Fluctuations and light scattering in liquid crystals

The review is devoted to theoretical and experimental problems in the study of liquid crystals by light scattering methods. Nematic, cholesteric, and smectic liquid crystals in the isotropic and ordered phases are considered. The possible types of fluctuations are discussed for each phase. In the isotropic phase, special attention is devoted to pretransition phenomena. The influence on light scattering by unusual properties of liquid crystals such as the marked anisotropy, gyrotropy, and the presence of a regular periodic structure is examined in detail. The characteristic features of Green's function of Maxwell's equations for such media are discussed. The influence of the finite size and of the surface effects in the liquid crystal on the fluctuations and light scattering is considered. The problem of taking into account multiple scattering is discussed. The theoretical results are illustrated by the available experimental data.