TABLE OF CONTENTS The experimental methods presented in this monograph concern the interaction of light with complex materials for the purpose of elucidating aspects of structure and dynamics. The interactions range from simple transmission and reflection, to scattering and nonlinear responses. Measurement of changes in the properties of the light (polarization, intensity, or frequency) is used to infer the microstructural characteristics of the sample and for this reason, the basic nature of light propagation in macroscopic media must be understood. This chapter presents the basic field equations governing the propagation of electromagnetic waves and the boundary conditions by which they are constrained.
Electromagnetic waves combine the propagation of two vector fields, E and B. These are the electric and magnetic induction fields, respectively, and in a vacuum are governed by the Maxwell equations 1, 2, 3]:
where ? 0 and ? 0 are the permittivity and permeability of free space. The density of charges in the system, ?(x), and the current density, J (x), obey the following equation of continuity:
Equation (1.2) is not independent and is obtained by combining the first two equations in (1.1).
Light propagating within a medium will interact with the constituent molecules or particles and the induction fields E and B will be altered. In principle, the equations in (1.1) can be applied to any situation as long as the charge and current densities are specified. In a condensed media, however, this approach is not practical...
