A computational approach for engineering optical properties of multilayer thin films: Particle swarm optimization applied to Bruggeman homogenization formalism

An algorithm based on Particle Swarm Optimization (PSO) and Bruggeman Homogenization Formalism was presented to design a model structure for a thin film with various sublayers to obtain a desired optical reflectance/transmittance spectrum. In principle, the results showed that the designed structure is strongly affected by the input parameters of the algorithm such as film thickness, number of sublayers, incident light characteristic wavelength and utilized materials, and the method has its ability to find the best optimized structure based on desired optical properties. The results of calculations were in good agreement with the physical principles of classical optics and the method could be useful in both design and characterization purposes.