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We briefly review the contents of this as well as previous volumes of the series Light Scattering in Solids, and present a chronological account of the International Conference on Raman spectroscopy (ICORS).

A bibliometric study of early publications on the Raman effect is also presented together with a succint historical outline of the discovery of the effect and information recently made available about the Nobel Prize awarded to Sir Chandrasekhar Venkata Raman in 1930.

The modification of the optical properties of matter due to photon confinement in optical microcavities has been an active field of research in the last ten years. This review addresses the problem of Raman scattering in these optically confining structures. Two completely different regimes exist and will be discussed here. Firstly, a situation in which the action of the microcavity is basically to enhance, and to spatially and spectrally confine, the photon field, but otherwise the light-matter interaction process remains unaltered. This is the case when the laser and scattered photon energies are well below those of the excitonic transitions in the structure, or when the coupling between the latter and the cavity mode can be treated in a “weak coupling” approximation. This regime will be labeled here as “optical resonant Raman scattering”. And secondly, a “strong-coupling” regime in which exciton and cavity-photon modes cannot be treated separately, leading to coupled excitations, so-called cavity polaritons. In this second case, when the laser or scattered photons are tuned to the excitonic energies, and thus an electronic resonant Raman-scattering process is achieved, the Raman-scattering process has to be described in a fundamentally different way. This regime will be labeled as “cavity-polariton-mediated Raman scattering”.

The Chapter will begin, after a brief historical introduction, with a review of the fundamental properties of optical microcavities, and of the different strategies implemented to achieve double optical resonant Raman scattering in planar microcavities. A section will be then devoted to experimental results that highlight the different characteristics and potentialities of Raman scattering under optical confinement, including, in some detail, an analysis of the performance of these structures for Raman amplification. A subsequent section will present a series of research efforts devoted to the study of nanostructure phonon physics that rely on microcavities for Raman enhancement. In particular, emphasis will be given to recent investigations on acoustic cavities that parallel their optical counterparts but that, instead, confine hypersound in the GHz–THz range. The Chapter will then turn to a quite different topic, that of cavity-polariton-mediated scattering. The theory developed in the 1970s for bulk materials will be briefly introduced, and its modifications to account for photon confinement in planar structures will be addressed. Finally, a series of experiments that demonstrate the involvement of polaritons in the inelastic scattering of light in strongly coupled cavities will be reviewed. The Chapter will end with some conclusions and prospects for future developments on this subject.

The vibrational properties of single-walled carbon nanotubes reflect the electron and phonon confinement as well as the cylindrical geometry of the tubes. Raman scattering is one of the prime techniques for studying the fundamental properties of carbon tubes and nanotube characterization. The most important phonon for sample characterization is the radial-breathing mode, an in-phase radial movement of all carbon atoms. In combination with resonant excitation it can be used to determine the nanotube microscopic structure.

Metallic and semiconducting tubes can be distinguished from the high-energy Raman spectra. The high-energy phonons are remarkable because of their strong electron–phonon coupling, which leads to phonon anomalies in metallic tubes. A common characteristic of the Raman spectra in nanotubes and graphite is the appearance of Raman peaks that correspond to phonons from inside the Brillouin zone, the defect-induced modes. In this Chapter we first introduce the vibrational, electronic, and optical properties of carbon tubes and explain important concepts such as the nanotubes’ family behavior. We then discuss the Raman-active phonons of carbon tubes. Besides the vibrational frequencies and symmetries Raman spectroscopy also allows optical (excitonic) transitions, electron–phonon coupling and phase transitions in single-walled carbon nanotubes to be studied.

In this Chapter we discuss the use of resonant Raman scattering by acoustic phonons and its applications to the study of the spatial localization and spatial correlation of electronic wavefunctions in low-dimensional semiconductor and metallic systems. Special attention is paid to the simulation of the Raman spectra and their direct comparison with experimental data. We review the basic concepts of this field and results reported in the literature.

This Chapter presents the current status of phonon-dispersion studies using very high energy resolution inelastic X-ray scattering. The theoretical background and the instrumental principles are briefly summarized. This is followed by a representative selection of studies on single crystals and polycrystalline materials, including high-pressure work. The Chapter concludes with novel applications of the technique.

X-rays are a valuable probe for studying structural dynamics in solids because of their short wavelength, long penetration depth and relatively strong interaction with core electrons. Recent advances in accelerator- and laser-based pulsed X-ray sources have opened up the possibility of probing nonequilibrium dynamics in real time with atomic-scale spatial resolution. The timescale of interest is a single vibrational period, which can be as fast as a few femtoseconds. To date, almost all such experiments on this timescale have been carried out optically, which only indirectly measure atomic motion through changes in the dielectric function. X-rays have the advantage that they are a direct probe of the atomic positions.