Actively mode tunable electromagnetically induced transparency in a polarization-dependent terahertz metamaterial

Abstract

Electromagnetically induced transparency (EIT) is a quantum destructive interference phenomenon in three-level atomic systems, which can slow down the light velocity and has application prospects in information storage and processing. However, the EIT effect in atomic systems requires harsh experimental conditions. This problem can be solved by employing an EIT metamaterial, where destructive interference occurs between a bright mode and a dark mode or a quasi-dark mode, inducing a transparency window accompanied by the slow light effect. Here, we propose an actively mode tunable electromagnetically induced transparency terahertz metamaterial, which is comprised of a T-type resonator, a split-ring resonator (SRR), and coupled split-ring resonators (CSRRs). When the external electric field is vertical to the gap of the SRR (x-polarization), there is a single EIT mode accompanied by one slow light wave packet. On the other hand, when the external electric field is parallel to the gap of the SRR (y-polarization), there are two EIT modes accompanied by two slow light wave packets. Therefore, an active switch from a single EIT mode to dual EIT modes controlled by changing the polarization is demonstrated, which can find explanation from the electric field intensity distributions. This work offers a strategy to realize the mode tunable EIT, which may achieve potential applications in active filters, modulators, and slow light devices.

High-transmission and large group delay terahertz triple-band electromagnetically induced transparency in a metal-perovskite hybrid metasurface

“…However, the proposed multi-band EIT effects contain two shortcomings: first, the structures of the proposed metasurfaces are complicated in order to realize the coupling between structures; second, the transmission amplitude of the multiple transparent windows is not high, which is caused by the interference of complex metasurface. [26][27][28][29] Therefore, improving the transmission amplitudes of transparent windows is the first requirement, followed by simplifying the metasurface.…”

Theoretical proposal of electromagnetically induced transparency with a transmissive polarization conversion based on metamaterials

“…The EIT refers to a quantum destructive interference phenomenon, which is first discovered in three-level atomic systems, exhibiting a steep transmission peak whose band is narrow [9]. The EIT effect is usually accompanied by a strong dispersion and large group velocity [10]. Because of that, the EIT behavior has broad application prospects in enhancing nonlinear effects, signal processing, optical switching, optical storage [11], etc Nevertheless, the observation of the EIT phenomenon needs stern and fastidious experimental conditions in atomic systems, such as a strong laser and a lower temperature, limiting wider applications in practical engineering.…”

An Active Electromagnetically Induced Transparency (EIT) Metamaterial Based on Conductive Coupling

“…While in the metamaterial the resonant mode is usually within a narrow band, EIT effect was also usually limited in a narrow spectral range. To realize a broadband EIT effect in the metamaterial, different resonance tunable approaches have been proposed [ 23 ]. For example, Micro-Electro-Mechanical System (MEMS) technology is applied to mechanically reconfigure the micrometer scaled metamaterial unit cell structure and change the coupling between the radiative mode and the non-radiative mode [ 24 , 25 ].…”