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[IEEE 2019 6th International Conference on Space Science and Communication (IconSpace) - Johor Bahru, Malaysia (2019.7.28-2019.7.30)] 2019 6th International Conference on Space Science and Communication (IconSpace) - Koch Fractal Loop Circular Polarization (CP) Antenna Integrated with Solar Cells
摘要： Minimal profile antennas for wireless devices which characteristics consisted of being low cost, highly reliable, and lightweight, it bears a new challenge for the design of the antenna in wireless communications. In this paper, we propose a design of circularly polarized microstrip patch antenna integration with solar cells for green wireless applications. Two techniques have been proposed to form the prototype between the communication system (design of antenna) and solar panel (solar cell). Both methods will face two issues generally; the solar system needs to get 100% sunlight and the magnetic field produced by radio communication systems as well as the electric field produced by solar cells should not affect the efficiency. The antenna is composed of a Koch fractal loop patch and the substrate is employed using a transparent material. This enables the light to pass through with high efficiency to illuminate the solar panel cells while the RF performance is maintained with minimal degradation. The communication frequency measures 2.6, 3.5 and 4.4 GHz. CST MWS simulation is also studied and compared among the different substrates which show different results based on the same parameters, which is implemented with a lattice of 2×2 square solar cells. With this arrangement, the solar cells will be able to obtain 100% of sunlight exposure. The characteristics of the broadband are achieved by combining resonances and the minimum axial ratio points created by the driven patch and solar cell surface.
关键词： Trade-off RF transparency,Wireless communication,transparent substrate,Microstrip patch antenna,Compact Meshed patch antenna,integration antenna and solar panel,CST MWS,performances and Frequency,Gain
更新于2025-09-12 10:27:22
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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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Graphene plasmonically induced analogue of tunable electromagnetically induced transparency without structurally or spatially asymmetry
摘要： Graphene plasmonically induced analogue of tunable electromagnetically induced transparency without structurally or spatially asymmetry. Electromagnetically induced transparency (EIT) arises from the coherent coupling and interference between a superradiant (bright) mode in one resonator and a subradiant (dark) mode in an adjacent resonator. Generally, the two adjacent resonators are structurally or spatially asymmetric. Here, by numerical simulation, we demonstrate that tunable EIT can be induced by graphene ribbon pairs without structurally or spatially asymmetry. The mechanism originates from the fact that the resonate frequencies of the bright mode and the dark mode supported by the symmetrical graphene ribbon pairs can be respectively tuned by electrical doping levels, and when they are tuned to be equal the graphene plasmon coupling and interference occurs. The EIT in symmetrical nanostructure which avoids deliberately breaking the element symmetry in shape as well as in size facilitates the design and fabrication of the structure. In addition, the work regarding to EIT in the structurally symmetric could provide a fresh contribution to a more comprehensive physical understanding of Fano resonance.
关键词： Electromagnetically induced transparency,Fano resonance,Tunable,Graphene,Plasmonics
更新于2025-09-12 10:27:22
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Nonreciprocity in a strongly coupled three-mode optomechanical circulatory system
摘要： In this work, we propose a scheme in three-mode optical systems to simulate a strongly coupled optomechanical system. The nonreciprocity observed in such a three-mode optomechanical circulatory system (OMCS) is explored. To be speci?c, we ?rst derive a quantum Langevin equation (QLE) for the strongly coupled OMCS by suitably choosing the laser ?eld, then we give a condition for the frequency of the laser and the mechanical decay rate, beyond which the optomechanical system has a unidirectional transmission regardless of how strong the optomechanical coupling is. The optomechanically induced transparency is also studied. The present results can be extended to a more general two-dimensional optomechanical system and a planar quantum network, and the prediction is possible to be observed in an optomechanical crystal or integrated quantum superconducting circuit. This scheme paves a way for the construction of various quantum devices that are necessary for quantum information processing.
关键词： Nonreciprocity,quantum Langevin equation,optomechanically induced transparency,quantum information processing,optomechanical circulatory system
更新于2025-09-12 10:27:22
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Multifunctional semitransparent organic solar cells with excellent infrared photon rejection
摘要： Semitransparent organic solar cells (ST-OSCs) have the potentials to open promising applications that differ from those of conventional inorganic ones, such as see-through power windows with both energy generation and heat insulation functions. However, to achieve so, there remain significant challenges, especially for balancing critical parameters, such as power conversion efficiency (PCE), average visible transparency (AVT) and low energy infrared photon radiation rejection (IRR) to realize the full potentials of ST-OSCs. Herein, we demonstrate the new design of ST-OSCs through the rational integration of organic materials, transparent electrode and infrared photon reflector in one device. With the assistance of optical simulation, new ST-OSCs with precise layout exhibit state-of-art performance, with near 30% AVT and PCE of 7.3%, as well as an excellent IRR of over 93% (780–2500 nm), representing one of best multifunctional ST-OSCs with promising perspective for window application.
