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1.
Existing theories concerning the life-time of surface plasmons in small metal particles fail to explain recent experimental data for silver. Therefore, two of these theories were critically re-examined, and some numerical errors were found. The semi-classical approach by Lozovik et al. yields, after correction, physically reasonable results, which are nearly identical with theoretical results by Kreibig. The corrected RPA-result by Lushnikov et al. is in quantitative agreement with recent experimental data for silver. 相似文献
2.
It is shown that the experimentally found red shift of the surface plasmon resonance in a small metal particle is a direct measure of the first moment of the induced surface charge. 相似文献
3.
The dielectric response of a small metal particle to a perturbing potentialv L =r L Y LM e iωt is considered within the random phase approximation (RPA). The static dielectric polarizability is found and the size dependence of the surface plasmon frequencies are then determined from sum rule calculations. When the particle radiusa is large compared to the Thomas-Fermi screening lengthr 0 the RPA equation is transformed into a form appropriate for an analytical solution. The dynamic electric polarizability, the position and the width of the surface plasma resonance are found in the limita/r 0?1. 相似文献
4.
The cross sections for excitation of surface plasmons by fast electrons and x rays are calculated within the random phase approximation for a spherical metal particle. The results are compared with those obtained within the hydrodynamic model of a free electron gas. 相似文献
5.
Positions of two surface plasma resonances in a layer metal particle containing a dielectric foreign nucleus are calculated within the random phase approximation. The results obtained give a possible explanation of a recent experimental observation by Genzel et al.1 of two peak structure in the photoabsorption cross-section of small silver particles. 相似文献
6.
On the assumption that the resonant surface plasmons on a spherical nanoparticle are formed by standing waves of two counter-propagating surface plasmon waves along the surface, by using Mie theory simulation, we find that the dispersions of surface plasmon resonant modes supported by silver nanospheres match with those of the surface plasmons on a semiinfinite medium-silver interface very well. This suggests that the resonant surface plasmons of a metal nanosphere can be treated as a propagating surface plasmon wave. 相似文献
7.
《中国物理 B》2015,(5)
We present a modified method to solve the surface plasmons(SPs) of semi-infinite metal/dielectric superlattices and predicted new SP modes in physics. We find that four dispersion-equation sets and all possible SP modes are determined by them. Our analysis and numerical calculations indicate that besides the SP mode obtained in the original theory, the other two SP modes are predicted, which have either a positive group velocity or a negative group velocity. We also point out the possible defect in the previous theoretical method in accordance to the linear algebra principle. 相似文献
8.
Surface enhanced Raman scattering of pyridine adsorbed to weakly roughened silver films is studied using a well-characterized extended surface plasmon excitation. We show that the additional increase in the Raman signal associated with the extended surface plasmon is fully accounted for by the enhancement in the average macroscopic field. 相似文献
9.
Under the quasistatic approximation, the characteristics of a local plasmon resonance of a metal nanostructure exhibit several general properties. The resonance frequency depends on the fraction of plasmon energy residing in the metal through the real dielectric function of the metal. For a given resonant frequency, the Q factor of the resonance is determined only by the complex dielectric function of the metal material, independent of the nanostructure form or the dielectric environment. A simple result describing the effect of optical gain on the Q factor is also obtained. 相似文献
10.
等离子体激元(surface plasmon polaritons, SPP)因其独特的光学和物理特性, 使其具有诸如透射增强和局域共振等一系列新颖现象, 已成为当前国内外学者研究的热点. 本文对基于类表面等离子体激元(Spoof Surface Plasmons, SSP)的矩形金属光栅色散特性和模式分布进行了研究. 利用本征函数法并结合场匹配条件, 获得了矩形栅表面SSP的场表达式、色散关系和模式分布, 并通过电磁仿真进行了验证. 在此基础上分析了矩形栅各参数对SSP色散及模式分布的影响, 研究结果表明: 由本征函数法获得的SSP色散特性与仿真结果基本符合; 增大金属栅高度或减小排列周期能减小SSP的相速度; 而增大金属栅周期占空比能在一定程度上拓展SSP与电子束互作用的带宽; 改变金属盖板高度对慢波SSP色散模式基本没有影响; 减小金属栅侧面宽度能增大模式之间的间隔, 从而能有效避免模式竞争的发生. 本文对基于SSP的矩形金属光栅色散特性的研究将为进一步研究SSP与电子束的相互作用, 形成高效、宽带的新型太赫兹源奠定良好的理论基础. 相似文献
11.
Z. Liu D. Xi D. Pile Q. Luo N. Fang X. Zhang 《Applied Physics A: Materials Science & Processing》2007,87(2):157-160
Surface plasmon and its potential application in nanotechnology have attracted a remarkable amount of attention recently due
to their novel properties. In this work we present an angularly resolved surface plasmon scattering study on a primitive metal
surface. Using a reversed attenuated total reflection (RATR) setup in the experiment, we obtained a double-crescent shaped
and enhanced scattering pattern at far field. The scattering pattern as a function on the variation of angle and polarization
of incident beam are studied. Both theoretical and experimental results reveal an enhanced backward scattering by surface
plasmon excitation. Consequently, it is shown that this angularly resolved surface plasmon scattering measurement can be employed
for resolving a richness of nanoscale surface textures.
