scholarly journals Electrical Manipulation of Electromagnetically Induced Transparency for Slow Light Purpose Based on Metal-Graphene Hybrid Metamaterial

2018 ◽  
Vol 8 (12) ◽  
pp. 2672 ◽  
Author(s):  
Chenxi Liu ◽  
Song Zha ◽  
Peiguo Liu ◽  
Cheng Yang ◽  
Qihui Zhou
Keyword(s):  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
Critical Index ◽  
Hybrid Structure ◽  
Strip Width ◽  
Ring Resonators ◽  
Dark Mode ◽  
Surface Distribution ◽  
Induced Transparency ◽  
Hybrid Metamaterial

A terahertz metamaterial is presented and numerically investigated to achieve tunable electromagnetically induced transparency (EIT) for slow light. The unit cell consists of cut-wire pairs and U-shaped ring resonators with graphene strips placed between the metal film and the SiO2/Si substrate. Through bright-dark mode coupling, the radiative resonance induced by the U-shaped ring is suppressed, and then the typical EIT effect is realized. The transparency window and the accompanied group delay can be electrically manipulated with different Fermi energy of the graphene. By analyzing the surface distribution, the underlying tuning mechanism of this hybrid metamaterial is investigated in detail. Moreover, the transparency peak decreases slightly with the increasing strip width of the graphene layer but completely vanishes as the strip width exceeds the length of the covered U-shaped ring. The influence of the critical index of graphene quality, i.e., carrier mobility on the EIT effect, is considered. The results of this study may provide valuable guidance in designing and analyzing tunable EIT structures based on a metal-graphene hybrid structure for slow light purposes.

Ultra-Broadband Electromagnetically induced Transparency in Metamaterial Based on Conductive Coupling

2021 ◽  
Author(s):  
Tiantian Zheng ◽  
Zhongyin Xiao ◽  
Mingming Chen ◽  
Xiang Miao ◽  
Xiaoyu Wang
Keyword(s):  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
Type System ◽  
Surface Current ◽  
Wide Band ◽  
Light Filter ◽  
Ring Resonators ◽  
Linear Optics ◽  
Dark Mode ◽  
Induced Transparency

Abstract In this paper, a structure comprising a horizontal metal strip resonator(SR) and four C-shape ring resonators(CRRs) is proposed, obtaining a broadband electromagnetically induced transparency-like(EIT-like) effect. The SR and CRRs are classified into bright mode and dark mode depending on whether they can be directly excited by the incident electromagnetic wave. The three-level Λ -type system and electric field are used to explain the mechanism of EIT-like effect. Meanwhile, by decreasing the distance between SR and CRRs, a transparency window of 1.4THz with relative bandwidth of 91.93% is observed. It is found that when the bright and dark mode are directly contacted, the EIT window increases rapidly via conductive coupling, which can be explained by the surface current. Our work provides a new method for wide band EIT-like effect, which has certain value in the field of slow light, filter and non-linear optics.

scholarly journals Dual-Tunable Polarization Insensitive Electromagnetically Induced Transparency in Metamaterials

2021 ◽  
Author(s):  
Renxia Ning ◽  
Zhiqiang Xiao ◽  
Zhenhai Chen ◽  
Wei Huang
Keyword(s):  
Vanadium Dioxide ◽  
Mode Coupling ◽  
Slow Light ◽  
Chemical Potential ◽  
Electromagnetically Induced Transparency ◽  
Dark Mode ◽  
Potential Applications ◽  
Polarization Insensitive ◽  
Terahertz Devices ◽  
Induced Transparency

AbstractA multilayer structure of a square ring of graphene with nesting vanadium dioxide (VO2) was investigated in this study. This structure exhibits electromagnetically induced transparency (EIT), which stems from a bright mode coupling with a dark mode. The permittivity values of graphene and VO2 can be modulated via chemical potential and temperature, respectively. The EIT effect can be tuned based on the chemical potential of graphene and temperature of VO2, resulting in a dual-tunable EIT effect. Simulation results confirmed that this dual-tunable EIT phenomenon is insensitive to polarization. These results may have potential applications in terahertz devices, such as slow light devices, switching devices, and sensors.

