Light Propagation in Matter:. from Polaritons to Photonic Crystals

In a first part of this contribution we calculate the optical properties of matter using the classical approach of the model Lorentz-oscillators, derive then the dispersion relation of light in matter and introduce the concept of polaritons when going to the quantum mechanical description.

In the second chapter the polariton concept is applied to three-dimensional ordered and amorphous matter like crystals, gases or alloys. The resonances by which we replace the model Lorentz oscillator are exctions, optical phonons, plasmons as well as transitions in the atomic electron system of Na vapour or in ⁵⁷Fe nuclei.

The third chapter is devoted to systems of reduced dimensionality like exciton polaritons in semiconductor quantum wells, surface polaritons or cavity polaritons.

The dielectric mirrors used to form the cavity allow in the fourth chapter an easy introduction of the concept of photonic (or more precisely polaritonic) crystals and ~ bandstructures. This concept will be elucidated with several examples.

The contribution will close with a short conclusion and outlook.