- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Control of Charge Carrier Dynamics in Plasmonic Au Films by TiO <sub/><i>x</i> </sub> Substrate Stoichiometry
摘要： Plasmonic excitations in noble metals have many fascinating properties and give rise to a broad range of applications. We demonstrate, using non-adiabatic molecular dynamics combined with time-domain density functional theory, that chemical composition and stoichiometry of substrates can have a strong influence on charge dynamics. By changing oxygen content in TiO2, including stoichiometric, oxygen rich and oxygen poor phases, and Ti metal, one can alter lifetimes of charge carriers in Au by a factor of 5, and control the ratio of electron-to-hole relaxation rates by a factor of 10. Remarkably, a thin TiOx substrate alters so much charge carrier properties in much thicker Au films. Such large variations stem from the fact that the Ti and O atoms are much lighter than Au, and their vibrations are much faster at dissipating the energy. The control over a particular charge carrier and an energy range depends on the Au and TiOx level alignment, and the interfacial interaction strength. These factors are easily influenced by the TiOx stoichiometry. In particular, oxygen rich and poor TiO2 can be used to control holes and electrons, respectively, while metallic Ti affects both charge carriers. The detailed atomistic analysis of the interfacial and electron-vibrational interactions generates the fundamental understanding of the properties of plasmonic materials needed to design photovoltaic, photocatalytic, optoelectronic, sensing, nanomedical and other devices.
关键词： non-adiabatic molecular dynamics,substrate layers,time-domain density functional theory,metallic films,electron-phonon energy relaxation,surface plasmons
更新于2025-09-19 17:13:59
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?± spiral nanoslit and the higher order plasmonic vortex generation
摘要： In view of the conciseness of a spiral nanoslit and the limited order of the generated vortex, a kind of nanometer spirals named α spirals are proposed to generate the higher order plasmonic vortex. Theoretical analysis provides the basis for the advancement of α spiral. The proposed spiral can generate the plasmonic vortex and the extreme order of the generated vortex depends on the parameter α. The numerical simulations definite the valid region of the plasmonic vortex generated by the α spiral. Discussions about the validity range of the α spiral nanoslit and the influence of the film material are beneficial to generate the high order vortex. This work builds a platform for the generation of the higher order plasmonic vortex using the simple spiral nanostructure and it can extend the potential applications of higher order plasmonic vortices.
关键词： Theory and design,Plasmonic vortex,Nanostructure,Surface Plasmons
更新于2025-09-19 17:13:59
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Surface-plasmon-enhanced LED based on multilayer gratings and core-shell Ag/SiO <sub/>2</sub> nanoparticles
摘要： This paper proposes a novel GaN-based LED with nano-grating structure based on surface plasmons. This structure mainly contains n-GaN, multiple quantum wells and p-GaN, Ag–SiO2 grating, core–shell Ag/SiO2 nanoparticle and ITO triangular grating. The basic principle of the light emitting characteristics of LED is described in detail. The COMSOL software is used to analyse properties and optimise parameters based on the ?nite element method. The radiated intensity, absorbed intensity and electric ?eld distribution are obtained. The results indicate that this structure has a higher luminous ef?ciency with the luminous intensity increased to about 58.59 times compared with the ordinary structure and about 3.94 times compared with the reference structure, and can enhance the internal quantum ef?ciency and the external quantum ef?ciency of the LED simultaneously.
关键词： light-emitting diode,quantum wells,grating,surface plasmons
更新于2025-09-19 17:13:59
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Plasma and Plasmonics || 6 Spoof Surface Plasmons (SSP)
摘要： In the previous chapter, we studied the properties of surface plasmons on a planar metal-dielectric interface and found that for these waves to exist, the permittivity of the dielectric and metal must be of opposite signs. This condition is satisfied at frequencies slightly below the metal plasma frequency, since in this frequency range, the permittivity of the metal is given by ?/?0 = 1 ? ω2p/ω2. These surface plasmon waves are characterized by three quantities: β, k1, k2. β is the propagation constant along the interface, k1 is the decay constant in the dielectric medium and k2 is the decay constant in the metallic region. These quantities depend on the permittivities and frequency through these relations (Eqs. (5.24) and (5.26)).
关键词： metal-dielectric interface,permittivity,Spoof Surface Plasmons,plasma frequency,SSP,surface plasmons
更新于2025-09-16 10:30:52
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Graphene Photonics || Plasmonics
摘要： Graphene has unique plasmonic properties because of its unusual electromagnetic properties and its 2D geometric structure. Graphene supports plasma oscillations when it has a nonzero chemical potential. Different from a metal, which has a fixed carrier density, thus a fixed plasma frequency, graphene is similar to a semiconductor in that its carrier density, thus its plasma frequency, can be varied by varying its chemical potential through, for example, impurity doping, electrical modulation, or optical illumination. Nevertheless, graphene is very different from an ordinary semiconductor because of its unique band structure and its 2D geometry. As a 2D material, graphene naturally supports true surface plasmons and, in a certain spectral region depending on its chemical potential, surface plasmon polaritons. As discussed in preceding chapters, the electromagnetic properties of graphene approach those of a conductor at low frequencies and those of a dielectric at optical frequencies. Between the two limits, particularly in the terahertz frequency region, graphene has sophisticated electromagnetic properties that can be tuned through varying its chemical potential. For this reason, graphene has very interesting plasmonic properties that lead to many useful applications in the terahertz region.
