Application of Genetic Algorithm to the Design of Omnidirectional Reflectors in Visible Region*
利用遗传算法设计可见光波段全能反射器

A novel application of genetic algorithm (GA) in designing broad omnidirectional reflectors was introduced. The key is to search the best combination style and thickness ratios of different one-dimension (1D) quasi-periodic (QP) photonic crystals (PCs) to form a photonic heterostructure. Using the transmission matrix method (TMM), the transmission properties of electromagnetic wave in 1D QP systems were investigated. Numerical results show that the omnidirectional reflection (ODR) band of 1D QP PCs is effected by the unit cell and period number. Based on these rules, the best combination schemes for heterostructures was found out and two perfect omnidirectional reflectors for application in visible region were obtained. For instance, a high reflector described as (HLLHL)13(HL)13( LHL)15, where nL=1.46, nH=2.6, dL=0.218λ0/nL, and dH=0.201λ0/nH, is achieved to provide ODR bandwidth of 88.42% (446 nm~779 nm) in visible region.