Realization of multiple-band terahertz metamaterial absorber using two identical split rings having opposite opening directions connected by a rectangular patch

Multiple-band metamaterial absorber at terahertz regime using periodically arranged surface structure placed on ultra-thin thickness of insulating dielectric slab backed by a metallic ground plane is demonstrated in this paper....

Guided exciton-polaritons in a subwavelength dielectric slab integrated with a 2D semiconductor

New-generation nonlinear planar polaritonic devices based on 2D semiconductors demonstrate great potential for a wide range of practical applications. In this work, we experimentally study strong light–matter coupling between waveguide photons and excitons in a photonic system based on dielectric slab waveguides integrated with 2D transition metal dichalcogenides.

Far-Field Subwavelength Straight-Line Projection/Imaging by Means of a Novel Double-Near-Zero Index-Based Two-Layer Metamaterial

In this paper, for the first time, tuned near-zero-index materials are used in a structure for the long-distance projection of very closely spaced objects with subwavelength separation. Near-zero-index materials have never been used for subwavelength projection/imaging. The proposed novel structure is composed of a two-layer slab that can project two slits with a subwavelength separation distance to a long distance without diverged/converged interference of the two imaged waves. The two-layer slab consists of a thin double-near-zero (DNZ) slab with an obtained tuned index of 0.05 and thickness of 0.04λ0 coupled with a high-index dielectric slab with specific thicknesses. Through a parametric study, the non-zero index of the DNZ layer is tuned to create a clear image when it is coupled with the high-index dielectric layer. The minimum size for the aperture of the proposed two-layer slab is 2λ0 to provide a clear projection of the two slits. The space between the slits is λ0/8, which is five times beyond the diffraction limit. It is shown that, through the conventional methods (e.g., only with high-index dielectric slabs, uncoupled with a DNZ layer), it is impossible to clearly project slits at a large distance (~λ0) due to the diffraction limit. An analytical analysis, as well as numerical results in a finite-element-based simulator, confirm the function of the proposed structure.

Theoretical model of gain calculation of active photonic-crystal microcavity waveguide

In this paper, we propose an active photonic-crystal microcavity waveguide with two-level atom-doped-dielectric slab as background material, and derive the model for signal gain calculation and analyze its gain characteristics. The analytical results show that the structure can generate high gain in a short length because of the efficient utilization of pump power in the microcavity. The proposed waveguide will be promising for the development of an active integrated photonic system.

Method of Moment Analysis of Carbon Nanotubes Embedded in A Lossy Dielectric Slab Using A Multilayer Dyadic Green’s Function

<div>Modeling the electromagnetic response of carbon nanotube (CNT) reinforced composites is inherently a three dimensional (3D) multi-scale problem that is challenging to solve in real-time for nondestructive evaluation applications. This article presents a fast and accurate full-wave electromagnetic solver based on a multi-layer dyadic Green’s function approach. In this approach, we account for the effects of the dielectric slab, where the CNTs are embedded, without explicitly discretizing its interfaces. Due to their large aspect ratios, the CNTs are modeled as arbitrary thin wires (ATWs), and the method of moment (MoM) formulation with distributed line impedance is used to solve for their coupled currents. The accuracy of the inhouse solver is validated against commercial method of moment (MoM) and finite element method (FEM) solvers over a broad range of frequencies (from 1 GHz to 10 THz) and for a wide range of dielectric slab properties. Examples of 100nm long vertical and horizontal CNTs embedded in a 1 μm thick lossy dielectric substrate are presented. The in-house solver provides more than 50 ✕ speed up while solving the vertical CNT, and more than 570 ✕ speed up while solving the horizontal CNT than a commercial MoM solver over the GHz to THz frequency range.</div>

Method of Moment Analysis of Carbon Nanotubes Embedded in A Lossy Dielectric Slab Using A Multilayer Dyadic Green’s Function

<div>Modeling the electromagnetic response of carbon nanotube (CNT) reinforced composites is inherently a three dimensional (3D) multi-scale problem that is challenging to solve in real-time for nondestructive evaluation applications. This article presents a fast and accurate full-wave electromagnetic solver based on a multi-layer dyadic Green’s function approach. In this approach, we account for the effects of the dielectric slab, where the CNTs are embedded, without explicitly discretizing its interfaces. Due to their large aspect ratios, the CNTs are modeled as arbitrary thin wires (ATWs), and the method of moment (MoM) formulation with distributed line impedance is used to solve for their coupled currents. The accuracy of the inhouse solver is validated against commercial method of moment (MoM) and finite element method (FEM) solvers over a broad range of frequencies (from 1 GHz to 10 THz) and for a wide range of dielectric slab properties. Examples of 100nm long vertical and horizontal CNTs embedded in a 1 μm thick lossy dielectric substrate are presented. The in-house solver provides more than 50 ✕ speed up while solving the vertical CNT, and more than 570 ✕ speed up while solving the horizontal CNT than a commercial MoM solver over the GHz to THz frequency range.</div>