关键词： Distributed Bragg reflector,Semitransparent organic solar cell,Ultrathin silver,Average visible transparency,Infrared radiation rejection
更新于2025-09-12 10:27:22
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Electromagnetically induced transparency, absorption, and microwave-field sensing in a Rb vapor cell with a three-color all-infrared laser system
摘要： A comprehensive study of three-photon electromagnetically induced transparency (EIT) and absorption (EIA) on the rubidium cascade 5S1/2 → 5P3/2 (laser wavelength 780 nm), 5P3/2 → 5D5/2 (776 nm), and 5D5/2 → 28F7/2 (1260 nm) is performed. The 780-nm probe and 776-nm dressing beams are counteraligned through a Rb room-temperature vapor cell, and the 1260-nm coupler beam is co- or counteraligned with the probe beam. Several cases of EIT and EIA, measured over a range of detunings of the 776-nm beam, are studied. The observed phenomena are modeled by numerically solving the Lindblad equation, and the results are interpreted in terms of the probe-beam absorption behavior of velocity- and detuning-dependent dressed states. Interaction-time effects are discussed. To explore the utility of three-photon Rydberg EIA and EIT for microwave electric-?eld diagnostics, a sub-THz ?eld generated by a signal source and a frequency quadrupler is applied to the Rb cell. The 100.633-GHz ?eld resonantly drives the 28F7/2 ? 29D5/2 transition and causes Autler-Townes splittings in the Rydberg EIA and EIT spectra, which are measured and employed to characterize the performance of the microwave quadrupler.
关键词： Rb vapor cell,absorption,three-color all-infrared laser system,microwave-?eld sensing,electromagnetically induced transparency
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - High Efficiency Quantum Memory in Multiplexed Large-OD Cold Atomic Ensemble
摘要： Quantum memories enabling the storage of an input photonic qubit and its later retrieval with a ?delity beating any classical device constitute essential components in quantum communication networks and optical quantum information processing [1]. Our main goal is to develop a new generation of memories which have a near-unity ef?ciency for storage-and-retrieval operations, as well as high multiplexing capabilities. In the recent years, we demonstrated for instance the implementation for quantum bits encoded in the orbital angular momentum degree of freedom, which provides an essential capability for future networks with multimode capability [2]. We also realized multiple-degree-of-freedom memory, which can ?nd applications in classical data processing but also in quantum network scenarios where states structured in phase and polarization have been shown to provide promising attributes [3]. Recently, we realized a multiplexed quantum memory for polarization encoded qubits with high storage-and-retrieval ef?ciency [4]. We report on a quantum memory for polarization qubits that combines an average conditional ?delity above 99% and ef?ciency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. The reported ef?ciency approaches the maximal performance achievable on the D2 line transition used here, as shown by a comprehensive model that includes all the involved atomic transitions. In the alkali-metal atoms, hyper?ne interaction in the excited state indeed introduces several levels which can have a strong effect on the medium susceptibility via off resonant excitation, thereby decreasing the ef?ciency when the optical depth (OD) is large. As shown by this model, switching to the D1 line can increase the ef?ciency above 90%. Preliminary results with optical depth around 400 led us to a storage-and-retrieval ef?ciency of 85% at the single-photon level.
关键词： Large-OD,Quantum memory,Polarization qubits,Multiplexed,Cesium atoms,Cold atomic ensemble,Electromagnetically-induced transparency
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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Tunable and Polarization-Independent Plasmon-Induced Transparency in a Fourfold Symmetric Metal-Graphene Terahertz Metamaterial
摘要： The introduction of graphene into metamaterials allows for more flexible and convenient control of electromagnetic waves. In this paper, one simple plasmon-induced transparency (PIT) structure with tunability and polarization independence is investigated in the terahertz (THz) regime. The simulation results indicate that the transparent window can be manipulated in a wide range and even switched off by merely changing the Fermi energy of graphene. By continuously altering the resonance intensity of the dark resonator using the graphene, the PIT resonance can be actively manipulated. The behavior can be elucidated by the classical coupled two-particle model, which corresponds well to the simulation results. Owing to the fourfold symmetric structure, the proposed PIT device exhibits polarization-independent characteristics. This work provides design guidance for metal-graphene THz modulators.
关键词： polarization-independent,metamaterial,plasmon-induced transparency,graphene
更新于2025-09-11 14:15:04
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Effects of hole-boring and relativistic transparency on particle acceleration in overdense plasma irradiated by short multi-PW laser pulses
摘要： Propagation of short and ultraintense laser pulses in a semi-infinite space of overdense hydrogen plasma is analyzed via fully relativistic, real geometry particle-in-cell (PIC) simulations including radiation friction. The relativistic transparency and hole-boring regimes are found to be sensitive to the transverse plasma field, backward light reflection, and laser pulse filamentation. For laser intensities approaching I (cid:2) 1024 W/cm2, the direct laser acceleration of protons, along with ion Coulomb explosion, results in their injection into the acceleration phase of the compressed electron wave at the front of the laser pulses. The protons are observed to be accelerated up to 10–20 GeV with densities around a few times the critical density. The effect qualitatively depends on initial density and laser intensity, disappearing with the initial density increase or intensity decrease.
关键词： particle acceleration,hole-boring,overdense plasma,laser pulses,relativistic transparency
更新于2025-09-11 14:15:04