Physical properties of photonic crystals
Photonic crystals and photon gaps - Properties and applications

What happens when a wave coming from a homogeneous medium of index n, linear and isotropic, illuminates a photonic crystal? Many different cases can arise, depending on the characteristics of the incident light (its angle of incidence, polarization and wavelength) and those of the photonic crystal (its symmetry, cutting plane, number of crystal planes, presence of total or partial photonic band gaps, etc.). We'll confine ourselves here to the case of a semi-infinite crystal, without worrying about any transmitted waves, whether evanescent or propagating without attenuation. We will return to the refraction and transmission aspects of photonic crystals in paragraphs ...