Surface plasmon polariton excitations

Fig. 16.2 Localized surface plasmon polariton excited at the metallic tip apex...

SCATTERED LIGHT AND EMISSION FROM Ag THIN FILM AND MEROCYANINE LANGMUIR-BLODGETT FILM ON Ag THIN FILM DUE TO SURFACE PLASMON POLARITON EXCITATION... 

Enhancement of Photocurrents in Merocyanine LB Film Cell Utilizing Surface Plasmon Polariton Excitations... 

Blodgett Film on Ag Thin Film due to Surface Plasmon Polariton Excitation... 

Fig. 6.19 Surface plasmon polariton excitation energy for poiycrystaiiine Ag and Au eieotrodes in 0.5 M NaCi04 as a function of the eiectrode po-tentiai. The potentiais of zero charge are marked by arrows. Reprinted from (KStz et ai. 1977), Copyright 1977, with permission from Eisevier.

Kolb, D. (1982). The study of solid-liquid interfaces by surface plasmon polariton excitation. In Agranovich, V. and Mills, D., editors. Surface PoUritons, pages 299 - 329. North-HoUand Publishing Company. 

Figure 3. Optical excitation of surface plasmon-polaritons (surface plasmon) by the attenuated...

Hayazawa, N., Ishitobi, H., Taguchi, A., Ikeda, K., Tarun, A., and Kawata, S. 2007a. Focused excitation of surface plasmon polaritons for efhcient held enhancement based on gapmode in tip-enhanced spectroscopy. Jpn. J. Appl. Phys. 46 7995-99. 

At the surface of metals, the surface plasmon-polaritons, also called "surface plasmons," are not the same as the "bulk" plasmons these surface plasmons are affected (i.e., shifted slightly in energy) by monolayer adsorbates thus Surface Plasmon Resonance (SPR) spectroscopy yields information about the nature of the binding of the adsorbates onto a metal surface. The surface plasmons are excited by a p-polarized electromagnetic wave (polarized in the plane of the film) that crosses a glass medium (1), such as a prism, and is partially reflected by a metallic film (2) and back into the glass medium the dispersion relation is... 

Surface plasmons, or surface plasmon polaritons, are surface electromagnetic waves that propagate inside a metal along a metal/dielectric (or metal/ vacuum) interface their excitation by light is surface plasmon resonance (SPR) for planar surfaces or localized surface plasmon resonance (LSPR) for nanometer-sized metal particles. 

Januts NA, Baghdasaryan KS, Nerkarayan KV et al (2005) Excitation and superfocusing of surface plasmon polaritons on silver coated optical fiber tip. Opt Commun 259 118-124... 

No doubt, the present author has his own private consensus which, in spite of his efforts, may inject itself into the review. In order to offset such an undesirable bias, as much as possible, and perhaps putting the cart before the horse, the author will state here his own conclusions and beliefs I am convinced that electric field amplification and enhanced emission near SERS-active surfaces due to resonating metal excitations (surface-plasmon polaritons, plasmonlike modes, shape resonances, or electron-hole pairs) is an active mechanism in most of the systems studied. However, in most systems, this contribution, though an important one, is minor compared to the total enhancement possible in SERS. The major mechanism, in my opinion, must be a resonance mechanism, in the sense of a resonance Raman process, i.e., a mechanism by which a part of the system (molecule, molecule-metal atoms, metal surface) becomes a strong scatterer by virtue of its large resonance polarizability and not as a result of strong fields exerted by the other parts of the system . 

The enhancement of the electromagnetic fields at the surface of an internally reflecting crystal arise via the excitation of surface plasmon polaritons (SPP) [30] by the incident IR light. These SPPs are collective electronic excitations at metal surfaces and, theoretically, provide a sensitive probe of the optical properties of the interfacial region via resonance with the in-... 

