ABSTRACT
This chapter presents the fundamental properties of light as described by Maxwell’s electromagnetic (EM) theory and the laws governing the propagation of light in isotropic materials. It summarizes some of the most often used concepts and expressions such as Maxwell’s equations, wave equation, energy flow, the Poynting vector, irradiance, reflection, refraction, and dispersion. The chapter discusses isotropic and homogeneous materials, and nonconducting materials with linear properties. The phase velocity of light propagating in materials with real relative permittivity and real relative permeability both being simultaneously negative is negative. The phase velocity of an EM wave is described as negative, if it is directed opposite to the power flow given by the time-averaged Poynting vector. The study of diffraction from a negative phase-velocity (NPV) medium is especially important, because all experimental realizations of NPV metamaterials so far are based on periodical structures of composite materials, with size of the unit cell smaller than the wavelength.
