Optical tunable multifunctional slow light device based on double monolayer graphene grating-like metamaterial

Abstract A very simple optical tunable device, which can realize multiple functions of frequency selection, reflection and slow light, is presented at the investigation. The proposed device is constructed by a periodic grating-like structure. There are two dielectrics (graphene and silicon) in a period of the equivalent grating. The incident light will strongly resonate with the graphene of electrostatic doping, forming an evanescent wave propagating along the surface of graphene, and this phenomenon is the surface plasmon. Under constructive interference of the polaritons, a unique plasmonic induced transparency phenomenon will be achieved. The induced transparency produced by this device can be well theoretically fitted by the bright and dark mode of optical equivalent cavity which can be called coupled mode theory (CMT). This theory can well analyze the influence of various modes and various losses between the function of this device. The device can use gate voltages for electrostatic doping in order to change the graphene carrier concentration and tune the optical performance of the device. Moreover, the length of the device in y-direction is will be much larger than the length of single cycle, providing some basis for realizing the fast tunable function and laying a foundation for the integration. Through a simulation and calculation, we can find that the group index and group delay of this device are as high as 515 and 0.257 picoseconds (ps) respectively, so it can provide a good construction idea for the slow light device. The proposed grating-like metamaterial structure can provide certain simulation and theoretical help for the optical tunable reflectors, absorbers, and slow light devices.

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Tunable dual plasmon-induced transparency and slow-light analysis based on monolayer patterned graphene metamaterial

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac485a ◽

2022 ◽

Author(s):

Pengju Yao ◽

Biao Zeng ◽

Enduo Gao ◽

Hao Zhang ◽

Chao Liu ◽

...

Keyword(s):

Absorption Rate ◽

Slow Light ◽

Monolayer Graphene ◽

Destructive Interference ◽

Group Index ◽

Coupled Mode ◽

External Bias ◽

Internal Mechanism ◽

Induced Transparency ◽

Plasmon Induced Transparency

Abstract We propose a novel terahertz metamaterial structure based on patterned monolayer graphene. This structure produces an evident dual plasmon-induced transparency (PIT) phenomenon due to destructive interference between bright and dark modes. Since the Fermi level of graphene can be adjusted by an external bias voltage, the PIT phenomenon can be tuned by adjusting the voltage. Then the coupled-mode theory (CMT) is introduced to explore the internal mechanism of the PIT. After that, we investigate the variation of absorption rate at different graphene carrier mobilities, and it shows that the absorption rate of this structure can reach 50%, which is a guideline for the realization of graphene terahertz absorption devices. In addition, through the study of the slow-light performance for this structure, it is found that its group index is as high as 928, which provides a specific theoretical basis for the study of graphene slow-light devices.

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Graphene-Modulated Terahertz Metasurfaces for Selective and Active Control of Dual-Band Electromagnetic Induced Reflection (EIR) Windows

Nanomaterials ◽

10.3390/nano11092420 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2420

Author(s):

Xunjun He ◽

Chenguang Sun ◽

Yue Wang ◽

Guangjun Lu ◽

Jiuxing Jiang ◽

...

Keyword(s):

Active Control ◽

Slow Light ◽

Near Field ◽

Dual Band ◽

Destructive Interference ◽

Dark Mode ◽

Field Coupling ◽

Control Scheme ◽

Electrostatic Doping ◽

Induced Transparency

Currently, metasurfaces (MSs) integrating with different active materials have been widely explored to actively manipulate the resonance intensity of multi-band electromagnetic induced transparency (EIT) windows. Unfortunately, these hybrid MSs can only realize the global control of multi-EIT windows rather than selective control. Here, a graphene-functionalized complementary terahertz MS, composed of a dipole slot and two graphene-integrated quadrupole slots with different sizes, is proposed to execute selective and active control of dual-band electromagnetic induced reflection (EIR) windows. In this structure, dual-band EIR windows arise from the destructive interference caused by the near field coupling between the bright dipole slot and dark quadrupole slot. By embedding graphene ribbons beneath two quadrupole slots, the resonance intensity of two windows can be selectively and actively modulated by adjusting Fermi energy of the corresponding graphene ribbons via electrostatic doping. The theoretical model and field distributions demonstrate that the active tuning behavior can be ascribed to the change in the damper factor of the corresponding dark mode. In addition, the active control of the group delay is further investigated to develop compact slow light devices. Therefore, the selective and active control scheme introduced here can offer new opportunities and platforms for designing multifunctional terahertz devices.

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Dual-Tunable Polarization Insensitive Electromagnetically Induced Transparency in Metamaterials

Journal of Electronic Materials ◽

10.1007/s11664-020-08692-9 ◽

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.

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Dual plasmon-induced transparency and slow light effect in monolayer graphene structure with rectangular defects

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/aae9cc ◽

2018 ◽

Vol 52 (2) ◽

pp. 025104 ◽

Cited By ~ 22

Author(s):

Hui Xu ◽

Mingzhuo Zhao ◽

Mingfei Zheng ◽

Cuixiu Xiong ◽

Baihui Zhang ◽

...

