Numerical Simulation Study of the Influence of the Bragg Mirror's Optical Properties on the Reflection Spectrum

Abstract

The field of thin films is interesting in the design and manufacture of Bragg mirrors by multilayer, which they must be, sprayed on the substrate on one side only. The working principle of the Bragg mirror is based on the realization at a given wavelength results from the constructive interference of the set of reflections from each mirror interface. The design of a Bragg mirror had based on the schematic formula of the layers, which are adapted to the spectral properties of the chosen mirror. To do this, we have optimized the Bragg mirror's spectral properties by means of numerical simulation, in order to identify the factors, influencing these properties and how, to improve the mirror's reflection. The results obtained show that the increase in the number of pattern the bandwidth decreases and the number of oscillations outside the bandwidth increases. The greater the index contrast between the high index n_H and the low index n_B, the closer the reflection coefficient will be to 1 and the higher the normalized bandwidth width. To obtain a pattern of bilayers with a wide spectral bandwidth, we need to choose a quarter-wave thickness that has not multiplied by λ/4.