Demonstration of wide higher-order stop-bands in two-dimensional photonic crystals using a real-valued genetic algorithm

A real-valued genetic algorithm is used for the realization of higher-order stop-bands in two-dimensional (2D) photonic crystals of square lattice. In this procedure, a number of circular rods are arranged in the unit cell of the crystal. Using a genetic algorithm, we determine the radii and centers of the rods for a maximum stop-band. Three optimized photonic crystal structures are presented. Stability analyses are carried out to determine the dependence of band-gap characteristics on some of the lattice parameters.