光学学报, 2019, 39 (8): 0819001, 网络出版: 2019-08-07
Lieb晶格相对格点强度对异相八极光束传输的影响 下载: 936次
Effect of Relative Lattice Intensity of Lieb Lattice on Propagation of Out-of-Phase Octupole Beam
非线性光学 Lieb晶格 光束传输法 异相八极光束 nonlinear optics Lieb lattice beam propagation method out-of-phase octupole beam
摘要
以最小周期单元包含5个格点的新型Lieb晶格(Lieb-5)为平台,将Lieb-5晶格的格点根据其空间位置分成中心格点和边缘格点,用光束传输法研究具有不同强度值的两组格点对异相八极光束传输的影响。仿真结果表明:无论是采用格点入射还是非格点入射,当中心格点的强度小于边缘格点的强度(两组格点强度为2∶3)时,光束在传输过程中始终保持八峰形状,呈现出强局域性;否则,光束在传播过程中无法始终保持八峰结构,入射格点之间的能量随着传播距离的增加而呈周期性地相互耦合,呈现出一种弱局域性;原因是Lieb-5晶格特有的拓扑结构产生的几何阻挫性能抑制了光束的离散衍射,若晶格的束缚性、光束的衍射效应和异相光束的相互作用达到平衡,则能保持八峰结构,否则光束不能始终保持八峰结构。
Abstract
In the present study, a novel Lieb lattice with five points (hereinafter referred to as the Lieb-5 lattice) in the minimum periodic unit is used as a platform. The sites of Lieb-5 lattices are classified into two categories according to their spatial positions, namely, the center and edge lattices. Using the beam-propagation method, we investigate the effects of different intensities of two sets of lattices on out-of-phase octupole-beam propagation. The ratio of the intensities of the two lattice categories is 2∶3; further, according to simulation results for either an on-site or off-site incident, when the intensity of the center lattice is less than that of the edge lattice, as in this case, an eight-peak shape with strong localization is maintained during beam propagation. Otherwise, the beam barely maintains the shape of the eight peaks in the propagation process. The energy between the incident lattices is periodically coupled with the increase of propagation distance, presenting weak localization, because the geometric frustration of the Lieb-5 lattice caused by its unique topological structure inhibits the discrete diffraction of light beams. If the binding property of the lattices, diffraction of the beam, and interaction of the out-of-phase beam stay in balance, the eight-peak structure can be maintained; otherwise, the beam cannot always maintain the eight-peak structure.
章晓伟, 覃亚丽, 任宏亮, 薛林林. Lieb晶格相对格点强度对异相八极光束传输的影响[J]. 光学学报, 2019, 39(8): 0819001. Xiaowei Zhang, Yali Qin, Hongliang Ren, Linlin Xue. Effect of Relative Lattice Intensity of Lieb Lattice on Propagation of Out-of-Phase Octupole Beam[J]. Acta Optica Sinica, 2019, 39(8): 0819001.