflectionless propagation can be manipulated by simply adjusting the angle of incident wave and the distance s between two silver rings based on the far field coupling. In addition, the angle of incident wave in a wide range of â¼25° is available to achieve the unidirectional reflectionless propagation. Moreover, the unidirectional reflectionless propagation at EP is insensitive to the polarization of incident wave due to the two-ring structure.
ABSTRACT
We investigate the quantum entanglement between two quantum dots (QDs) in a plasmonic waveguide with a near-zero mode index, considering the dependence of concurrence on interdot distance, QD waveguide frequency detuning, and coupling strength ratio. High concurrence is achieved for a wide range of interdot distances due to the near-zero mode index, which largely relaxes the strict requirement of interdot distance in conventional dielectric waveguides or metal nanowires. The proposed QD waveguide system with near-zero phase variation along the waveguide near the mode cutoff frequency shows very promising potential in quantum optics and quantum information processing.
ABSTRACT
We demonstrate a quantum phase flip gate between two QDs that resonantly couple to plasmonic double-bar resonators with asymmetric coupling strengths. Large coupling strengths can be achieved due to the deep subwavelength mode volumes of the optical modes in plasmonic double-bar resonators. High fidelity (~98%) and high success probability of the phase gate operation have been obtained when the coupling strength ratio (g2/g1) and resonant mode decay rate (κ/g1) are optimized. The subwavelength-scale plasmonic structures provide tremendous potential for solid-state quantum information processing.
ABSTRACT
Using a planar metamaterial, which consists of two silver strips, we theoretically demonstrate the plasmonic electromagnetically-induced transparency (EIT)-like spectral response at optical frequencies. The two silver strips serve as the bright modes, and are excited strongly by the incident wave. Based on the weak hybridization between the two bright modes, a highly-dispersive plasmonic EIT-like spectral response appears in our scheme. Moreover, the group index is higher than that of another scheme which utilizes the strong coupling between the bright and dark modes.