填充率对有限高度二维光子晶体带隙的影响

针对三角晶格空气孔和四方晶格介质柱这两种结构的有限高度二维光子晶体，用平面波展开法计算它们在不同填充率下的带隙结构，分析了带隙特性及填充率对带隙结构的影响。结果表明，晶胞中的空气所占的比例较大时，带隙的位置向高频方向移动，带隙宽度则在逐渐增大的同时又受到光锥边界的限制，结构参数为相对介电常数2和12，总高度为3L1；三角和四方晶格的中间层高度分别为L1=0．6a和L1=1.5a时，填充率r／a分别取0．42和0．19可得到较大的带隙，范围分别是(0．30～0．45)和(0．34～0．45)wa／2πc。

Effect of Stuffing Rate on the Band Gap Structure of the Finite Height Photonic Crystals

The effect of stuffing rate on band gap structure of finite height 2-D photonic crystals was investigated.Two kinds of crystal lattices are considered:the triangular lattice with air hole and square lattice with dielectric rod.The 3-D plane wave method is used to calculate the eigen equation.The characteristics of the band gap structure are analyzed.The results shows that while the air included in a unit cell increases,the band gap tends to be in a higher frequency zone and also become wider,and the width of the band gap is also restricted by the light cone.While the dielectric constants are 2 and 12,total height is 3L_1,the heights of the middle layer for triangular and square lattice are L_1=0.6 a and L_1=1.5 a respectively,large band gap can be found at r/a=0.42 for triangular lattice and r/a=0.19 for square lattice.