PACS 42.79.-e; 42.30.Wb; 78.20.Ci 相似文献
12.
13.
M.A. Noginov G. Zhu M. Bahoura J. Adegoke C. Small B.A. Ritzo V.P. Drachev V.M. Shalaev 《Applied physics. B, Lasers and optics》2007,86(3):455-460
The compensation of loss in metal by gain in interfacing dielectric has been demonstrated in a mixture of aggregated silver
nanoparticles and rhodamine 6G dye. An increase of the quality factor of surface plasmon (SP) resonance was evidenced by the
sixfold enhancement of Rayleigh scattering. The compensation of plasmonic losses with gain enables a host of new applications
for metallic nanostructures, including low- or no-loss negative-index metamaterials.
We have also predicted and experimentally observed a suppression of SP resonance in metallic nanoparticles embedded in dielectric
host with absorption.
PACS 61.46.Df; 73.20.Mf; 78.67.Bf 相似文献
14.
15.
The possibilities of a recently proposed (Opt. Express 17, 9323 (2009)) method for generating terahertz surface plasmons on
a microstructured (comb-shaped) metal surface using a nonlinear polarization pulse that moves with a superluminal velocity
and is induced by an ultrashort laser pulse in a strip of electrooptic material deposited on the surface are theoretically
studied. For an arbitrary direction of motion of the nonlinear source along the comb-shaped surface, fields of excited terahertz
plasmons and the angular spectral distribution of the radiated energy are calculated. It is shown that the spectral and energy
characteristics of plasmons can be efficiently controlled by varying the direction of motion of the source. Conditions (parameters
of the comb-shaped structure, direction and velocity of motion of the source) that ensure the maximal efficiency of the optical-to-terahertz
conversion are found. The developed method of terahertz generation is promising for surface terahertz spectroscopy. 相似文献
16.
《Superlattices and Microstructures》1994,15(4):459-462
Samples consisting of Ag fine particles 4nm in size placed near to an Al surface were prepared by depositing Ag-SiO2 composite films by a rf cosputtering method onto vacuum-evaporated Al films. Angle-scan attenuated total reflection (ATR) measurements were performed over a wide wavelength range (λ=350-630nm) covering the resonance region (λ-410nm) of localized surface plasmon (LSP) in the Ag particles. It was found that the existence of Ag fine particles near to the Al surface led to a deformation of the dispersion curve of the surface plasmon polariton (SPP) propagating on the Al surface, in particular, in the LSP resonance region. The interaction between LSP and SPP was found to become much stronger as the distance between the particles and the surface decreases. The theoretical calculations based on the effective medium theory, which gave an effective dielectric function of the Ag-SiO2 composite film, reproduced the deformation of the dispersion curve of the SPP. The deformation of the dispersion observed experimentally was qualitatively explained by the behavior of the effective dielectric function of the Ag-SiO2 composite film. 相似文献
17.
This paper is an extension of the authors' earlier work to include a treatment of onephonon inelastic scattering of particles which do not penetrate appreciably into the crystal. A full quantum-mechanical treatment of the lattice vibrations is used throughout, and the results are not restricted to small scattered intensities. Calculations are presented for the scattering of helium atoms by a simplified model of the crystal surface. 相似文献
18.
The second-order processes of optical-rectification and photoconduction are well known and widely used to produce ultrafast electromagnetic pulses in the terahertz frequency domain. We present a new form of rectification that relies on the excitation of surface plasmons in metal films deposited on a shallow grating. Multiphoton ionization and ponderomotive acceleration of electrons in the enhanced evanescent field of the surface plasmons results in a femtosecond current surge and emission of terahertz electromagnetic radiation. Using gold, this rectification process is third or higher-order in the incident field. 相似文献
19.
V. I. Psarev 《Russian Physics Journal》1968,11(7):33-35
A consideration of the change in thickness of the diffusion zone and of the rate of attachment of material to the faces of particles during diffusion coagulation leads to a general expression for the size distribution function of the dispersed particles. The form of the distribution function and its variation with time illustrate the diversity of the experimentally observed unimodal distributions of the particles of the dispersed phases in metal alloys. 相似文献
20.
The statistical model of electrons in a small metallic particle is applied to calculate three expressions for the size dependent ac conductivity. The first expression is very simple. It is obtained with a sum-rule conserving ansatz for the electric dipole matrix element. The two other forms follow from generalizations of a quasiclassical approximation for the matrix element due to Gor'kov and Eliashberg. The results are discussed and related to other work.Dedicated to Professor W. Brenig on the occasion of his 60th birthday 相似文献