Enhanced THz EIT resonance based on the coupled electric field dropping effect within the undulated meta-surface

Abstract

In this paper, the enhanced terahertz (THz) electromagnetically induced transparency (EIT) resonance is achieved based on the coupled electric field dropping effect within the undulated meta-surface. It is found that the height difference between the inner ring and the outer split ring could lead to a significant coupled mode with electric field dropping distribution. When the height of the inner ring increases, the electric field of the inner ring gradually cascades to the outer ring just as a waterfall so that the coupling between the two rings in a unit cell and two adjacent units is enhanced. Both the simulation and experimental results show that a nearly 95% transparency window which is twice that of traditional EIT can be observed by applying such coupled electric field dropping effect, which may provide a promising way to develop the high resonance intensity meta-surface in the THz region.

Electromagnetically Induced Transparency Analog of Asymmetric Perovskite Metamaterial in the THz Spectral Region

“…By adjusting the asymmetry parameter, the EIT-like effect in the perovskite MM structure could be controlled. Unlike previous studies [2,[47][48][49][50][51] on the EIT-like effect, it was found that there is a maximum value for the coupling strength between bright-dark modes. This implies that there is a region where the coupling strength increases or decreases with changes to the asymmetry parameter.…”

“…In the near-field coupling between bright and dark modes, the incident wave excites the bright mode, which transfers electromagnetic energy to the dark mode. This interaction can be described by the linearly coupled Lorentz harmonic oscillator model [49][50][51][52]:…”

“…In a lossless model, the effect of the coupling strength Ω on the spectral width of the transparency window can be analyzed by ω + = ω 2 0 + Ω 2 and ω − = ω 2 0 − Ω 2 . The width of the transparency window is given by [51]…”

Multi-Band Electromagnetically-Induced-Transparency Metamaterial Based on the Near-Field Coupling of Asymmetric Split-Ring and Cut-Wire Resonators in the GHz Regime

“…Traditionally, in order to create a single-band EIT-MM, the requirement is an MM structure consisting of, at least, two different types of resonators [26,27]. So far, to our knowledge, most of the multi-band EIT-MMs have exploited more than three different types of resonators in the structure [28][29][30].…”