光学学报, 2016, 36 (5): 0516003, 网络出版: 2016-05-03
各向异性材料对二维六角晶格光子晶体中狄拉克点的影响
Effect of Anisotropic Materials on Dirac Point in Two-Dimensional Photonic Crystals Arranged in a Hexagonal Lattice
摘要
光子能带结构中的狄拉克点是目前光子晶体研究中新兴的热点。选用双轴材料,用六边形介质柱构成了六角晶格各向异性光子晶体。该光子晶体有三个各异的主介电常数 εxx、εyy、εzz。依据麦克斯韦方程组,垂直极化(TE)波中的狄拉克点会受到 εxx≠εyy的影响,即可以通过调制双轴材料中X、Y方向的主折射率Nx、Ny得到光子晶体中TE波的狄拉克速率,从而调节TE波中狄拉克点在能带结构图中的位置(即调节狄拉克点的归一化频率及其在布里渊区的位置)。研究了Nx、Ny(对应 εxx、 εyy)与TE波中狄拉克点的存在性的关系,并通过仿真实验验证了提出的观点。这些研究可为研发新型光学器件以及构建光子芯片提供更多的可能。
Abstract
Dirac point in photonic band structures is a research focus in the present photonic crystal field. The hexagonal rods arranged in a hexagonal lattice anisotropic photonic crystals using bi-axial materials are presented. In the photonic crystals, there are three different primary dielectric constants, εxx,εyy and εzz. Based on the Maxwell’s equations, the Dirac point in transverse electric (TE) wave is affected by εxx≠εyy. The Dirac velocity in the TE wave can be obtained by modulating the principal refractive index Nx and Ny in the X and Y directions of bi-axial materials, and thus the position of the Dirac point in the energy band structure can be changed by adgusting TE wave. That is to say, the normalized frequency of the Dirac point and its position in the Brillouin zone can be changed. The relationship between Nx, Ny (corresponding to εxx, εyy) and existence of the Dirac point in TE wave is studied, and the proposed opinion is demonstrated by simulation experiments. The characteristics will provide more possibility for the design of novel photonic components and photonic chip architectures.
温菲, 谢康, 张维. 各向异性材料对二维六角晶格光子晶体中狄拉克点的影响[J]. 光学学报, 2016, 36(5): 0516003. Wen Fei, Xie Kang, Zhang Wei. Effect of Anisotropic Materials on Dirac Point in Two-Dimensional Photonic Crystals Arranged in a Hexagonal Lattice[J]. Acta Optica Sinica, 2016, 36(5): 0516003.