- 标题
- 摘要
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- 实验方案
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Tunable slow light effect based on dual plasmon induced transparency in terahertz planar patterned graphene structure
摘要： We have studied a simple novel graphene ribbon structure. A very excellent and prominent dual graphene plasmon induced transparency phenomenon could be achieved by the destructive interference resulted from the excited plasmonic modes in terahertz band. Using the simple relationship between graphene and applied voltage, a good tunable effect of this structure can be achieved. The transmission of this proposed structure is theoretically investigated by using the equivalent resonator coupled mode method. The theoretical data from our proposed method are in good agreement with the numerical simulation results. Moreover, utilizing the high dispersion property, we have also researched the slow light effect for this proposed system. The results of theoretical research have indicated that the group refractive index of our proposed structure can maintain an excellent numerical value. This investigation can play a significant role in the tunable graphene-based slow light devices.
关键词： Graphene planar metamaterial,Plasmon-induced transparency,Slow light device
更新于2025-09-12 10:27:22
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MODE SPLITTING BASED ON THE COUPLING BETWEEN MODES OF TWO NANODISKS CAVITIES AND A PLASMONIC WAVEGUIDE
摘要： A metal-insulator-metal (MIM) plasmonic waveguide coupled with two nanodisks as a resonator has been examined and numerically simulated with the ?nite-di?erence time-domain (FDTD) and analytically by the Temporal Coupling Mode Theory (CMT). Based on the three-level system, the strong destructive interference between the two resonators leads to the distinct mode splitting response. The characteristics of mode splitting show that there is anomalous dispersion with the novel fast-light feature at the resonance. Meanwhile, the slow light characteristic can also be achieved in the system at wavelengths of the split modes. The relationship between the transmission characteristics and the geometric parameters is examined. The results show that the modulation depth of the mode splitting transmission spectrum of 80% with 0.175 ps fast-light e?ect of resonance can be achieved, while for the two modes these values are around 30% with ?0.18 ps slow light-e?ect. There is a good agreement between the FDTD simulated transmission features and CMT. The characteristics of the system indicate critical potential applications in integrated optical circuits such as slow-light and fast-light devices, optical monitoring, an optical ?lter, and optical storage.
关键词： slow-light,plasmonic waveguide,FDTD,mode splitting,CMT,fast-light,nanodisks
更新于2025-09-11 14:15:04
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Plasmon induced transparency like transmission properties in compact MIM waveguide side-coupled with U-cavity
摘要： Surface plasmon polaritons (SPPs) can overcome the limitation of diffraction and control light at nanoscale, thus becoming a hotspot in recent years. SPPs based metal-insulator-metal (MIM) plasmonic waveguides using U-cavity and slot cavity are designed. The transmission characteristics are numerically simulated and verified by the coupled mode theory (CMT). Meanwhile, the effects of changing the geometric parameters on the transmission characteristics are also studied. Single and double plasmon induced transparency (PIT) effects are realized through the coupling and the destructive interfering between the transmission paths. Furthermore, characteristics of the refractive index sensing as well as the slow light and fast light effects are also investigated. We hope the designed waveguide structures along with their transmission characteristics have potential application prospects in the area of nanoscale integrated optical devices, such as filters, sensors, switches, slow/fast light devices, and other optoelectronic circuits.
关键词： refractive index sensing,slow light,U-cavity,Surface plasmon polaritons,slot cavity,plasmon induced transparency,MIM plasmonic waveguides,fast light
更新于2025-09-11 14:15:04
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Active control of electromagnetically induced transparency based on terahertz hybrid metal-graphene metamaterials for slow light applications
摘要： Recently, the dynamically controlled electromagnetically induced transparency (EIT) metamaterials have been widely used in the slow light effect field to enhance the light-matter interactions and nonlinear effects, which has aroused the great attraction of many researchers. The emergence of two-dimensional materials has pushed this research to a new research hot again. Therefore, a terahertz hybrid metal-graphene metamaterial, consisting of a bi-layer metallic EIT metamaterial, an unpatterned monolayer graphene, and an encapsulated ion-gel layer, was proposed to actively control the EIT resonance. In this structure, the transparency peak of the bi-layer metallic EIT metamaterial can realize on-to-off switch through shifting the Fermi energy of graphene covering onto the dark mode resonators. Theoretical analysis and surface current distributions reveal that the active modulation can be attributed to the increasing damping rate of the dark mode caused by the actively controllable conductivity of the graphene. In addition, the active control of the group delay in the hybrid metamaterial is also demonstrated for the slow-light applications. Therefore, this work provides an alternative way to design compact slow-light devices for future terahertz wireless communications.
