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- 摘要
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- 实验方案
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Coupling a silicon-on-insulator waveguide to a metala??dielectrica??metal plasmonic waveguide through a vertical and lateral taper-funnel structure
摘要： Designing efficient and compact couplers is crucial in hybrid integration of plasmonic components with conventional silicon-on-insulator components. Taper-funnel structures are conventionally used to couple light from a silicon strip waveguide to a metal–dielectric–metal plasmonic waveguide. In this paper, we investigate the effect of different parameters of the metallic funnel and the vertically and laterally tapered silicon waveguide on the performance of the designed coupler. Numerical simulations indicate that the tuned coupler has an average coupling efficiency of 87% in the C-band. The designed 1.18-μm-long coupler has a shorter length compared to the previous designs, while its theoretical coupling efficiency is higher than 85% in the entire O, E, S, C, L, and U bands of optical communication.
关键词： silicon-on-insulator,plasmonic waveguide,taper-funnel structure,coupling efficiency
更新于2025-09-23 15:21:01
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Surface-polaritonic phase singularities and multimode polaritonic frequency combs via dark rogue-wave excitation in hybrid plasmonic waveguide
摘要： Material characteristics and input-?eld speci?cs limit controllability of nonlinear electromagnetic-?eld interactions. As these nonlinear interactions could be exploited to create strongly localized bright and dark waves, such as nonlinear surface polaritons, ameliorating this limitation is important. We present our approach to amelioration, which is based on a surface-polaritonic waveguide recon?guration that enables excitation, propagation and coherent control of coupled dark rogue waves having orthogonal polarizations. Our control mechanism is achieved by ?nely tuning laser-?eld intensities and their respective detuning at the interface between the atomic medium and the metamaterial layer. In particular, we utilize controllable electromagnetically induced transparency windows commensurate with surface-polaritonic polarization-modulation instability to create symmetric and asymmetric polaritonic frequency combs associated with dark localized waves. Our method takes advantage of an atomic self-defocusing nonlinearity and dark rogue-wave propagation to obtain a suf?cient condition for generating phase singularities. Underpinning this method is our theory which incorporates dissipation and dispersion due to the atomic medium being coupled to nonlinear surface-polaritonic waves. Consequently, our waveguide con?guration acts as a bimodal polaritonic frequency-comb generator and high-speed phase rotator, thereby opening prospects for phase singularities in nanophotonic and quantum communication devices.
关键词： rogue wave,surface plasmon polariton,frequency comb,plasmonic waveguide,electromagnetically induced transparency
更新于2025-09-23 15:21:01
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Modal characteristics of refractive index engineered hybrid plasmonic waveguide
摘要： In this work, we proposed a novel design of a refractive index engineered subwavelength grating silicon-based hybrid plasmonic waveguide via the finite element method. The intensity integral (Γ) in the upper cladding can be controlled by varying the thickness (HSi) of the top silicon layer. The highest evanescent field ratio of 0.85 is obtained at HSi=200 nm which allows the hybrid mode to confine in the low index medium and a large evanescent field resides in the upper cladding. The sensitivity of the waveguide is calculated by monitoring the change in the effective refractive index to the ambient refractive index. The maximum mode sensitivity of 0.7 is obtained. The spectral performance of the subwavelength grating (SWG) hybrid plasmonic waveguide (HPWG) based ring resonator design is studied which exhibits a sensitivity as high as 1000 nm/RIU which is higher than the previously reported values. We believe that the proposed waveguide scheme is an ideal candidate to produce highly sensitive lab-on-chip sensors.