关键词： Surface Plasmons,Plasmonics,Graphene,Surface Plasmon Polaritons,Terahertz
更新于2025-09-16 10:30:52
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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) - Amplifying SP-Enhanced SHG with NLO Polymers Grown on Ag Films
摘要： Nonlinear plasmonics is one of the most fundmental applications of intense and confined optical fields due to surface plasmons. The technology will be vital for building next-generation ultra-compact and ultrafast optical signal processing and telecommunication systems. Most of the previous studies have been challenged by taking advantages of surface nonlinearities of the metals, where the surface plasmons (SPs) are generated. Here, we will present amplified nonlinear operations due to NLO active polymer layers grown on the metal surfaces.
关键词： Nonlinear plasmonics,surface plasmons,NLO polymers,SHG spectroscopy
更新于2025-09-16 10:30:52
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Ultralow-Power Electrically Activated Lab-on-a-Chip Plasmonic Tweezers
摘要： We propose ultralow-power plasmonic tweezers with no external optical source. They consist of a one-dimensional array of graphene-based plasmonic units driven by the optical transitions within the underlying array of (Al, In)As/(Ga, In)As/(Al, In)As/(Ga, In)As/(Al, In)As quantum cascaded heterostructures (QCHs), electrically biased in series. Each QCH unit formed in a nanopillar can act as a built-in optical source required for exciting the localized surface plasmons (LSPs) at the surface of the overlying circular graphene nanodisk. The stimulated emission due to intersubband transition within each optical source evanesces through the top (Al, In)As cladding layer and interacts with the overlying graphene nanodisk, inducing the LSPs required for the formation of the plasmonic tweezers. Numerical simulations show, under 145–170 mV applied voltages, that the tweezers with graphene nanodisks of 16–30 nm in diameter and chemical potentials of 0.5–0.7 eV can trap polystyrene nanoparticles of 9 nm in diameter and larger, demonstrating acceptable sensitivities for variations in the nanoparticle diameter and refractive index. These lab-on-a-chip plasmonic tweezers, bene?ting from their small footprints and ultralow power consumptions, which are capable of sensing and trapping nanoparticles without requiring expensive external optical sources, open up a di?erent horizon for developing compact on-chip plasmonic tweezers.
关键词： plasmonic tweezers,localized surface plasmons,graphene,lab-on-a-chip,quantum cascade heterostructures
更新于2025-09-16 10:30:52
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Plasmonic nanoslit-based dual-wavelength multiplexer
摘要： A novel plasmonic dual-wavelength multiplexer to couple free-space waves to metal–insulator–metal (MIM) waveguides is proposed, designed and simulated. The proposed structure is based on two nanoslits carved on a metal film. Through an appropriate spacing between the nanoslits, it is possible to design this structure to couple two different wavelengths onto MIM modes such that they propagate in the same direction. The designed structure is simulated using FEM technique, and results for circular and plane wave fronts are demonstrated. High extinction ratio of greater than 10 dB is obtained in all the cases.
关键词： Unidirectional couplers,Extinction ratio,Plasmonic multiplexer,Metal–insulator–metal waveguide,Surface plasmons
更新于2025-09-16 10:30:52
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Plasmonic Metamaterials for Nanochemistry and Sensing
摘要： Plasmonic nanostructures were initially developed for sensing and nanophotonic applications but, recently, have shown great promise in chemistry, optoelectronics, and nonlinear optics. While smooth plasmonic films, supporting surface plasmon polaritons, and individual nanostructures, featuring localized surface plasmons, are easy to fabricate and use, the assemblies of nanostructures in optical antennas and metamaterials provide many additional advantages related to the engineering of the mode structure (and thus, optical resonances in the given spectral range), field enhancement, and local density of optical states required to control electronic and photonic interactions. Focusing on two of the many applications of plasmonic metamaterials, in this Account, we review our work on the sensing and nanochemistry applications of metamaterials based on the assemblies of plasmonic nanorods under optical, as well as electronic interrogation.
关键词： field enhancement,sensing,localized surface plasmons,optical antennas,nanochemistry,optical resonances,electronic interrogation,surface plasmon polaritons,metamaterials,Plasmonic nanostructures
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Multilayer optical routing by means of vertical directional coupler with long range surface plasmons
摘要： We show that e?cient multilayer optical routing is achievable with long range surface plasmon polaritons (LR-SPP) through an accurate design of vertical directional couplers (VDC). Our theoretical results suggest that by suitably tuning some geometrical parameters, in particular the path length and bend radius, it is possible to obtain a good control on the overall interaction, even in presence of fabrication non-idealities. We present a top-down fabrication process ?ow for LR-SPP multilayer optical circuits, obtained by stacking multiple ultrathin nanometric metal ?lms within a polymeric dielectric background; the overall structure has a good degree of mechanical stability. By pro?ting from the topological advantage given by VDCs, as one of the useful applications of our work, we propose a new optical integrated circuit architecture scheme, capable of connecting two separate circuit paths without in?uencing the geometry or signi?cantly promoting crosstalk with any other path in the middle. The possibility to develop vertically stacked optical integrated circuits upon electronic integrated circuits makes LR-SPPs a good technology for the production of inexpensive and high-density network systems.
关键词： optical integrated circuits,long range surface plasmons,multilayer optical routing,vertical directional coupler
更新于2025-09-12 10:27:22