Search

Two-dimensional plasmonic materials generally use patterned structural design to enhance the intensity of interaction with light near the resonance wavelength. We propose a non-patterned monolayer black phosphorus (BP) and patterned silver periodic nanostructures. The surface plasmon resonances (SPRs) between the upper metal silver nanoribbons or silver nano-square matrix and the BP sheet are used to achieve effective light confinement. Since the BP sheet is continuous in the structural design, the absorption response of the system can be dynamically adjusted by voltage-controlled Fermi level of BP. We also discussed two structural parameters closely related to the local size of SPR, the width of silver nanoribbons w1, and the distance d1 between silver and BP. The crystal structure of the BP puckered shows a strong in-plane anisotropy. When the silver in the system is a nanoribbon and a nano-square matrix, we research the anisotropy of the system by placing the BP in different directions relative to the structure and change the polarization angle of the incident light. The proposed anisotropic structure has the ability to achieve light confinement, which provides the basis for the construction of plasmonic sensors and polarization switches. [ABSTRACT FROM AUTHOR]

A dual-frequency on–off modulator with considerable modulation depth (MD) and relatively low insertion loss (IL) is performed with patterned monolayer graphene metamaterial. Destructive interference in this structure gives rise to the dual plasmon-induced transparency (DPIT) phenomenon. The coupled mode theory, confirmed by simulated values, is comprehensively introduced to expound the physical mechanism of the DPIT effect. In addition, the influences of the Fermi level on the DPIT transmission spectrum and the carrier mobility of graphene on the on–off modulation are researched. It is found that the dual-frequency on–off modulator exhibits remarkable modulation performance on both switches and is easier to fabricate in operation than other multi-layer graphene-based modulators. In the 'on1/off1' state, the MD and IL are 93%, 0.32 dB, respectively. In the 'on2/off2' state, the MD and IL are 85%, 0.25 dB, separately. Moreover, the property of slow light reflected by the group index is analyzed. It exhibits that the group index of the proposed structure with multi-channel can reach 358. Thus, the proposed structure stretches the versatile applications in multi-function modulators and multi-channel slow light devices at the terahertz band. [ABSTRACT FROM AUTHOR]

Both black phosphorus (BP) and graphene metamaterials support surface plasmon resonance that is very sensitive to the local change of dielectric properties in the system. We design a novel BP ribbons and graphene sheet hybrid structures based on tunable mid-infrared plasmon-induced transparency. The destructive interference of two excited state modes in the structure leads to a pronounced induced transparent window, and the excellent absorption of the two channels is obtained. The transmission characteristics of the hybrid structures are theoretical calculation, and the results are in good agreement with the numerical simulation curve. The dynamic adjustment function can be realized by adjusting the carrier density of BP and the Fermi level of graphene, and the excellent absorption performance not affected within the adjustment range. Moreover, we found that the optical phase is rapid flips at the plasmon resonance position. Therefore, a sensing medium layer is added on top of the structure to implement a high-sensitivity plasmonic biosensor. This work may provide potential applications to plasmonic devices based on two-dimensional metamaterial. [ABSTRACT FROM AUTHOR]

Friedrich-Wintgen (F W) bound states in the continuum (BICs), as a kind of optical BICs, basically relie on changing the angle of incidence and polarization for its dynamic implementation. Here, we explore the realization of an F W BIC in a hybrid guided-mode resonance (GMR) and Fabry-Pérot resonance (FPR) system consisting of two layers of graphene and dielectric SiO 2. The band structure and field distribution demonstrate the location of the proposed BIC is at 44 THz. Further studies show that changes in the Fermi level of graphene1 can dynamically achieve the F W BIC. Considering the significant difference in the electric field intensity corresponding to the GMR and F W BIC states, the dynamic near-field display can be achieved by applying different gate voltages. This work provides theoretical guidance for F W BIC in image display and data encryption. [Display omitted] • An F W BIC is realized in a hybrid guided-mode resonance and Fabry-Pérot resonancesystem. • The F W BIC can be realized dynamically by changing the Fermi level of graphene1. • The dynamic near-field display can be achieved by applying different gate voltages in the system. [ABSTRACT FROM AUTHOR]