利用遗传算法设计可见光波段全能反射器

介绍了遗传算法在设计宽频带全能反射器中的应用.设计的关键是通过遗传算法寻找到不同一维准周期光子晶体间的最佳组合方式以及光学厚度以便形成一个光子晶体异质结.利用传输矩阵法分析了一维准周期系统中的电磁传输特性.计算结果表明,准周期光子晶体的全方向反射带宽受晶胞单元以及周期数的影响.根据这些规律,用遗传算法成功地优化了光子晶体异质结的结构并得到两种适用于可见光波段的高性能全能反射器.例如结构为(HLLHL)13(HL)13( LHL)15 ［注: nL=1.46,nH=2.6,dL=0.218λ0/nL且dH=0.201λ0/nH］的反射器在可见光波段内的全方向反射带宽达到了88.42% (446 nm~779 nm).

Application of Genetic Algorithm to the Design of Omnidirectional Reflectors in Visible Region*

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.