- 标题
- 摘要
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- 实验方案
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Deep ultraviolet tip-enhanced fluorescence
摘要： Theoretical calculations were performed for the deep ultraviolet (DUV) tip-enhanced ?uorescence (TEF) using Al@Al2O3 core–shell tips. Fluorescence enhancement, spatial resolution and surface plasmon coupled emission (SPCE) of DUV-TEF were quantitatively studied by ?nite-difference time-domain (FDTD) method. FDTD results demonstrate that the enhancement factor (EF) of TEF can be as high as 3 orders of magnitudes in the optimal TEF geometry. At the DUV excitation wavelength of 244 nm, the spatial resolution and SPCE angles are 6 nm and ±23°, respectively, showing maximum EF of 7.4×102. Our results not only help understanding the underlying physical mechanism for developing high-sensitivity and high-resolution DUV-TEF platform, but also contribute to expanding TEF technology from visible to UV range.
关键词： ?uoresence,plasmon,deep ultraviolet
更新于2025-09-09 09:28:46
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Surface plasmon polariton at the interface of dielectric and graphene medium using Kerr effect
摘要： We theoretically investigate the control of surface plasmon polariton (SPP) generated at the interface of dielectric and graphene medium under Kerr nonlinearity. The controlled Kerr nonlinear signal of probe light beam in a dielectric medium is used to generate SPPs at the interface of dielectric and graphene medium. The positive, negative absorption, and dispersion properties of SPPs are modi?ed and controlled by the control and Kerr ?elds. A large ampli?cation (negative absorption) is noted for SPPs under the Kerr nonlinearity. The normal/anomalous slope of dispersion and propagation length of SPPs is modi?ed and controlled with Kerr nonlinearity. This leads to signi?cant variation in slow and fast SPP propagation. The controlled slow and fast SPP propagation may predict signi?cant applications in nano-photonics, optical tweezers, photovoltaic devices, plasmonster, and sensing technology.
关键词： Kerr nonlinearity,surface plasmon polariton,graphene
更新于2025-09-09 09:28:46
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Subwavelength asymmetric Au–VO <sub/>2</sub> nanodisk dimer for switchable directional scattering
摘要： We propose an asymmetric Au–VO2 nanodisk dimer for realizing a switchable directional scattering. Specifically, the directional scattering can be triggered on/off through controlling the phase transition of the VO2 nanodisk from metallic to semiconductor state. More strikingly, an obvious directional scattering with the directivity of ～ 40 dB is achieved under the metallic state of VO2 nanodisk. This tunable directional scattering is further explained with an interference model where the Au and VO2 nanodisks are treated as two weakly interacting electric dipoles. The phase transition controlled scattering patterns of asymmetric Au–VO2 nanodisk dimer are then well interpreted from the phase difference between these two dipoles.
关键词： directional scattering,vanadium dioxide,localized surface plasmon resonance
更新于2025-09-09 09:28:46
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Robust Optimization of Nanoslit Array Sensor Based on Extraordinary Optical Transmission
摘要： A robust optimization approach for plasmonic periodic array sensor based on extraordinary optical transmission is proposed using Kriging surrogate models to reduce the effects of uncertainty in various manufacturing processes while maintaining sensor performance. For systematic design with reasonable computation cost, the author adopt the universal Kriging models whose regression function is a polynomial. The gradient index and the multiobjective genetic algorithm are chosen as a robustness measure and a global optimization tool, respectively. The figure of merit and the gradient index are set as two objective functions, and the design variables are the slit width and height, respectively. The optical properties of interest are investigated using the finite-element method. The numerical optimization results show the proposed scheme to be powerful and efficient in designing nanoslity array sensors based on extraordinary optical transmission with fabrication uncertainty.
关键词： gradient index,robust optimization,Plasmonics,surface plasmon polariton,multiobjective optimization,Kriging model
更新于2025-09-09 09:28:46
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Influence of the Substrate to the LSP Coupling Wavelength and Strength
摘要： Three kinds of typical structures, hemi-/spherical nanoparticles/nanoparticle dimers on the substrate and spherical nanoparticles/nanoparticle dimers half-buried into the substrate, are used for FDTD simulation to theoretically discuss the influence of the substrate to the localized surface plasmon (LSP) coupling when the metal nanoparticles/nanoparticle dimers are locating near a substrate. Simulated results show that the dependencies between the LSP coupling wavelength and the refractive index of the substrate for different structures are not the same, which can be attributed to the different polarization field distributions of LSPs. When light is incident from different directions, the LSP coupling strength are not the same as well and the ratios of the scattering peak intensities depend on the position of the metal nanoparticles or nanoparticle dimers. These phenomenon can be explained by the difference of the local driving electric field intensities which is modulated by the interface between the air and the substrate.
