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Metamaterial Mirror as Back Reflector for Thin Silicon Solar Cell Application
摘要： Metamaterial mirrors as back reflector is an innovative design for light trapping phenomenon in thin silicon solar cells. An optimized design for achieving maximum reflection in such metamaterial mirror is presented in this paper. In conventional metallic mirrors when light is reflected a phase reversal occurs and thus the intensity is reduced at the reflective surface. This effect is highly undesirable in thin solar cell applications where metal is used both as an electrical contact and an optical mirror. A mirror whose reflection phase can be varied from a perfect electric mirror (conventional metallic mirror) to that of a perfect magnetic mirror can be used to overcome this challenge in thin silicon solar cells. In a magnetic mirror no phase reversal of the incident electromagnetic wave occurs resulting in maximum electric field enhancement at the mirror surface. Such magnetic mirrors are classified as metamaterial mirrors. Simulations have been done with ComsolMultiphysics to obtain electric field and reflection for both TE (Transverse Electric) and TM (Transverse Magnetic) polarized light to obtain the optimized geometry. The generation rate and phase conservation has been observed from simulation when magnetic mirror is placed at the back of silicon substrate. The enhancement in the electric field is significantly increased which will lead to an enhanced absorption in the thin solar absorber resulting in high efficiencies.
关键词： solar cell,phase reversal,Metamaterial mirror,magnetic mirror,electric mirror
更新于2025-09-12 10:27:22
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Numerical study of a high negative refractive index based tunable metamaterial structure by graphene split ring resonator for far infrared frequency
摘要： We present a numerical study of a high negative effective refractive index based actively tunable squared shaped graphene split ring resonator for far infrared frequency spectrum. Graphene split ring resonator (GSRR) structure is investigated for the different cases of the split rings. Tunability of the structure is controlled by varying the different chemical potential of the graphene sheet, which can be controlled by external potential. Transmission, Reflection and Absorption parameters are investigated to check the resonance response. At each and every point of resonance, highly negative refractive index is been observed. The proposed structure is producing the multiple short as well as large band resonance band over 1 THz to 2.5 THz frequency range for the different chemical potential that varies between 0.1 eV to 0.9 eV. The study results inferred that tunable properties of the GSRR structure can help to design the various photonics device such as sensor, modulator and polarizer, etc.
关键词： Far infrared frequency,Negative refractive index,Graphene split ring resonator,Metamaterial,Tunable
更新于2025-09-12 10:27:22
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[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Visual and Real-Time Biosensor Based on Plasmonic Metamaterials for Biotin-Avidin-System Detection
摘要： Visual real-time plasmonic metamaterial biosensors, relying on surface plasmon resonance (SPR) on metallic subwavelength structures, have significant potential for colorimetric biochemical sensing by simple instrumentation or even naked eye. In this paper, we present a visual and real-time sensing strategy for the detection of the biotin-avidin-system (BAS), which is a powerful tool in biological sciences. The metamaterial, consisting of an array of three-dimensional all-metal nano-cavities, can confine the light into the near field and enable strong light-matter interactions there. Therefore, The metamaterial shows significant color shifts with small refraction index changes. When a monomolecular layer of thiolated biotin and streptavidin bonding to the surface of the nanostructure the successively, metamaterials changes from red to violet and then loden. This sensing strategy offers new opportunities for convenient detection of proteins, nucleic acids and lipids.
关键词： surface plasmon resonance (SPR),BAS detection.,metamaterial
更新于2025-09-12 10:27:22
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Obtaining Directly Quasi-Square Open Ring FSS Constitutive Effective Parameters by Using Coupled WCIP - Retrieval Method
摘要： We propose here a method witch analyze the behavior of Quasi-square open ring frequency selective surface (FSS) by using an approach based on the wave iterative concept procedure method (WCIP) coupled to Retrieval from Scattering Parameters method . The scattering parameters calculated by WCIP for a Quasi-square open ring FSS are used, in analytical formulas, to calculate directly observable effective constitutive parameters (relative electric permittivity εreff , magnetic permeability μreff and refractive index n ) of a frequency selective surface. Results of effective constitutive parameters for a Quasi-square open ring FSS structure are presented by Simulation using MATLAB program codes translating the implementation of the proposed approach.
关键词： WCIP,scattering parameters,metamaterial,retrieval method,FSS,planar structure,effective parameters
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) - Terahertz Polarisation Modulator by Electronic Control of Graphene Loaded Chiral Metamaterial Device
摘要： Terahertz (THz) science and technology has experienced tremendous progress in recent years, such as in spectroscopy, imaging, pharmaceutical research [1] and wireless communications. These applications require electrically tuneable devices to modulate the THz properties, including the amplitude, frequency and polarization. The integration of resonant plasmonic/metamaterial devices with graphene, has proved a successful route for the realisation of fast reconfigurable, efficient THz optoelectronic devices [2], via electrical tuning of graphene integrated with plasmonic resonant structures. An active THz modulator is presented based on a chiral metamaterial array containing metallic features, loaded with graphene. The device makes use of an electromagnetically induced transparency analogue produced via the capacitive coupling of bright and dark resonators, the latter actively damped with graphene, exploited for frequency modulation in Ref. [2]. The active area is 1.2 x 1.2 mm, consisting of a 2D chiral metamaterial array comprising 27 x 27 unit cells, shown in Fig. 1a. The resonators were defined using electron-beam lithography, and thermal evaporation of Ti/Au (10/70nm). These features were deposited on top of a 300 nm insulating layer of SiO2 on a boron p-doped silicon substrate. Chemical vapour deposition grown graphene was defined into 3.25 x 3.25 μm2 patches through e-beam lithography.
