A-plane 1 Dielectric layer 1 Dielectric medium 1 Dielectric permittivities 1 Dielectric permittivity 1 Differential equations 1 Diffraction 1 Elastic waves 1 Electromagnetic plane wave 1 Energy gap 1 Gradient refractive index 1 One dimensional 1 One-dimensional 1 Permittivity 1 Photonic band gap 1 Photonic bandgap (PBG) Photonic crystals 1 Plane wave 1 Reflection and transmission coefficients 1 Refractive index 1 Wave propagation 1