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[IEEE 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) - Seoul, Korea (South) (2019.1.27-2019.1.31)] 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) - All-Metal Plasmonic Metamaterials for Structure Color and as Colorimetric Biosensors
摘要： Colorimetric and label-free plasmonic biosensors, relying on localized surface plasmon resonance (LSPR) on metallic subwavelength structures, have significant potential for many application areas such as clinical diagnosis and environmental monitoring detection by simple instrumentation or even naked eye. In this paper, we present a high-performance colorimetric and label-free plasmonic biosensors, consisting of an array of three-dimensional all-metal nano-cavities. The nanostructures, composed of a top array of gold disk, aluminum pillar and bottom gold reflection film, are similar to metal-insulator-metal and the insulating layer is air cavities that are easy to be filled with other gaseous or liquid dielectric. Therefore, the analytes could permeate into the nano-scale cavities and enable strong light-matter interactions there. The sensor shows significant color difference with small refraction index changes and the sensitivity reaches 683.5 nm/RIU. Moreover, when a monomolecular layer of Dithiobis(succinimidyl propionate) (DSP) was bonded to the surface of the nanostructure, the color of the metamaterials change from blue to green back. The metamaterials will offer great potential for detection and studies of binding events between the target analyte and its corresponding receptor.
关键词： LSPR,label-free,metamaterials,colorimetric,plasmonic biosensors
更新于2025-09-12 10:27:22
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Controlled generation of chimera states in SQUID metasurfaces using DC flux gradients
摘要： SQUID (Superconducting QUantum Interference Device) metasurfaces, subject to a time-independent (dc) flux gradient and driven by a sinusoidal (ac) flux field, support chimera states that can be generated with zero initial conditions. The dc flux gradient and the amplitude of the ac flux can thus control the number of desynchronized clusters of such a generated chimera state (i.e., its “heads”) as well as their location and size. The combination of three measures, i.e., the synchronization parameter averaged over the period of the driving flux, the strength of incoherence, and the discontinuity measure, is used to predict the emergence or not of a chimera state and its multiplicity on the parameter plane of the dc flux gradient and the ac flux amplitude. Moreover, the full-width half-maximum of the distribution of the values of the synchronization parameter averaged over the period of the ac driving flux, allows to distinguish chimera states from non-chimera, partially synchronized states. Our findings are relevant from the pointview of both theory and applications. The SQUID oscillator provides an excellent physical example of systems with inertia and driving, for which chimera states have been under-examined. Finally, in the parameter regime under consideration, SQUID lattices are systems which are experimentally realisable and have very important applications in metamaterials science.
关键词： Flux gradient,SQUID Metasurfaces,Chimera states,Superconducting metamaterials
更新于2025-09-12 10:27:22
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[ACM Press the Sixth Annual ACM International Conference - Dublin, Ireland (2019.09.25-2019.09.27)] Proceedings of the Sixth Annual ACM International Conference on Nanoscale Computing and Communication - NANOCOM '19 - Graphene epsilon-near-zero plasmonic crystals
摘要： Plasmonic crystals are a class of optical metamaterials that consist of engineered structures at the sub-wavelength scale. They exhibit optical properties that are not found under normal circumstances in nature, such as negative-refractive-index and epsilon-near-zero (ENZ) behavior. Graphene-based plasmonic crystals present linear, elliptical, or hyperbolic dispersion relations that exhibit ENZ behavior, normal or negative-index diffraction. The optical properties can be dynamically tuned by controlling the operating frequency and the doping level of graphene. We propose a construction approach to expand the frequency range of the ENZ behavior. We demonstrate how the combination of a host material with an optical Lorentzian response in combination with a graphene conductivity that follows a Drude model leads to an ENZ condition spanning a large frequency range.
关键词： plasmonics,photonics,metamaterials,Graphene,photonic crystal
更新于2025-09-12 10:27:22
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Vertical growth of plasmonic nanostructures via electrodeposition on a conductive oxide
摘要： Metallic nanostructures have a variety of interesting properties and applications, especially as substrates for LSPR-based refractometric sensors for biological and chemical species. A common method for metal deposition is electron beam evaporation. However, this is limited to structures with heights on the order of tens of nanometers. Growth of tall structures for such sensors provides greater surface area for binding and increased interaction volume. Methods for creating taller structures are limited, with the most common method being electrodeposition. This is typically done on a nonconductive substrate by using a seed a layer of the metal to be grown, optionally with a thin adhesion layer using a metal such as chromium. In this work, we propose elimination of the need for a seed layer and its subsequent removal by directly electrodepositing onto a transparent conductive substrate suitable for plasmonic applications.
关键词： Electrodeposition,Sensors,Plasmonics,Metamaterials
更新于2025-09-12 10:27:22
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Active control on switchable waveguide of elastic wave metamaterials with the 3D printing technology
摘要： Propagation of elastic waves along a direction has special interests in practical applications. These concerns generate the design of an elastic wave metamaterial with electrically switchable properties, which is studied in this work. The structure contains a T-shaped waveguide in a plate with the 3D printing technology; and the active control system is used to tune the propagation direction of the flexural wave. The piezoelectric patches which are connected by the negative capacitance circuits are applied to behave as the active control system. The finite element simulation is performed to give the theoretical prediction of the switchable waveguide and the tunable equivalent parameters are achieved by the electrical circuits. The active control experiments are finally carried out to support the numerical design.
