The finite difference time domain method was used to calculate the transmission characteristics of 2-D super-lattice photonic crystal formed by cylinders and elliptic rods or cylinders and composite medium rods. It is shown that the width of the band gap becomes lager and the central frequency becomes higher with increase of the sectional area of elliptical rods for the cylinder-elliptical rods super-lattice. As to the case of composite medium rods super-lattice, the thicker the nested elliptical rod, the narrower the band gap is and the lower the central frequency is when the long axis is along the direction of incident wave. However, the wider band gap appeared in the range of high frequency band and in the low frequency band the band gap vanished when the long axis direction is perpendicular to the incident wave. The study provides the theory of the manufacture of photonic crystals.%为了研究超晶格结构对光子晶体禁带的影响,应用时域有限差分法对圆/椭圆、圆/复合柱超晶格结构光子晶体的传输特性进行了计算,得到了相应的透射谱.结果表明,对圆/椭圆超晶格,禁带宽度随椭圆柱截面积的增大而变宽,中心频率变大;对于圆/复合柱超晶格结构,椭圆柱内接于圆孔时,禁带宽度随截面积的增大而变窄,中心频率变小;当长轴垂直入射波方向时,高频段出现较宽禁带,低频禁带完全消失;而椭圆孔中内嵌圆柱时,禁带宽度变化与前者相反.该研究为光子晶体器件的制作提供了理论依据.
展开▼