关键词： chiral metamaterial,electronic control,graphene,polarisation modulator,Terahertz
更新于2025-09-12 10:27:22
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Modulation of terahertz electromagnetically induced absorption analogue in a hybrid metamaterial/graphene structure
摘要： We proposed a two-layer metamaterial structure with graphene that consists of two H-shaped resonators and one I-shaped resonator. The electromagnetically induced absorption (EIA) analog phenomena were observed in absorption spectra, resulting from the near-field coupling of two bright modes. Furthermore, the absorption peak can be tuned by changing the dimension of the I-shaped resonator or changing the Fermi energy of graphene. The theoretical analysis reveals that the EIA analog arises from magnetic resonance using the coupled Lorentz oscillator model. This hybrid-EIA analog structure may provide a possible choice for designing potential devices for dynamic narrow-band filtering and absorber applications.
关键词： metamaterial,electromagnetically induced absorption,terahertz,dynamic modulation,graphene
更新于2025-09-12 10:27:22
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Triple mode coupling effect and dynamic tuning based on the zipper-type graphene terahertz metamaterial
摘要： We construct a laminated metamaterial structure of zipper-type monolayer graphene with silica which equipped with a distinctively dual plasmon induced transparency (PIT) phenomenon. The graphene pattern in this structure crafty connects with the electrode so that we can dynamically control the PIT response (via regulating the bias voltage that applied between the electrode and the substrate to control the graphene Fermi energy). In which, the range of voltage-regulate is calculated theoretically that proved to be a feasible measure for PIT response-tune. Then, the tuning discipline for this structure is summarized from the calculated result of coupled mode theory (CMT) deduced theoretical model and the simulation result. It is found that the structure possesses a great tuning performance within the tuning range we studied; also, such the structure ameliorates the monolayer graphene absorbance from 2.3% to about 50% within a broad dynamic frequency tuning range, the absorption peak frequency modulation depth is up to 45.46%. Besides, the group refractive index is discussed for reflecting the system capability of slow light, and the maximum of the coefficient can catch up to 595. Even if the impact of dielectric light- absorbance to slow light is taken into account, the slow light index at the transparent window is still as high as 200.
关键词： Absorbance,Plasmon induced transparency,Dynamic tuning,Slow light device,Graphene metamaterial
更新于2025-09-12 10:27:22
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A Dual-Band Terahertz Absorber with Two Passbands Based on Periodic Patterned Graphene
摘要： In this paper, a dual-band terahertz absorber with two passbands is proposed. The absorber is composed of periodic patterned graphene arrays on the top of a SiO2 substrate and a frequency selective surface (FSS) on the bottom of the substrate. The simulated results indicate that there are two absorption bands (absorption greater than 90%) ranging from 0.54 to 0.84 THz and 2.13 to 2.29 THz. It is almost transparent to incident waves (transmission greater than 50%) below 0.19 THz and between 1.3 and 1.67 THz with a center frequency of 1.49 THz. The absorber has a good tolerance to the transverse electric (TE) and transverse magnetic (TM) polarized wave oblique incidence, and the transmission rate of the passbands remains greater than 50% within 70 degrees. Moreover, the absorption rate of the absorber can be tuned by the chemical potential of graphene. The structure with absorption and transmission properties has potential applications in filtering, sensing, detecting and antenna stealth.
关键词： passband,graphene,metamaterial absorber
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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Plasmonic interference lithography by coupling the bulk plasmon polariton mode and the waveguide mode
摘要： Plasmonic lithography based on surface plasmon polariton has been proven to breaking the diffraction limit and deliver the super-resolution patterns. However, most previously reported studies suffer from the low energy efficiency and subwavelength excitation grating which obstruct the application in nanofabrication. In this work, a special plasmonic lithography prototype is proposed based on the coupling of the bulk plasmon polariton (BPP) mode squeezed through the hyperbolic metamaterial (HMM) and the waveguide mode supported in the Coupling layer/HMM/PR (photoresist) sandwich structure. The results demonstrate that periodic patterns with strong lithography light intensity (>220%) over the whole photoresist layer compared with incident optical intensity, high aspect ratios (1.5:1) and a half-pitch of 57.5 nm can be generated, under the interference of the fourth-order diffracted light of grating. The lithography linewidth can reach 1/16 of the mask period of 920 nm and ~1/8 of the wavelength of the 436nm illumination light. This design of period reduction makes the device fabrication much easy, costless and even exhibits good tolerant to the roughness of the multilayer. In addition, theoretical analyses performed are widely applicable to systems working at other ultraviolet wavelengths including 248, 365 and 405 nm.
关键词： hyperbolic metamaterial,bulk plasmon polariton,waveguide mode,plasmonic lithography,surface plasmon
更新于2025-09-12 10:27:22