关键词： 3D printing technology,switchable waveguide,elastic wave metamaterials,negative capacitance circuits,active control,piezoelectric patches
更新于2025-09-12 10:27:22
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Arrays of Plasmonic Nanoparticle Dimers with Defined Nanogap Spacers
摘要： Plasmonic molecules are building blocks of metallic nanostructures that give rise to intriguing optical phenomena with similarities to those seen in molecular systems. The ability to design plasmonic hybrid structures and molecules with nanometric resolution would enable applications in optical metamaterials and sensing that presently cannot be demonstrated, because of a lack of suitable fabrication methods allowing the structural control of the plasmonic atoms on a large scale. Here we demonstrate a wafer-scale ‘lithography-free’ parallel fabrication scheme to realize nanogap plasmonic meta-molecules with precise control over their size, shape, material, and orientation. We demonstrate how we can tune the corresponding coupled resonances through the entire visible spectrum. Our fabrication method, based on glancing angle physical vapor deposition with gradient shadowing, permits critical parameters to be varied across the wafer and thus is ideally suited to screen potential structures. We obtain billions of aligned dimer structures with controlled variation of the spectral properties across the wafer. We spectroscopically map the plasmonic resonances of gold dimer structures and show that they are not only in a good agreement with numerically modeled spectra, but also remain functional, at least for a year, in an ambient condition.
关键词： glancing angle deposition,wafer-scale nanofabrication,asymmetric shadow,nanophotonics,optical metamaterials,scalable plasmonics
更新于2025-09-12 10:27:22
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Coupling Between Silicon Waveguide and Metal-Dielectric-Metal Plasmonic Waveguide with Lens-Funnel Structure
摘要： Various photonic integrated components have been implemented by ultra-thin silicon-on-insulator (SOI) waveguides; therefore, it is desirable to couple ultra-thin SOI waveguides to plasmonic waveguides. In this paper, we present an ultra-thin SOI waveguide to a metal-dielectric-metal plasmonic waveguide based on a lens-funnel structure consisting of truncated Luneburg lens and metallic parabolic funnel. The lens is implemented by varying the guiding layer thickness. The effect of different parameters of the coupler’s geometry is studied using the finite-difference time-domain method. The 1.13-μm-long coupler improves the average coupling efficiency in the C-band from 66.4 to 82.1%. The numerical simulations indicate that the coupling efficiency is higher than 69% in the entire O, E, S, C, L, and U bands of optical communication.
关键词： Luneburg lens,Silicon-on-insulator,All-dielectric metamaterials,Plasmonic waveguide,Optical coupler,Strip waveguide
更新于2025-09-12 10:27:22
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Efficient Finite Element Analysis of Axially Symmetrical Waveguides and Waveguide Discontinuities
摘要： A combination of the body-of-revolution and finite element methods is adopted for full-wave analysis of waveguides and waveguide discontinuities involving angular field variation. Such an approach is highly efficient and much more flexible than analytical techniques. The method is performed in two different cases: utilizing a generalized impedance matrix to determine the scattering parameters of a single waveguide section and utilizing periodic boundary conditions without sources. In order to confirm the validity and efficiency of both approaches, a few examples of axially symmetrical structures have been analyzed. The obtained results are compared to those obtained from commercial software and available in the literature.
关键词： generalized impedance matrix (GIM),periodic boundary conditions (PBCs),dispersion diagrams,metamaterials,Cylindrical waveguides,finite element method (FEM)
更新于2025-09-12 10:27:22
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Dispersion of THz Modes Localized on Layered Superconductor Controlled by DC Magnetic Field
摘要： Being materials that support terahertz waves propagation, layered superconductors attract great attention of many researchers. The Josephson plasma modes localized on a slab of layered superconductor can possess an anomalous dispersion. The possibility of anomalous dispersion manipulation opens wide perspectives for applications. One of the tools that can flexibly change the electromagnetic properties of layered superconductors is the external DC magnetic field. The effect of the DC magnetic field on the spectrum of the localized modes is a subject of the present paper. We present the derivation and analysis of the dispersion relations and discuss some interesting corollaries such as resonant amplification of wave transmission induced by the internal excitation of the localized modes and the possibility of the internal reflection of the localized modes controlled by the external DC magnetic field.
关键词： high-temperature superconductors,electromagnetic fields,Terahertz metamaterials,Josephson junctions
更新于2025-09-12 10:27:22
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Donor–Acceptor Distance-Dependent Charge Transfer Dynamics Controlled by Metamaterial Structures
摘要： Capability to control charge transfer dynamics in donor-acceptor molecule is important for efficient optoelectronic devices. Charge transfer dynamics is governed by thermodynamics of donor-acceptor charges in a given dielectric environment. Metamaterial structure has been shown to be able to control charge separation and charge recombination processes via nonlocal effect on dielectric permittivity for a fixed donor-acceptor distance organic film. Here, we report the influence of metamaterial structure on the donor-acceptor distance dependence of electron transfer process occurring in liquid crystalline organic semiconductor thin films. By examining charge recombination rate in three different donor-acceptor distances, it is found that the barrier height β increases from 0.084 ??1 to 0.137 ??1 by 63% in the presence of metal-dielectric multilayered metamaterial structures. Based on Marcus theory on charge transfer process, we show that the further increase of driving force for a larger donor-acceptor distance is mainly responsible for the barrier height increase in the presence of multi-layered metamaterial substrate when compared with glass substrate. This study will provide a significant step forward in enabling more efficient hybrid organic-optoelectronic devices associated with charge transfer process.
关键词： Charge transfer dynamics,Organic semiconductors,Metamaterials,Marcus Theory,Nonlocal effect
更新于2025-09-12 10:27:22