Analog of electromagnetically induced absorption and transparency phenomena of nonreciprocity and polarization sensitivity properties in layered topology metastructure
The nonreciprocal and polarization-sensitive performances of analog of electromagnetically induced absorption (EIA-like) and electromagnetically induced transparency (EIT-like) effects are investigated by the transfer matrix method (TMM), and the layered topology metastructure containing microwave magnetized plasma is used to construct suitable bright resonators, dark resonators, and quasi-dark resonators. In the case of low frequencies, the incident TM wave fosters an evident nonreciprocal EIA-like effect, and its nonreciprocal absorptivity is higher than 0.8, while the EIA-like phenomenon fails to occur in the case of the incident TE wave. For the case of high-frequency incidence, the EIT-like and EIA-like effects can be switched by converting the TM wave into the TE one under the case of backward propagation, and the maximum nonreciprocal absorptivity can exceed 0.9 if the TE wave propagates. The effects of some critical variables such as incident angle, plasma frequency, plasma cyclotron frequency, and plasma layer thickness on nonreciprocal and polarization-sensitive characteristics have been explored, and the slow light property of the EIT-like effect has also been briefly involved, and its group refractive index can reach 1224. The energy level transition theory and the optimized two-oscillator model are also analyzed to explain the generation of EIA-like and EIT-like phenomena in depth. We hope that the relevant phenomena will be interesting for slow light devices, two-way communication of electromagnetic waves, and polarization separation devices.
The nonreciprocal and polarization-sensitive performances of analog of electromagnetically induced absorption (EIA-like) and electromagnetically induced transparency (EIT-like) effects are investigated by the transfer matrix method (TMM), and the layered topology metastructure containing microwave magnetized plasma is used to construct suitable bright resonators, dark resonators, and quasi-dark resonators. In the case of low frequencies, the incident TM wave fosters an evident nonreciprocal EIA-like effect, and its nonreciprocal absorptivity is higher than 0.8, while the EIA-like phenomenon fails to occur in the case of the incident TE wave. For the case of high-frequency incidence, the EIT-like and EIA-like effects can be switched by converting the TM wave into the TE one under the case of backward propagation, and the maximum nonreciprocal absorptivity can exceed 0.9 if the TE wave propagates. The effects of some critical variables such as incident angle, plasma frequency, plasma cyclotron frequency, and plasma layer thickness on nonreciprocal and polarization-sensitive characteristics have been explored, and the slow light property of the EIT-like effect has also been briefly involved, and its group refractive index can reach 1224. The energy level transition theory and the optimized two-oscillator model are also analyzed to explain the generation of EIA-like and EIT-like phenomena in depth. We hope that the relevant phenomena will be interesting for slow light devices, two-way communication of electromagnetic waves, and polarization separation devices.
This paper puts forward the transmission from twin-peak electromagnetically induced transparency (EIT) to twin-peak electromagnetically induced absorption (EIA), while it is rare to see the transformation between EIT and EIA in metastructure (MS) in one device in previous articles. With the incidence of TE waves, two transparent windows are generated, ranging from 0.382 THz to 0.986 THz which are separated by 0.604 THz, when the conductivity of vanadium dioxide (VO2) is set to 10 S/m. Two peaks reach 0.864 and 0.934, respectively, accompanied by the largest group delays of the two peaks being 7.55 and 4.54 ps. In addition, VO2 blocks in the metallic state will affect interference paths between energy levels, contributing to the formation of EIA, then maintaining a common absorption of 0.607 at 0.429 THz and 0.904 at 0.678 THz. Under the combined action of the dielectric resonator and metal resonator, the conversion from bimodal EIT to bimodal EIA is hardly been researched, at the same time, the adoption of the circuit model and the four-level theory proves the rationality of the model. The transformation from EIT to EIA is aroused by changing the state of VO2, promising broad prospects in multifunctional devices.