关键词： microring resonator,refractive index sensor,Subwavelength grating hybrid plasmonic waveguide,Evanescent field ratio
更新于2025-09-23 15:21:01
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Extension of an FFT-Based Beam Propagation Method to Plasmonic and Dielectric Waveguide Discontinuities and Junctions
摘要： We adapted a fast Fourier transform-based Beam Propagation Method (FFT-BPM) to investigate waveguide discontinuities in plasmonic waveguides. The adaptation of the FFT-BPM to treat transverse magnetic (TM) fields requires the circumvention of two major difficulties: the mixed derivatives of the magnetic field and waveguide refractive index profile in the TM wave equation and the step-like index change at the transverse metal-dielectric boundary of the plasmonic guide and the transverse boundaries of the dielectric waveguide as well. An equivalent-index method is adopted to transform TM fields to transverse electric (TE) ones, thus enabling the benefit of the full power and simplicity of the FFT-BPM. Moreover, an appropriate smoothing function is used to approximate the step-like refractive index profile in the transverse direction. At the junction plane, we used an accurate combined spatial-spectral reflection operator to calculate the reflected field. To validate our proposed scheme, we investigated the modal propagation in a silicon waveguide terminated by air (like a laser facet in two cases: with and without a coating layer). Then we considered a subwavelength plasmonic waveguide (metal-insulator-metal MIM) butt-coupled with a dielectric waveguide, where the power transmission efficiency has been calculated and compared with other numerical methods. The comparison reveals good agreement.
关键词： butt-coupler,plasmonics,FFT-BPM,sensors,plasmonic waveguide,bi-directional BPM,photonics,reflection formalism,TM fields,optical propagation
更新于2025-09-23 15:19:57
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Terahertz shifted Fano resonance-induced plasmon-soliton in graphene-plasmonic waveguide with magnetic impurities
摘要： Fano resonance is a quantum effect particularly useful for determining the optical spectra of semiconductor heterostructures and radiation enhancement of semiconductor-based devices. We deal with the nonlinear amplitude equation to find the nonlinear plasmon modes and breather solutions in a magnetic impurities-added graphene-plasmonic waveguide at near and mid-IR frequency range. The results show that the coupling degree between the plamon modes and breather solutions in order to form plasmon-solitons is intensely influenced by the effective nonlinear refraction assigned to the waveguide and also by the Fermi energy; tunable plasmon-solitons can be formed with a lowly required bias voltage. We also deduce that the stable plasmon-solitons and subsequently the most condensed radiative feature with the largest effective propagation length can be obtained at interband transition edge if the resonance of the effective nonlinear refraction is of Fano type. The reason is inferred as the presence of a reversible mechanism caused by the optical doping which in turn bears a successive competition between the diffraction and nonlinearity. Accordingly, we indicate that the Fano resonance- induced plasmon-soliton modes supported by the Co-added graphene-plasmonic waveguide experience a frequency shift up to Δω ? 60 THz in contrast to the plasmon-soliton modes in the pristine graphene-based waveguide. This in turn, proposes a novel technique for the spectroscopy of magnetic impurities-added graphene-dielectric heterostructures. On the other hand, very sensi- tive modulation of the nonlinear response tunable with a low Fermi energy as presented in this study can delineate modern schemes for the next generation graphene plasmonic devices including the nanoscale radiation sources, modulators, biosensors and couplers.
关键词： Fano resonance,Graphene plasmonic waveguide,Plasmon-soliton,Nonlinear refraction,Breather solution,Magnetic impurities
更新于2025-09-23 15:19:57
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Tailoring the plasmonic Fano resonance in metallic photonic crystals
摘要： Periodically arranged metallic nanowires on top of a waveguide layer show a strong coupling between the particle plasmon of the wires and the waveguide mode. By introducing a dielectric spacer layer between the metallic structures and the waveguide layer, this coupling can be reduced. Here, the thickness of this spacer layer is varied and the coupling strength is determined for each spacer layer thickness by fitting an effective energy matrix to the energy positions of the resonance peaks. It is found that the coupling strength can be very well described by the electric field amplitude of the waveguide mode at the location of the nanowires. We carried out experiments and found very good agreement with theory and our simple model. Using this method, we achieved experimentally an extremely small mode splitting as small as 25 meV leading to very sharp spectral features. Our pathway and design for tailoring the coupling strength of plasmonic Fano resonances will enable the design of highly sensitive plasmonic sensor devices and open the door for narrow plasmonic spectral features for nonlinear optics and slow light propagation.
