Reflectivity analysis of the Bragg reflector based on periodic structures of different thin layers

An analytical model for calculating the reflection and transmission coefficients of a Bragg reflector with periodic structure is derived. Using explicit expressions for these coefficients the reflectivity of the periodic structures for different pairs of layers and layer thickness was simulated. We investigate the reflectivity of the periodic structures consisting of following pairs of successive layers: SiO₂/Si₃N₄ (low ratio of refractive indexest); poly-Si/SiO₂(high ratio), Si/air gap (high contrast). The theoretical and experimental investigations of a particular periodic structure consisting of SiO₂/Au are also presented. Our method allows the rapid evaluation of reflectance of Bragg reflector with periodic structure.