关键词： Resonance wavelength,Dielectric interface,Localized surface plasmon,Coupling strength
更新于2025-09-09 09:28:46
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Copolymer template etching for Au nanoparticles self-assembly
摘要： In this paper, we report a study on self-assembly of Au colloids assisted by polystyrene (PS)-polymethyl methacrylate (PMMA) block copolymer templates. Etching PMMA cylindrical domains of PS-PMMA thin films provides large-scale arrays of holes in which 12nm Au colloids may fall into. We demonstrate that the holes’ functionalisation with aminosilanes favours the deposition of the Au colloids into the holes. The extinction spectroscopy measurements demonstrate that the Au NPs which are self-assembled using this process do not present any aggregation. Such a process should pave the way for designing plasmonic devices like optical nanosensors.
关键词： optical nanosensor,localised surface plasmon resonance,copolymer template,metallic nanoparticles,self-assembly
更新于2025-09-09 09:28:46
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Measuring the plasma-wall charge by infrared spectroscopy
摘要： We show that the charge accumulated by a dielectric plasma-facing solid can be measured by infrared spectroscopy. The approach utilizes a stack of materials supporting a surface plasmon resonance in the infrared. For frequencies near the Berreman resonance of the layer facing the plasma the re?ectivity dip —measured from the back of the stack, not in contact with the plasma— depends strongly on the angle of incidence making it an ideal sensor for the changes of the layer’s dielectric function due to the polarizability of the trapped surplus charges. The charge-induced shifts of the dip, both as a function of the angle and the frequency of the incident infrared light, are large enough to be measurable by attenuated total re?ection setups.
关键词： Berreman resonance,surface plasmon resonance,plasma-wall charge,attenuated total re?ection,infrared spectroscopy
更新于2025-09-09 09:28:46
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Surface plasmon resonance, photoluminescence and surface enhanced Raman scattering behaviour of Ag/ZnO, ZnO/Ag and ZnO/Ag/ZnO thin films
摘要： The surface plasmon resonance (SPR) of Ag thin films in ZnO/Ag, Ag/ZnO bilayers and ZnO/Ag/ZnO multilayers produced by vacuum thermal evaporation has been studied. The role of thickness of the individual layers in the range of 5-50 nm was investigated. Detailed studies were carried out by fixing the thickness of the plasmon active layer and varying the dielectric layer thickness and vice versa. These studies reveal that the SPR of Ag is very sensitive to the geometry of the structures and as a consequence it has a strong effect on the photoluminescence (PL) as well as Surface enhanced Raman Scattering (SERS) behaviour. The PL peak of 5 nm thickness pure ZnO films which was centred at around 370 nm, was red shifted at higher thickness of 50 nm. Further, this peak was blue shifted to 324 nm when a 5 nm thickness Ag layer is introduced underneath the ZnO layer. The SERS behaviour of these structures was tested using R6G as the analyte. The enhancement factor for a 5 nm thickness pure Ag film was found to be 5x103. The highest enhancement factor for ZnO/Ag, Ag/ZnO and ZnO/Ag/ZnO trilayer films was found to be 7.4x106, 4.4x105 and 8.9x104, respectively.
关键词： surface plasmon resonance,surface enhanced Raman scattering,photoluminescence,Ag-ZnO multilayer films
更新于2025-09-09 09:28:46
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SURFACE-PLASMON-POLARITONS AT THE INTERFACE OF NANOSTRUCTURED METAMATERIALS
摘要： The rigorous modeling and analysis of surface waves at the boundary of two metamaterials are presented. The nature of the phenomenon of the surface-plasmon-polaritons and the in?uence of various parameters on it are investigated. We have analyzed the properties of structures incorporating nanostructured metamaterials. Surface-plasmon-polaritons at the interface of such metamaterials are studied. We demonstrate the ways to control the properties of the surface waves. Each metamaterial comprises alternating metal and dielectric layers. We analyze the dependence of the dispersion characteristics on the materials employed in metal-dielectric compound. The consistency of the dispersion diagrams and e?ective permittivity is studied. The Drude model is introduced in the metal dispersion in order to take into account the e?ects of the structure on dielectric properties.
关键词： nanostructured,surface-plasmon-polaritons,Drude model,metamaterials,dispersion characteristics
更新于2025-09-09 09:28:46
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EFFICIENT ANALYSIS OF ELECTROMAGNETIC FIELDS FOR DESIGNING NANOSCALE ANTENNAS BY USING A BOUNDARY INTEGRAL EQUATION METHOD WITH FAST INVERSE LAPLACE TRANSFORM
摘要： In this paper, we investigate electromagnetic problems for nanoscale antennas by using a boundary integral equation method with fast inverse Laplace transform. The antennas are designed for realizing ultra-fast and high-density magnetic recording. Characteristics of nanoscale antennas are discussed in terms of eigenmodes and time domain responses of electric ?elds. Our computational method is highly e?cient and the computational cost can be reduced by selecting coarse time-step size and performing parallel computation.
关键词： fast inverse Laplace transform,plasmon resonances,nanoscale antennas,electromagnetic fields,boundary integral equation method
更新于2025-09-09 09:28:46