Investigating the direct coupling between plasmonic cavities in the case of the second-order resonant mode

2014 ◽  
Vol 28 (27) ◽  
pp. 1450217
Author(s):  
Zhihui He ◽  
Hongjian Li ◽  
Shiping Zhan ◽  
Guangtao Cao ◽  
Boxun Li
Keyword(s):  
Coupling Strength ◽  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
Resonant Mode ◽  
Second Order ◽  
Direct Coupling ◽  
Dark Mode ◽  
High Order Resonance ◽  
Light Effects ◽  
Induced Transparency

In this paper, we present a metal-dielectric-metal (MDM) waveguide side-coupled with bright-dark-bright mode cavities and double bright-dark mode cavities. The former shows a prominent plasmonic analogue of electromagnetically induced transparency (EIT) spectra response, the latter shows double plasmonic analogue of EIT spectra response. The direct coupling strength between bright and dark mode resonators in the case of the second-order resonant mode is investigated in detail in our researches. The transmission spectrum and the slow light effects as a function of the cavity–cavity separation between resonators are further studied. Our researches investigate the coupling strength effects on the transmission and scattering properties in the case of the high-order resonance mode, which may provide a guideline for the control of light in highly integrated optical circuits.

scholarly journals Numerical and Theoretical Study of Tunable Plasmonically Induced Transparency Effect Based on Bright–Dark Mode Coupling in Graphene Metasurface

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 232 ◽  
Author(s):  
Qichang Ma ◽  
Jianan Dai ◽  
Aiping Luo ◽  
Weiyi Hong
Keyword(s):  
Slow Light ◽  
Theoretical Calculations ◽  
Complex Surface ◽  
Infrared Region ◽  
Ring Resonators ◽  
Geometrical Parameters ◽  
Dark Mode ◽  
Graphene Layers ◽  
Induced Transparency ◽  
Plasmonically Induced Transparency

In this paper, we numerically and theoretically study the tunable plasmonically induced transparency (PIT) effect based on the graphene metasurface structure consisting of a graphene cut wire (CW) resonator and double split-ring resonators (SRRs) in the middle infrared region (MIR). Both the theoretical calculations according to the coupled harmonic oscillator model and simulation results indicate that the realization of the PIT effect significantly depends on the coupling distance and the coupling strength between the CW resonator and SRRs. In addition, the geometrical parameters of the CW resonator and the number of the graphene layers can alter the optical response of the graphene structure. Particularly, compared with the metal-based metamaterial, the PIT effect realized in the proposed metasurface can be flexibly modulated without adding other actively controlled materials and reconstructing the structure by taking advantage of the tunable complex surface conductivity of the graphene. These results could find significant applications in ultrafast variable optical attenuators, sensors and slow light devices.

Wideband and multiband electromagnetically induced transparency in graphene metamaterials

2019 ◽  
Vol 33 (09) ◽  
pp. 1950068 ◽  
Author(s):  
Renxia Ning ◽  
Xiang Gao ◽  
Zhenhai Chen
Keyword(s):  
Communication Technology ◽  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
Microwave Frequency ◽  
Ring Resonators ◽  
Group Index ◽  
Frequency Range ◽  
Split Ring ◽  
Structure Lead ◽  
Induced Transparency

A multiband tunable electromagnetic induced transparency (EIT) effect in metamaterial at microwave frequency range is investigated. The sandwich structure contains silicon dioxide and gold layers. The metamaterial structure has multiband EIT phenomenon due to coupling with U-Shaped split-ring resonators (SRRs) and cut wire (CW). Two different modes can be obtained in CW and a single band EIT effects in SRRs. Results show that the different resonances in the structure lead to multiband EIT. By adding the finding of the graphene layer on top of the structures, EIT window can be changed obviously. It is shown that the graphene can adjust EIT phenomenon. The group index is calculated to exhibit the slow light effect. The demonstrated phenomenon can provide valuable variety of important applications, including microwave communication technology, microwave devices, slow light and switch devices.

scholarly journals Active Electromagnetically Induced Transparency Effect in Graphene-Dielectric Hybrid Metamaterial and Its High-Performance Sensor Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2032
Author(s):  
Fan Gao ◽  
Peicheng Yuan ◽  
Shaojun Gao ◽  
Juan Deng ◽  
Zhiyu Sun ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
High Refractive Index ◽  
Infrared Region ◽  
Refractive Index Sensitivity ◽  
Index Sensitivity ◽  
Induced Transparency ◽  
Hybrid Metamaterial

Electromagnetically induced transparency (EIT) based on dielectric metamaterials has attracted attentions in recent years because of its functional manipulation of electromagnetic waves and high refractive index sensitivity, such as high transmission, sharp phase change, and large group delay, etc. In this paper, an active controlled EIT effect based on a graphene-dielectric hybrid metamaterial is proposed in the near infrared region. By changing the Fermi level of the top-covered graphene, a dynamic EIT effect with a high quality factor (Q-factor) is realized, which exhibits a tunable, slow, light performance with a maximum group index of 2500. Another intriguing characteristic of the EIT effect is its high refractive index sensitivity. In the graphene-covered metamaterial, the refractive index sensitivity is simulated as high as 411 nm/RIU and the figure-of-merit (FOM) is up to 159, which outperforms the metastructure without graphene. Therefore, the proposed graphene-covered dielectric metamaterial presents an active EIT effect in the near infrared region, which highlights its great application potential in deep optical switching, tunable slow light devices, and sensitive refractive index sensors, etc.