关键词： slow light,graphene,EIT,terahertz,Metamaterial
更新于2025-09-11 14:15:04
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European Microscopy Congress 2016: Proceedings || Angle-resolved cathodoluminescence of plasmonic crystal waveguide
摘要： Slow-light manipulation in a photonic crystal (PhC) waveguide is expected to improve future optical information processing and communication technologies such as optical buffering and light compression [T. Baba, Nat. Photon. 2, 465-473 (2008)]. Waveguiding using bandgap of plasmonic crystal (PlC) has also been demonstrated [S. I. Bozhevolnyi et al. Phys. Rev. Lett. 86, 3008-3001 (2001)]. However, the dispersion characteristics of the guided modes, which are essential to control surface plasmon polariton (SPP) pulses, have not yet been understood. Electron beam spectroscopies at high spatial resolution are powerful characterization tools to observe electromagnetic modes nowadays. Momentum-resolved spectroscopy in electron microscopy is especially useful to investigate detailed optical properties of locally-modified structures introduced into a PhC [R. Sapienza et al. Nat. Mater. 11, 781-787 (2012)] and a PlC [H. Saito and N. Yamamoto, Nano Lett. 15, 5764-5769 (2015)]. We have studied the dispersion characteristics of SPPs in a PlC waveguide by angle-resolved chatodoluminescence performed in a STEM. The guided SPP modes were found to have two unique features : i) energy dependence of the phase shift at the wall, and ii) waveguide bandgap (WBG) due to the periodicity originating from PlC structure, which resulted in small group velocity of the guided SPP modes over a wide energy range.
关键词： Slow light,Plasmonic crystal,Cathodoluminescence,Waveguide,Momentum-resolved spectroscopy
更新于2025-09-11 14:15:04
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Development of Non-Mechanical Beam Steering and LiDAR Based on Photonic Crystal and Si Photonics
摘要： LiDAR is crucial for future robots/drones, autonomous vehicles, etc. Photonic crystal and Si photonics technologies have potential of non-mechanical beam steering and coherent FMCW LiDAR. We report the current status of their development.
关键词： slow light,FMCW,LiDAR,photonic crystal,beam steering
更新于2025-09-11 14:15:04
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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Design of near-zero GVD slow light photonic crystal waveguides
摘要： Slow light propagation throughout photonic crystal slab waveguides have great potential to reduce the size and power consumption of active silicon photonic devices. A great effort has been done to understand the slow light mechanisms and their relations with the waveguide geometrical parameters. In this way, it is expected to control the waveguide dispersion characteristics and exploit the effects produced when slowing down light propagation speed, but avoiding, at the same time, the high group velocity dispersion (GVD) level drawbacks such as pulse broadening and distortion. Here, we present a concise methodology to perform an ef?cient near-zero GVD slow light photonic crystal waveguide oriented-design. We use a slow light ?atness parameter for enabling a systematic comparison of slow light waveguide structures regarding their average group velocity and group index slope within a limited bandwidth. The results show the feasibility of obtain near-zero GVD slow light photonic crystal waveguide structures with slowdown factors up to 40, normalized delay-bandwidth products over 0.2, and dispersion lengths at the millimeter scale.
关键词： Waveguide,Slow Light,Photonic Crystal
更新于2025-09-11 14:15:04
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Transmission Enhanced Wavelength Demultiplexer Design Based on Photonic Crystal Waveguide with Gradually Varied Width
摘要： In this study, we propose the design of photonic crystals with linearly tapered waveguide such that waveguide width is gradually varied. Four drop-channels are included to implement wavelength demultiplexing applications. Here, a tapering of the waveguide has been chosen to localize propagating light within the desired positions. Afterwards, the corresponding drop-channels have been opened to confine the light with the targeted wavelengths. The designed structure consists of cylindrical alumina (Al2O3) dielectric rods and operates at microwave frequencies between 13.2 GHz and 15.3 GHz. An optimization algorithm is applied to enhance transmission efficiencies of the drop-channels and to minimize possible cross-talks between the channels by optimally modulating the position of the dielectric rods inside the channels which form cavity-coupling regions. The optimization algorithm is incorporated with the finite-difference time-domain method to evaluate the transmission efficiencies of the drop-channels for the instant designed structure. The physical mechanism of wavelength demultiplexing is related to slowing down and trapping of light in the tapered waveguide and its coupling to drop-channels for selected microwave wavelengths at different positions. Moreover, an experimental verification of the numerical analyses is demonstrated in the microwave regime and corresponding results will be shared in the conference.
关键词： drop-channels,slow light,microwaves,photonic crystals,optimization,wavelength selective devices
更新于2025-09-11 14:15:04
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Broadband LWIR and MWIR absorber by trapezoid multilayered grating and SiO2 hybrid structures
摘要： A broadband metamaterial absorber with high absorption simultaneously in mid-wave infrared (MWIR) and long-wave infrared (LWIR) was proposed. In the MWIR, the absorption higher than 0.8 is from 4 to 6.3 μm, while the absorption in the LWIR is from 8.7 and 9.6 μm. The absorber is insensitive to the incident angle. The broadband absorption in the MWIR is due to the slow-light effect of the trapezoid multilayered grating structure. And the broadband absorption in the LWIR is due to the phonon polariton resonant of trapezoid SiO2 layer. In the broadband high absorption region, the atmosphere is transparent, which may greatly promote the practical application of the absorber in double-color IR imaging, detecting, infrared stealth and thermal emitting.
关键词： Metamaterial,Transparent atmosphere window,Broadband absorber,Slow-light effect,Phonon polariton resonant
更新于2025-09-10 09:29:36
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Electrical Manipulation of Electromagnetically Induced Transparency for Slow Light Purpose Based on Metal-Graphene Hybrid Metamaterial
摘要： 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.
关键词： slow light,electromagnetically induced transparency,graphene,metamaterial
更新于2025-09-04 15:30:14