二维介质柱正方复合周期结构光子晶体的禁带研究

一种介质柱在空气中复合周期排列的二维光子晶体新结构被提出和研究，该结构是二套不同尺寸的介质柱的正方周期排列的叠加所构成。针对这种光子晶体，我们对Maxwell方程做出了严格的Fourier变换，从而建立了快速的平面波展开算法。应用所建立的快速理论算法，我们详细地数值分析了这种光子晶体的能带结构及相关禁带，结果表明，与介质柱的简单正方周期结构相比，复合周期结构由于降低了结构的对称性，它的绝对禁带得到了显著的增大。

Band gaps in two-dimensional photonic crystals with composite square-lattices of dielectric columns

A two-dimensional photonic crystal consisting of two square arrays of square dielectric columns with different sizes in air is proposed and investigated theoretically. For the proposed structure, Maxwell’s equations are Fourier transformed rigorously, and a plane-wave expansion method with fast convergence is then formulated. With this method, the band structure of the photonic crystal is numerically analyzed carefully. It is shown that compared with the related structure with a single square lattice, the absolute band gap of the proposed structure is remarkably increased after optimizing the geometric parameters, owing to the decrease of the structural symmetries.