Optical properties local field

From comparison of the optical properties of particles deposited on the same substrate and differing by their organization (Figs. 7 and 8) it can be concluded that the appearance of the resonance peak at 3.8 eV is due to the self-organization of the particles in a hexagonal network. This can be interpreted in terms of mutual dipolar interactions between particles. The local electric field results from dipolar interactions induced by particles at a given distance from each other. Near the nanocrystals, the field consists of the ap-... 

While the linear absorption and nonlinear optical properties of certain dendrimer nanocomposites have evolved substantially and show strong potential for future applications, the physical processes governing the emission properties in these systems is a subject of recent high interest. It is still not completely understood how emission in metal nanocomposites originates and how this relates to their (CW) optical spectra. As stated above, the emission properties in bulk metals are very weak. However, there are some processes associated with a small particle size (such as local field enhancement [108], surface effects [29], quantum confinement [109]) which could lead in general to the enhancement of the fluorescence efficiency as compared to bulk metal and make the fluorescence signal well detectable [110, 111]. 

P. Ye and Y. R. Shen, Local field effect on linear and nonlinear optical properties of... 

In general, (Eioc) 5 E, since the local electric field is averaged over the atomic sites and not over the spaces between these sites. In metals, where valence electrons are free (nonlocalized electrons), the assumption (Eioc) = E is reasonable, but for bound valence electrons (dielectrics and semiconductors) this relation needs to be known. However, for our purpose of a qualitative description of optical properties, we will still retain this assumption. 

The supporting medium (aqueous or organic solvents membrane-mimetic compartments) also has a profound influence on the optical and electro-optical properties of nanosized semiconductor particles. This dielectric confinement (or local field effect) originates, primarily, in the difference between the refractive indices of semiconductor particles and the surrounding medium [573, 604], In general, the refractive index of the medium is lower than that of the semiconductor particle, which enhances the local electric field adjacent to the semiconductor particle surface as compared with the incident field intensity. Dielectric confinement of semiconductor particles also manifests in altered optical and electro-optical behavior. 

NSOM methods can provide extremely valuable information about the functional properties of optical and optoelectronic materials.243 In many such applications, electrical potentials and/or electric fields are applied to samples as a means to induce changes in the local optical properties of the sample. Frequently, an electrified NSOM probe is employed in these studies.244 The resulting changes in... 

Still within a continuum solvation approach [22,41], a unified treatment of the local field problem has recently been formulated within PCM for (hyper)polarizabilities [47] and extended to several optical and spectroscopic properties, including IR, Raman, VCD and VROA spectra [8,9,11,12],... 

The interactions between the molecule and the environment can lead to distortions in the electrical properties due to the susceptibility of the molecules and the properties of the host matrix. The refractive index of the matrix acts as a screening factor, modifying the optical spectra and interaction between charges or dipoles embedded within it. Local field effects change the interaction with an electromagnetic field and should be considered along with orientation factors in the dipolar interaction. 

Reflection at a surface of a beam of linearly polarized photons alters the direction and amplitude of the electric and magnetic vectors. It is these differences between incident and reflected beams that give information concerning surface structure, as they depend on the interaction of the beam with the electronic distribution and with the associated local electric and magnetic fields on the surface. The phase and amplitude change for the vectors is different for the component parallel to the plane of incidence than for the component perpendicular to it. The result is a vector that follows a spiral during its propagation, and is referred to as elliptically polarized, Fig. 12.2. A deeper treatment of these optical properties can be found in Ref. 9. Such measurements are referred to as specular reflectance. 

Metal nanostructures (such as particles and apertures) can permit local resonances in the optical properties. These local resonances are referred to as localized surface plasmons (LSPs). The simplest version of the LSP resonance comes for a spherical nanoparticle, where the electromagnetic phase-retardation can be neglected in the quasi-static approximation, so that the electric field inside the particle is uniform and given by the usual electrostatic solution [3] ... 

Sipe JE, Boyd RW (2002) Nanocomposite materials for nonlinear optics based on local field effects, in optical properties of nanostructured random media, 82nd edn. Springer, Berlin, pp 1-19... 

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