Keyword(s):

Slow Light ◽

Monolayer Graphene ◽

Light Effect ◽

Induced Transparency ◽

Plasmon Induced Transparency

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Dynamically tunable plasmon-induced transparency effect based on graphene metasurfaces

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac3f5b ◽

2021 ◽

Author(s):

Shuxian Chen ◽

Junyi Li ◽

Zicong Guo ◽

Li Chen ◽

Kunhua Wen ◽

...

Keyword(s):

Modulation Depth ◽

Incident Light ◽

Polarization Angle ◽

Refractive Index Sensitivity ◽

Coupled Mode ◽

Terahertz Devices ◽

Index Sensitivity ◽

Induced Transparency ◽

Difference Time ◽

Plasmon Induced Transparency

Abstract Plasmon-induced transparency (PIT) is theoretically explored with a graphene metamaterial using finite-difference time-domain numerical simulations and coupled-mode-theory theoretical analysis. In this work, the proposed structure is consisted of one rectangular cavity and three strips to generate the PIT phenomenon. The PIT window can be regulated dynamically by adjusting the Fermi level of the graphene. Importantly, the modulation depth of the amplitude can reach 90.4%. The refractive index sensitivity of the PIT window is also investigated, and the simulation result shows that a sensitivity of 1.335 THz/RIU is achieved. Additionally, when the polarization angle of the incident light is changed gradually from 0˚ to 90˚, the performances of the structure are greatly affected. Finally, the proposed structure is particularly enlightening for the design of dynamically tuned terahertz devices.

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Dual-Mode On-to-Off Modulation of Plasmon-Induced Transparency and Coupling Effect in Patterned Graphene-Based Terahertz Metasurface

Nanoscale Research Letters ◽

10.1186/s11671-019-3237-y ◽

2020 ◽

Vol 15 (1) ◽

Cited By ~ 31

Author(s):

Zhimin Liu ◽

Enduo Gao ◽

Zhenbin Zhang ◽

Hongjian Li ◽

Hui Xu ◽

...

Keyword(s):

Slow Light ◽

Coupling Effect ◽

Structural Parameters ◽

Fdtd Simulation ◽

Destructive Interference ◽

Dual Mode ◽

Coupled Mode ◽

Induced Transparency ◽

Difference Time ◽

Plasmon Induced Transparency

AbstractThe plasmon-induced transparency (PIT), which is destructive interference between the superradiation mode and the subradiation mode, is studied in patterned graphene-based terahertz metasurface composed of graphene ribbons and graphene strips. As the results of finite-difference time-domain (FDTD) simulation and coupled-mode theory (CMT) fitting, the PIT can be dynamically modulated by the dual-mode. The left (right) transmission dip is mainly tailored by the gate voltage applied to graphene ribbons (stripes), respectively, meaning a dual-mode on-to-off modulator is realized. Surprisingly, an absorbance of 50% and slow-light property of 0.7 ps are also achieved, demonstrating the proposed PIT metasurface has important applications in absorption and slow-light. In addition, coupling effects between the graphene ribbons and the graphene strips in PIT metasurface with different structural parameters also are studied in detail. Thus, the proposed structure provides a new basis for the dual-mode on-to-off multi-function modulators.

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

Modern Physics Letters B ◽

10.1142/s0217984914502170 ◽

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.

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Electromagnetic Induced Transparency and Slow light in Plasmonic Metasurfaces

10.21203/rs.3.rs-272442/v1 ◽

2021 ◽

Author(s):

Haseeb Ahmad Khan ◽

Syed Waqar Shah ◽

Adnan Daud Khan

Keyword(s):

Slow Light ◽

Contrast Ratio ◽

High Sensitivity ◽

Group Index ◽

Fano Resonances ◽

Higher Order Modes ◽

Effective Group ◽

Induced Transparency ◽

Fano Effects ◽

Electromagnetic Induced Transparency

Abstract We report numerically electromagnetic-induced transparency (EIT) and Fano resonances in simple plasmonic metasurfaces consist of gold nanobars arranged in Pi, H and four shaped fashion. The bright and dark elements in the metasurfaces are responsible for the emergence of EIT and Fano effects in the transmission spectrum. The concept of symmetry breaking is also introduced by incorporating multiple cavities in the metasurface, which relaxes the dipole coupling selection rules resulting in a mixture of dipole and higher order modes that interact and engenders EIT and Fano modes simultaneously in a nanostructure. Furthermore, the EIT and Fano resonances experience a significant red-shift by increasing the refractive index of the background medium due to which high sensitivity of around 574 nmRIU -1 , figure of merit of 32, and contrast ratio of 41% are realized. Moreover, the effective group index of the proposed metasurface is retrieved and is observed to be very high around the steep asymmetric Fano line shape and within the EIT window, signifying its potential use in slow light applications.

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

10.21203/rs.3.rs-777775/v1 ◽

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.

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