ABSTRACT
This chapter introduces the classical electrodynamics that constitutes the basis of modern nanophotonics and plasmonics. It considers the theory of electromagnetic fields in continuous media. The chapter gives an optical description of non-magnetic solids within the local response approximation. It reviews the theory of electromagnetic eigenwaves in solids. In the classical theory, the concept of electromagnetic field is introduced to describe how charges interact with each other. Every charge is assumed to generate electromagnetic field, via which it interacts with other charges. In the case of multiple charges, the overall field is given by the sum of corresponding fields generated by every charge, according to the superposition principle. For non-magnetic materials, there are three types of elementary polarization excitations, given by different kinds of polarization charges. In quasi-particle classification, they are: phonons resulting from oscillations of the crystal lattice, excitons appearing due to bound electrons and their inter-band transitions, and plasmons caused by collective oscillation of the conduction electrons.
