Analog electromagnetically induced transparency for circularly polarized wave using three-dimensional chiral metamaterials

Abstract

In this paper, we theoretically and experimentally demonstrate a three-dimensional metamaterial that can motivate electromagnetic induced transparency (EIT) by using circular polarized wave as stimulations. The unit cell consists of a pair of metallic strips printed on both sides of the printed circuit board (PCB), where a conductive cylinder junction is used to connect the metal strips by drilling a hole inside the substrate. When a right circularly polarized wave is incident, destructive interference is excited between meta-atoms of the 3D structure, the transmission spectrum demonstrates a sharp transparency window. A coupled oscillator model and an electrical equivalent circuit model are applied to quantitatively and qualitatively analyze the coupling mechanism in the EIT-like metamaterial. Analysis in detail shows the EIT window's amplitude and frequency are modulated by changing the degree of symmetry breaking. The proposed metamaterial may achieve potential applications in developing chiral slow light devices.

Circularly Polarized Manipulations with VO2‐Doped Dielectric Electromagnetically Induced Transparency and Absorption

“…In EIT mode ( σ (VO 2 ) = 10 S m −1 ), interference of VO 2 ‐board can be ignored for its thickness, the dual‐coupled harmonic oscillator can be employed here to quantitatively describe the dual modes (radiative and dark modes) interactions [ 47 ] $$\begin{equation}{\ddot x_1}(t) + {r_1}\dot x(t) + {\omega _0}^2{x_1}(t) + \Omega {x_2}(t) = gE(t)\end{equation}$$ $$\begin{equation}{\ddot x_2}(t) + {r_2}\dot x(t) + ({\omega _0} + \xi ){x_2}(t) + \Omega {x_1}(t) = 0\end{equation}$$…”

“…In EIT mode (𝜎(VO 2 ) = 10 S m −1 ), interference of VO 2 -board can be ignored for its thickness, the dual-coupled harmonic oscillator can be employed here to quantitatively describe the dual modes (radiative and dark modes) interactions [47]…”

“…𝛾 1 , 𝛾 2 , and Ω correspond to oscillation dampings and the coupling strength between two oscillators, separately. Assume x 1 (t) = c 1 e j𝜔t , x 2 (t) = c 2 e j𝜔t , 𝜔 1 2 −𝜔 2 ≈ 2𝜔 1 (𝜔 1 −𝜔), (Ω is real, as the delayed phase Φ can be reduced to 0 in Equation Ω(Φ) = Ωe jΦ at normal incidence of time-harmonic electromagnetic waves) The solution to the system of equations can be expressed as [47] T = 1 − Re[ jg 2 (𝜔 − 𝜔 0 − 𝜉 + j𝛾 2 ∕2)…”

Chirality-dependent electromagnetically induced transparency based on a double semi-periodic helix metastructure

“…By adjusting the geometry parameters of the EIT metamaterials, the operating regions and dispersive properties can be manipulated. To date, previous works mainly focused on metamaterials and metastructures with linear polarization selectivity, the EIT-like phenomenon with circular polarization selectivity has been seldom involved [26,27]. Here in this letter, we propose a new type of metastructure composed of two spatial separated semi-periodic helices, from which the numerical parameter study presents a chirality dependent EIT phenomenon and slow light effect.…”

Broadband Filter and Adjustable Extinction Ratio Modulator Based on Metal-Graphene Hybrid Metamaterials

“…However, the application of EIT is extremely limited due to the fact that the generation of EIT phenomena requires harsh environmental conditions [ 17 , 18 ]. The appearance of metamaterials provides a way to realize classical analogs of electromagnetically induced transparency (EIT-like) [ 19 , 20 , 21 ]. In past decade, graphene with unique properties, particularly the conductivity of graphene, can be easily regulated by changing the Fermi level [ 22 , 23 ], and has attracted considerable attention to the active control of the EIT-like response.…”