Optical Processes In Solids

A unifying element that links the apparently diverse phenomena observed in optical processes is the dielectric dispersion of matter. It describes the response of matter to incoming electromagnetic waves and charged particles, and thus predicts their behavior in the self-induced field of matter, known as polariton and polaron effects. The energies of phonon, exciton and plasmon, quanta of collective motions of charged particles constituting the matter, are also governed by dielectric dispersion. Since the latter is a functional of the former, one can derive useful relations for their self-consistency. Nonlinear response to laser light inclusive of multiphoton processes, and excitation of atomic inner shells by synchrotron radiation, are also described. Within the configuration coordinate model, photo-induced lattice relaxation and chemical reaction are described equally to both ground and relaxed excited states, to provide a novel and global perspective on structural phase transitions and the nature of interatomic bonds. This book was first published in 2003.

Optical Properties of Solids covers the important concepts of intrinsic optical properties and photoelectric emission. The book starts by providing an introduction to the fundamental optical spectra of solids. The text then discusses Maxwell's equations and the dielectric function; absorption and dispersion; and the theory of free-electron metals. The quantum mechanical theory of direct and indirect transitions between bands; the applications of dispersion relations; and the derivation of an expression for the dielectric function in the self-consistent field approximation are also encompassed. The book further tackles current-current correlations; the fluctuation-dissipation theorem; and the effect of surface plasmons on optical properties and photoemission. People involved in the study of the optical properties of solids will find the book invaluable.

This book presents an account of the course "Optical Properties of Excited States in Solids" held in Erice, Italy, from June 16 to 3D, 1991. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the "Ettore Majorana" Centre for Scientific Culture. The purpose of this course was to present physical models, mathematical formalisms and experimental techniques relevant to the optical properties of excited states in solids. Some active physical species, such as ions or radicals, could survive indefinitely if they were completely 'isolated in space. Other active species, such as excited molecular and solid-state systems, are inherently unstable, even in isolation, due to the spontaneous mechanisms that may convert their excitation energies into radiation or heat. Physical parameters that may be used to characterize these excited systems are the localization or delocalization, and the coherence or incoherence, of their state excitations. In solids the excited states, whether they are localized (as for impurities in insulators) or delocalized (as they may occur in semiconductors), are relevant in several regards. Their de-excitation is extremely sensitive to the nature of the excitations of the systems, and a study of the de-excitation processes can yield a variety of information. For example, the excited states may represent the initial condition of the onset of such processes as Stokes-shifted emission, hot luminescence, symmetry-dependent Jahn-Teller and scattering processes, tunneling processes, energy transfer to like and unlike centers, superradiance, coherent radiation, and excited state absorption.

An exciton is an electronic excitation wave consisting of an electron-hole pair which propagates in a nonmetallic solid. Since the pioneering research of Fren kel, Wannier and the Pohl group in the 1930s, a large number of experimental and theoretical studies have been made. Due to these investigations the exciton is now a well-established concept and the electronic structure has been clarified in great detail. The next subjects for investigation are, naturally, dynamical processes of excitons such as excitation, relaxation, annihilation and molecule formation and, in fact, many interesting phenomena have been disclosed by recent works. These excitonic processes have been recognized to be quite important in solid-state physics because they involve a number of basic interactions between excitons and other elementary excitations. It is the aim of this quasi monograph to describe these excitonic processes from both theoretical and experimental points of view. we take a few To discuss and illustrate the excitonic processes in solids, important and well-investigated insulating crystals as playgrounds for excitons on which they play in a manner characteristic of each material. The selection of the materials is made in such a way that they possess some unique properties of excitonic processes and are adequate to cover important interactions in which excitons are involved. In each material, excitonic processes are described in detail from the experimental side in order to show the whole story of excitons in a particular material.

An overview of the optical effects in solids, this book addresses the physics of materials and their response to electromagnatic radiation--back cover.

Although much work has been performed on measure ments and interpretation of light absorption by opaque or nearly opaque solids, it is surprising to note that until recently relatively little reliable experimental data, and much less theoretical work was available on the nature of transparent solids. This, in spite of the fact that a vast majority of engineering and device ap plications of a solid depend on its optical transparency. Needless to say, all solids are both transparent and opa que depending on the spectral region of consideration. The absorption processes that limit the transparency of a solid are either due to lattice vibrations, as in ionic or partially ionic solids, or due to electronic transi tions, both intrinsic and impurity-induced. For most materials, a sufficiently wide spectral window exists be tween these two limits, where the material is transpar ent. In general, the absorption coefficient, in the long wavelength side of, but sufficiently away from, the fun damental absorption edge, is relatively structureless and has an exponential dependence on frequency. Recent evi dence suggests that in the short wavelength side of the one-phonon region, but beyond two- or three-phonon sin gularities, the absorption coefficient of both polar and nonpolar solids is also relatively structureless and de pends exponentially on frequency.