Light electromagnetic field theory

Surface plasmons (SPs) are collective electronic excitations near the surfaces of metallic structures. They can usually be described well with classical electromagnetic theory and correspond to electromagnetic fields that are localized and relatively intense near the metallic surfaces [1, 2]. These properties make them potentially useful for a variety of applications in optoelectronics, chemical and biological sensing, and other areas. Metallic nanostructures such as metal nanoparticles and nanostructured thin metal films, particularly those composed of noble metals such as silver or gold, are of special interest because often their SPs can be excited with visible-UV light and are relatively robust. 

A great deal of research by many investigators led to the formulation of a theory of electromagnetic field (EM) enhancement, which occurs when small metal particles are illuminated by light of suitable wavelength. The following characteristics are a distillation of approximately 15 years of research into the origin of enhanced Raman results of EM field enhancement that are relevant to analytical applications. 

Baev et al. review a theoretical framework which can be useful for simulations, design and characterization of multi-photon absorption-based materials which are useful for optical applications. This methodology involves quantum chemistry techniques, for the computation of electronic properties and cross-sections, as well as classical Maxwell s theory in order to study the interaction of electromagnetic fields with matter and the related properties. The authors note that their dynamical method, which is based on the density matrix formalism, can be useful for both fundamental and applied problems of non-linear optics (e.g. self-focusing, white light generation etc). 

If the condition in Equation 5.406 is violated, the RDG theory is not valid. A solution of the scattering problem for particles arbitrary in size has been found only for several particular shapes. Mie " succeeded in finding a complete general solution of the Maxwell equations for a sphere in a periodic electromagnetic field. The refractive indices of the sphere, n, and of the medium, n , are considered to be complex numbers (i.e., the theory is applicable to light-absorbing substances, including metals) ... 

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