关键词： photonic crystals,coupling strength,Fano resonance,plasmonic,waveguide
更新于2025-09-23 15:19:57
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A Graphene based bimetallic plasmonic waveguide to increase photorefractive effect
摘要： In this paper, for enhancement of the nonlinear optical properties of photorefractive gain, a novel plasmonic waveguide is proposed. The geometry of the proposed structure is optimized to reach the highest photorefractive gain. The proposed structure is based on bimetallic structure and it includes a graphene layer. It is shown that a strong mode can be coupled to a weak mode by means of photorefractive effect. It is found that comparing with the conventional symmetric and asymmetric metal-insulator-metal plasmonic waveguides, the proposed structure with different metals and a graphene layer with an optimized notch has higher photorefractive gain and longer propagation distance, the distance for which a net photorefractive gain exists. The effect of the crystal thickness and amplitude inputs are also analyzed. It is found that there is an optimum crystal thickness that yields the maximum photorefractive gain.
关键词： asymmetric structure,Photorefractive e?ect,graphene,plasmonic waveguide,photorefractive gain
更新于2025-09-23 15:19:57
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Tunable plasmon-induced transparency and slow light in terahertz chipscale semiconductor plasmonic waveguides
摘要： We numerically propose the plasmon-induced transparency (PIT) and slow light effect based on terahertz (THz) chipscale plasmonic semiconductor-insulator-semiconductor (SIS) waveguide system. Via the coupling between two stub resonators, PIT is introduced due to the destructive interference, which can be theoretically described by the transmission-line Method (TLM). Meanwhile, the strong dispersion within the transparent window will lead to the slow light effect. Via tuning the geometric parameters, the profile of PIT as well as group delay line can be arbitrarily tailored. Moreover, active control of both PIT and slow light can be realized by changing the ambient temperature. Especially, by integrating monolayer graphene into the structure, PIT and slow light can also be electrically modulated via applying voltage. This work provides geometrical, thermal and electrical approaches to manipulate THz transmission and group delay in subwavelength scale, and can find potential applications as filters, sensors, modulators and active optical delay lines in THz ultracompact circuits.
关键词： graphene,plasmon-induced transparency,slow light,terahertz,plasmonic waveguide
更新于2025-09-23 15:19:57
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Hybrid plasmonic waveguide coupling of photons from a single molecule
摘要： We demonstrate the emission of photons from a single molecule into a hybrid gap plasmon waveguide. Crystals of anthracene, doped with dibenzoterrylene (DBT), are grown on top of the waveguides. We investigate a single DBT molecule coupled to the plasmonic region of one of the guides and determine its in-plane orientation, excited state lifetime, and saturation intensity. The molecule emits light into the guide, which is remotely out-coupled by a grating. The second-order autocorrelation and cross-correlation functions show that the emitter is a single molecule and that the light emerging from the grating comes from that molecule. The coupling efficiency is found to be βWG = 11.6(1.5)%. This type of structure is promising for building new functionality into quantum-photonic circuits, where localized regions of strong emitter-guide coupling can be interconnected by low-loss dielectric guides.
关键词： single molecule,photon emission,hybrid plasmonic waveguide,quantum-photonic circuits
更新于2025-09-19 17:13:59
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Raman scattering and self-steepening in nonlinear plasmonic waveguide pulse equation
摘要： In this paper, we use Maxwell equations and the first order perturbation theory to obtain pulse propagation equation in a plasmonic waveguide made of nonlinear dielectric material. In this study, the effects of nonlinear self-steepening and Raman scattering are considered. Nonlinear coefficients of phase modulation, Raman and self-steepening are calculated numerically in terms of frequency and compared with a standard silica fiber. Obtained values of the nonlinear coefficients are about up to 300 times larger than that of standard silica optical fibers. So they can be used as part of all optical integrated circuit such as continuum generation, optical switching and frequency conversion.
关键词： Nonlinear optics,Self-steepening,Raman scattering,Nonlinear plasmonic waveguide
更新于2025-09-19 17:13:59