The study of the propagation of light through matter, particularly solid matter, comprises one of the important and interesting branches of optics. The many and varied optical phenomena exhibited by solids include such things as selective absorption, dispersion, double refraction, polarization effects, and electro-optical and magneto-optical effects. Many of the optical properties of solids can be understood on the basis of classical electromagnetic theory. The present chapter applies the macroscopic Maxwell theory to the propagation of light through solids. The microscopic origin of the optical properties of solids will be treated classically, since the quantum-theoretical treatment is beyond the scope of this book. But the way in which the phenomena are described by the classical theory gives considerable physical insight and helps to provide a fundamental background for later study.RetryReason
6.2 Macroscopic Fields and Maxwell's EquationsRetryReason
The electromagnetic state of matter at a given point is described by four quantities:RetryReason
The volume density of electric charge rho\rhoRetryReason
The volume density of electric dipoles, called the polarization P\mathbf{P}RetryReason
The volume density of magnetic dipoles, called the magnetization M\mathbf{M}RetryReason
The electric current per unit area, called the current density J\mathbf{J}RetryReason
All of these quantities are considered to be macroscopically averaged in order to smooth out the microscopic variations due to the atomic makeup of all matter. They are related to the macroscopically averaged fields E\mathbf{E} and H\mathbf{H} by the following Maxwell equations:RetryReason
If one introduces the abbreviation D\mathbf{D} for the quantity epsilon_(0)E+P\epsilon_{0} \mathbf{E}+\mathbf{P}, known as the electric displacement, and the abbreviation B\mathbf{B} for mu_(0)(H+M)\mu_{0}(\mathbf{H}+\mathbf{M}), called the magnetic induction, then Maxwell’s equations assume the more compact forms:RetryReason
grad xxE=-(delB)/(del t)\boldsymbol{\nabla} \times \mathbf{E}=-\frac{\partial \mathbf{B}}{\partial t}
grad xxH=(delD)/(del t)+J\nabla \times \mathbf{H}=\frac{\partial \mathbf{D}}{\partial t}+\mathbf{J}