Collective optical excitations, like surface plasmon-polaritons in partially-ordered metal nanoparticle arrays, tend to be spatially localized. The localization facilitates a giant increase of linear and nonlinear optical responses such as Raman scattering, enhancement of spontaneous emission rate, nonlinear absorption and refraction. In this paper the spectral manifestation of light localization into metal-dielectric nanocomposites i s s tudied i n t he visible. T he e ffect o f t he 1 ateral e lectrodynamic coupling on transmission/reflection optical spectra is investigated for planar silver nanoparticle arrays (random close-packed and polycrystalline quasiregular structures). Combined action of electron and photon confinements is demonstrated experimentally and considered theoretically for ID-photonic crystals consisted of a metal nanoparticle stratified array. 

As noted above, previous reports of the SEIRA effect had attributed the enhancement to a similar mechanism similar to the one leading to the SERS effect, namely the excitation of surface plasmon polaritons. " Because the effect was observed with Ni, Pt and Pd as well as Ag, Nakao and Yamada recognized that the effect that they observed was caused by some mechanism other than the effect of excitation of surface plasmon polar-itons. Nakao and Yamada postulated that the effect of multiple reflection in the metal film, of the decrease in penetration depth of the IRE caused by the metal layer and/or the effect of local (chemical) interaction at the metal-sample interface might contribute to the enhancement. However, as will be discussed later in this chapter, none of these putative causes fully explains the enhancement. 

The application of the ATR method in Raman spectroscopy provides a unique way to study essentially mirrorlike polished metals, in particular single crystalline surfaces. The ATR method is used to excite surface plasmon polaritons (SPPs) effectively at the smooth metal surface, to improve the sensitivity in Raman spectroscopy by electromagnetic field enhancement [19]. The enhancement of the ATR configuration, as shown in Figs. 8(d and e), with respect to the normal external reflection geometry spans one to three orders, depending on the electrodes and their crystallographic orientations. 

The electromagnetic enhancement mechanism features the major contribution to the overall enhancement of SERS. It is based on the generation of an electromagnetic field at the surface of nanostructured metal surfaces due to the interaction of an incident electromagnetic field and the excitation of localized surface plasmon polaritons. To explain this phenomenon in more detail, a simple model can be used. A simple metal nanosphere with a size smaller than the wavelength of the incident light is considered for this purpose. This metal nanosphere is surrounded by a medium or vacuum with a dielectric constant Eq, and all appearing processes are assumed to be quasi-static. The dielectric constant inside the metal nanosphere is independent of the size of the sphere and is described as follows ... 

Figure 1.16 Imaginary part of the complex polarizability a o)) for an Na cluster with N = 198 in units of Effective single-pair excitations, as well as the surface plasmon and the volume plasmon, are clearly resolved. For comparison the result of the local Drude theory is also given. In this case there is only one mode of excitation, the classical surface-plasmon polariton or Mie-resonance at coply/3. Because the frequency is scaled with this frequency the Drude curve peaks trivially at 1. For more explanation see text. Reproduced with permission from Reference [5]. Copyright 1985 by the American Physical Society...

Figure 1(a) shows the Kretschmann configuration [9] for the excitation of plasmon surface polaritons (surface plasmons for short) [10] in the attenuated total reflection (ATR) mode. When a p-polarized laser beam is irradiated at the (internal) incident angle 9t from the prism of a refractive index np above 6c, a strong nonradiative electromagnetic wave, i.e. a surface plasmon is excited at the resonant angle which propagates at the metal /electrolyte interface. 

In the attenuated total reflection (ATR) method, surface plasmon polaritons (SPPs) are resonantly excited on surface of metal thin films by the incident light, and remarkably strong absorption of the incident light occurs due to the resonantly excited SPPs[5,6]. Therefore, photoelectric effects in the cells are expected to be improved by utilizing the ATR method exciting the SPPs[7,8]. 

Depending on the substrate excitations which are coupled with light into the SP mode, one distinguishes surface plasmon polaritons, surface phonon polaritons, surface exciton polaritons, etc. In this section we shall consider surface plasmon polaritons in some detail. This type of electromagnetic wave was first discussed by Sommerfeld in connection with the propagation of radiowaves along the Earth s surface (Sommerfeld 1909). 

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