The optimization of large gap-midgap ratio photonic crystal with improved Bisection-Particle Swarm Optimization

Abstract Photonic crystals possessing large gap–midgap ratios are designed using the improved Bisection-Particle Swarm Optimization (BPSO) algorithm and plane-wave expansion method. The optimal gap–midgap ratios of three kinds of photonic crystals, such as ring rods, square rods connected by veins, and rotating square rods, are calculated, and the corresponding geometry parameters are also represented. Compared with the traditional dimension-by-dimension scanning method, the improved BPSO algorithm greatly reduces the computation time, and its accuracy is controllable.