一维光子晶体中多负折射率缺陷导致的缺陷模

Defect Modes Based on Negative Refractive Index Structural Defects Coupled in One-dimensional Photonic Crystals

利用传输矩阵方法研究了多个周期性分布的负折射率缺陷的一维光子晶体的透射谱.以32个周期的1/4波堆存在5个负折射率缺陷的光子晶体为例进行了数值计算.结果表明:在带隙中产生多个缺陷模,这些缺陷模的分布依赖于缺陷在晶体中的分布.当缺陷密集时,缺陷耦合较强,缺陷模相距较远;当缺陷稀疏时,缺陷耦合较弱,缺陷模相距较近,分立的缺陷模趋于简并,由此形成一个很窄的通带.与正折射率缺陷情形相比较,负折射率缺陷间的相互作用对缺陷模的影响更大,缺陷模谱线也更宽.

The transmission through one -dimensional photonic crystals with a number of negative refractive index structural defects are studied by using transfer - matrix - method. Quarter - wave stack of 32 periods with five half - wave negative refractive index structural defects is taken as an sample for numerical calculation. The result shows that some defect modes occur in the photonic band gap , and the distribution of these defect modes depends on the distribution of these defects in the photonic crystal. When the separation of the defects is small, the defect modes are coupled each other strongly, so the separation between defect modes is large. When the separation of the defects is large, the defect modes are coupled each other weakly, so the discrete defect modes tend to be close each other and a narrow pass band is formed. Compared with the case of positive refractive index structural defects, the influence of the interaction between negative refractive index structural defects on defect modes is stronger, the spectrum - width of defect mode is broader.