scholarly journals Experimental Demonstration of Electromagnetically Induced Transparency in a Conductively Coupled Flexible Metamaterial with Cheap Aluminum Foil

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Jie Hu ◽  
Tingting Lang ◽  
Weihang Xu ◽  
Jianjun Liu ◽  
Zhi Hong
Keyword(s):  
Electromagnetically Induced Transparency ◽  
Near Field ◽  
Surface Current ◽  
Aluminum Foil ◽  
Ring Resonators ◽  
Dark Mode ◽  
Field Coupling ◽  
New Ideas ◽  
Induced Transparency ◽  
Bright Mode

AbstractWe propose a conductively coupled terahertz metallic metamaterial exhibiting analog of electromagnetically induced transparency (EIT), in which the bright and dark mode antennae interact via surface currents rather than near-field coupling. Aluminum foil, which is very cheap and often used in food package, is used to fabricate our metamaterials. Thus, our metamaterials are also flexible metamaterials. In our design, aluminum bar resonators and aluminum split ring resonators (SRRs) are connected (rather than separated) in the form of a fork-shaped structure. We conduct a numerical simulation and an experiment to analyze the mechanism of the proposed metamaterial. The surface current due to LSP resonance (bright mode) flows along different paths, and a potential difference is generated at the split gaps of the SRRs. Thus, an LC resonance (dark mode) is induced, and the bright mode is suppressed, resulting in EIT. The EIT-like phenomenon exhibited by the metamaterial is induced by surface conducting currents, which may provide new ideas for the design of EIT metamaterials. Moreover, the process of fabricating microstructures on flexible substrates can provide a reference for producing flexible microstructures in the future.

scholarly journals Electromagnetically Induced Transparency-Like Effect by Dark-Dark Mode Coupling

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1350
Author(s):  
Qiao Wang ◽  
Kaili Kuang ◽  
Huixuan Gao ◽  
Shuwen Chu ◽  
Li Yu ◽  
...  
Keyword(s):  
Mode Coupling ◽  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
Research Area ◽  
Destructive Interference ◽  
Dark Mode ◽  
Metal Grating ◽  
Layer 4 ◽  
Induced Transparency ◽  
Waveguide Resonance

Electromagnetically induced transparency-like (EIT-like) effect is a promising research area for applications of slow light, sensing and metamaterials. The EIT-like effect is generally formed by the destructive interference of bright-dark mode coupling and bright-bright mode coupling. There are seldom reports about EIT-like effect realized by the coupling of two dark modes. In this paper, we numerically and theoretically demonstrated that the EIT-like effect is achieved through dark-dark mode coupling of two waveguide resonances in a compound nanosystem with metal grating and multilayer structure. If we introduce |1〉, | 2 〉 and | 3 〉 to represent the surface plasmon polaritons (SPPs) resonance, waveguide resonance in layer 2, and waveguide resonance in layer 4, the destructive interference occurs between two pathways of | 0 〉 → | 1 〉 → | 2 〉 and | 0 〉 → | 1 〉 → | 2 〉 → | 3 〉 → | 2 〉 , where | 0 〉 is the ground state without excitation. Our work will stimulate more studies on EIT-like effect with dark-dark mode coupling in other systems.

scholarly journals All-optical tunable slow-light based on analogue of electromagnetically induced transparency in a hybrid metamaterial

2021 ◽  
Author(s):  
Chengju Ma ◽  
Yuebin Zhang ◽  
Yao Zhang ◽  
Shiqian Bao ◽  
Jiasheng Jin ◽  
...  
Keyword(s):  
Slow Light ◽  
Electromagnetically Induced Transparency ◽  
All Optical ◽  
Induced Transparency ◽  
Hybrid Metamaterial

We demonstrate and analyze the use of metamaterials with analogue of electromagnetically induced transparency (EIT) on slow light technology. For the most metamaterials, EIT-like effects suffer from the intrinsic Ohmic...

Probing Bloch oscillations using a slow-light sensor

2020 ◽  
Vol 9 (5) ◽  
pp. 243-246
Author(s):  
Pei-Chen Kuan ◽  
Chang Huang ◽  
Shau-Yu Lan
Keyword(s):  
Phase Shift ◽  
Optical Lattice ◽  
Cold Atoms ◽  
Slow Light ◽  
Internal State ◽  
Electromagnetically Induced Transparency ◽  
Bloch Oscillations ◽  
Bloch Oscillation ◽  
Induced Transparency ◽  
Transparency Condition

AbstractWe implement slow-light under electromagnetically induced transparency condition to measure the motion of cold atoms in an optical lattice undergoing Bloch oscillation. The motion of atoms is mapped out through the phase shift of light without perturbing the external and internal state of the atoms. Our results can be used to construct a continuous motional sensor of cold atoms.

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