Index ellipsoid: wave equation and dispersion relation

This lecture covers the derivation of the wave equation in a dielectric medium, considering isotropic and linear properties. It also explores the dispersion relation and the concept of the index ellipsoid, showing how the refractive index depends on the frequency. The continuity equation for energy conservation in the presence of a charge is discussed, along with the power received by the charge. The lecture delves into the complex index of refraction, the damped harmonic oscillator model, and the quantum formalism for computing susceptibility. It concludes with the symmetry of the dielectric tensor and the optical properties of anisotropic materials.