Abstract Based on the solid-state plasma (SSP), a metamaterial analog of electromagnetically induced transparency (EIT-like) with superior properties is theoretically proposed, including tunability, a large group index, and delay-bandwidth product (DBP), polarization independence, and low-loss. By exciting different specific parts of the SSP, the EIT-like peak frequency switches from 8.518 GHz with 90.92% transmissivity in state I to 11.26 GHz with 93.76% transmissivity in state II, i.e. a 2.742 GHz shift. Meanwhile, the metamaterial has 0.679 ns or 1.314 ns group delay, 453 or 876.1 group index, and 0.422 or 1 DBP in state I or III. Additionally, the transmission curves are the same under the circular polarization waves or linear polarization waves at any angle. The low-loss feature is likewise demonstrated. Therefore, the EIT-like metamaterial has superior properties for related applications, especially in slow light, sensing, switching, and communication.
We theoretically investigate the classical analog of electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) in a planar metamaterial at optical frequency, which originates from destructive and constructive interference between dark and radiative elements.The metamaterial consists of two coupled resonators with different geometries.An EIT-like transparent window with low absorption is observed and found to be strongly affected by resonant states of the resonators.The transition between the EIT and EIA is achieved by changing the split width and coupling distance.The absorption is enhanced up to 2.5 times compared with the dipolar case.The excitation of the dark mode is very important for EIT-and EIA-like responses of the proposed metamaterial.The EIT and EIA phenomena offer a potential method for manipulating electromagnetic response in metamaterial-based devices.
Based on solid-state plasma (SSP), an electromagnetically induced transparent (EIT) metamaterial is proposed. Simulations illustrate that the given metamaterial has the characteristics of adjustment, polarization insensitivity, and low dissipation. Because SSP can be coordinated in state I, the ideal transmittance frequency band can cover 8.0335–9.02531 GHz (a narrow band). If the regulatory status is switched to state II, that frequency region will alter to 9.7982–12.9275 GHz (a broad band). As SSP can be switched back and forth between states I and II under actual demand, the tailored EIT metamaterial can be achieved. The maximum group delays of state I and state II are 0.9437 ns and 0.5546 ns, respectively, and the maximum group refractive indices are 526.60 and 300.45, respectively, which conforms to its slow light characteristic. Regardless of how the polarization angle changes, the two transmission valleys of state I are at 7.9172 GHz and 10.4446 GHz, and the transmission peak is situated at 8.2091 GHz, and those values of state II are 9.3777 GHz, 13.9600 GHz, and 10.1920 GHz, respectively, which proves that the obtained EIT is polarization independent and also has a low dissipation factor. Such an EIT metamaterial has excellent properties in sensing, communication, slow light, and other fields.
Abstract Electromagnetically induced transparency (EIT), characterised by strong dispersion and a narrow transparency window, holds great potential for developing slow light devices in communications. However, in the GHz regime, achieving a simple EIT structure with high group delay and tunability remains challenging. This paper reports an asymmetric plasma waveguide capable of producing EIT analogues, as demonstrated by finite element method simulations and a two-oscillator model (TOM). The asymmetric plasma waveguide consists of a plasma–dielectric–plasma structure with non-uniformly sized teeth. The results indicate that the EIT analogue is attributed to detuning induced by the difference in tooth size. Specifically, the detuning creates an interference band, which governs the interaction between two bright modes (i.e. resonance modes in the two teeth). The TOM aligns excellently with numerical simulations. Notably, unlike previous works, the TOM is also analysed from a fundamental energy perspective. The operating frequency can be easily tuned by adjusting plasma frequencies. The maximum group delay can reach 8.5 ns. Our study advances the understanding of the EIT phenomenon in slot waveguides with asymmetric resonators and may offer a new platform for developing actively tunable microwave slow-light devices.
In this manuscript, we demonstrate numerically classical analogy of electromagnetically induced transparency (EIT) with a windmill type metamaterial consisting of two dumbbell dielectric resonator. With proper external excitation, dielectric resonators serve as EIT bright and dark elements via electric and magnetic Mie resonances, respectively. Rigorous numerical analyses reveal that dielectric metamaterial exhibits sharp transparency peak characterized by large group index due to the destructive interference between EIT bright and dark resonators. Furthermore, such EIT transmission behavior keeps stable property with respect to polarization and incidence angles.