木堆结构光子晶体最佳参量的理论分析

摘要

为了优化3维木堆结构光子晶体的结构参量,采用平面波展开法,从高度和周期之比、填充率、晶格与x轴的夹角3方面理论分析了3维木堆结构光子晶体完全禁带的性质.当填充率在0.25～0.3之间变化时,带隙比变化很小.最佳高度和周期之比为1.3.当晶格与x轴的夹角在40°～50°之间变化时,带隙比超过0.18.当高度和周期之比等于1.3,旋转角度在42°～48°之间变化时,最大带隙比为0.2保持不变.结果表明,3维木堆结构光子晶体的结构参量调节范围比较宽.这一结果为实验室制备带来方便.%In order to optimize the structure parameters of 3-D woodpile-type photonic crystals,based on the plane-wave method,the property of complete forbidden bands of woodpile structure was theoretically studied in terms of varying aspect height-to-pitch ratios,filling fractions,and rotation angles.It was found that the gap to midgap ratio changed slightly with a filling fraction ranging from 0.25 to 0.30.The optimum height-to-pitch ratio was about 1.3.The gap to midgap ratio became larger than 0.18 when the rotation angle changed from 40° to 50° and the maximum gap to midgap ratio of 0.2 remained unchanged for the rotation angle ranging from 42° to 48° with height-to-pitch ratio of 1.3.The results show this type of woodpile structure can produce big band gaps in a wider parameter range,which offers convenience for preparing three- dimension photonic crystals in laboratory.