Crystal Optics With Allowance for Spatial Dispersion; Exciton Theory. I

Introduction 323 1. Complex Dielectric Tensor ij (ω, k) and Normal Waves in the Medium 328 a) The Tensor ij (ω, k) and Its Properties 328 b) Normal Electromagnetic Waves in a Medium. Transverse and Longitudinal Waves. "Fictitious" Longitudinal Waves and "Polarization Waves" 331 c) Energy and Other Relations for Waves in an Anisotropic Medium 334 2. The Tensor ij (ω, k) in Crystals 337 a) The Concept of the Tensor ij (ω, k) for Crystals 337 b) The Case of Weak Spatial Dispersion (a/λ ≪ 1) 339 Cited Literature, Part I 345 3. Crystal optics with allowance for spatial dispersion, a) New wave near absorption line in gyrotropic crystals, b) New waves in non-gyrotropic crystals, c) Optical anisotropy of cubic crystals. Quadrupole absorption lines, d) Effect of mechanical stresses and external electric and magnetic fields, e) The problem of boundary conditions, f) Experimental investigations of effects of spatial dispersion in crystal optics. 4. Quantum mechanical calculation of the tensor ij (ω, k). a) Quantum mechanical expression for ij (ω, k). b) Mechanical excitons and the tensor ij (ω, k) in molecular crystals and in the case of the classical oscillator model, c) Absorption mechanism and calculations. Concluding remarks. Cited literature, part II.