光诱导准一维光子晶格中离散空间光孤子的相互作用

基于分步束传播法数值分析了离散空间光孤子在准一维光诱 导光子晶格中的相干与非相干相互作用过程. 结果表明: 对于相干孤子, 同相时相互吸引, 反相时相互排斥. 然而, 由于非线性响应的各向异性, 横向排布的非相干孤子会因间隔波导数目的增加而由相互吸引变为相互排斥. 并且, 沿对角方向排布的两个非相干孤子在孤子相 互作用力和布拉格反射的共同影响下, 会呈现出"钟摆式"振荡传输现象. 研究结果有助于进一步理解非线性各向异性对离散孤子相互作用的影响机制, 并为后续实验研究提供理论参考.     

The interaction of in-band and in-gap lattice soliton trains in optically induced two-dimensional photonic lattices

We demonstrate the coherent interactions of lattice soliton trains,including in-band solitons (IBSs) and gap soliton trains (GSTs),in optically induced two-dimensional photonic lattices with self-defocusing nonlinearity.It is revealed that the π-staggered phase structures of the lattice soliton trains will lead to anomalous interactions.Solely by changing their initial separations,the transition between attractive and repulsive interaction forces or reversion of the energy transfer can be obtained.The 'negative refraction' effect of the soliton trains on the interaction is also discussed.Moreover,two interacting IBSs can merge into one GST when attraction or energy transfer happens.     

Coherent and Incoherent Interactions between Discrete-Soliton Trains in Two-Dimensional Light-Induced Photonic Lattices

The coherent and incoherent interactions between discrete-soliton trains are numerically investigated in lightinduced two-dimensional photonic lattices. The solutions of discrete-soliton trains for diamond and square lattices are obtained by Petviashvili iteration method. It is found that for both the kinds of lattices, two in-phase （out- of-phase） discrete-soliton trains attract （repel） each other, and the intermediates are always accompanied with energy transfer. While the interaction forces between two incoherent discrete-soliton trains are always attractive.     

Interaction of in-band and in-gap lattice soliton trains in optically induced two-dimensional photonic lattices

We demonstrate the coherent interactions of lattice soliton trains, including in-band solitons (IBSs) and gap soliton trains (GSTs), in optically induced two-dimensional photonic lattices with self-defocusing nonlinearity. It is revealed that the $\pi$-staggered phase structures of the lattice soliton trains will lead to anomalous interactions. Solely by changing their initial separations, the transition between attractive and repulsive interaction forces or reversion of the energy transfer can be obtained. The `negative refraction' effect of the soliton trains on the interaction is also discussed. Moreover, two interacting IBSs can merge into one GST when attraction or energy transfer happens.     

Incoherent interaction between one- and two-dimensional solitons in noncentrosymmetric photorefractive media

The incoherent interaction between solitons with different transverse dimensions in a noncentrosymmetric photorefractive crystal is studied both in theory and in experiment. An anomalous incoherent interaction between one- and two-dimensional solitons, whose attractive and repulsive effects depend on the soliton separation, is numerically demonstrated by employing an anisotropic model. By launching a one-dimensional green beam and a two-dimensional red beam into a biased SBN:60 crystal, the hybrid-dimensional soliton interaction is performed. The experimental results are in good agreement with the numerical ones.     

基于布里渊区谱的二维光子晶格线性缺陷模式分析

结合均匀光子晶格的衍射关系和晶格中正负缺陷的布里渊区谱特性,探讨了光诱导二维光子晶格中线性缺陷模式的形成条件,对布里渊区中各点的缺陷模式进行了模拟分析,并得到了光子带隙结构中“嵌入点”X₁点的正、负缺陷模式.结果表明：对于二维缺陷,只有当衍射关系曲面中沿两个正交的横向波矢方向同时为正常（反常）衍射的区域才能存在正（负）缺陷模式;而对于一维缺陷,只要在一个横向波矢方向上存在正常（反常）衍射的区域就可以支持正（负）缺陷模式,因此在某些特殊点处,正和负的缺陷模式可以同时存在.X₁点正缺陷模式的存在预示着自聚焦非线性同样可以支持带内孤子.研究结果有助于对光子晶格中晶格孤子（特别是带内孤子）的理解和进一步研究. 关键词： 光诱导光子晶格 光子带隙 线性缺陷态     

光诱导平面波导阵列中离散空间光孤子的相干相互作用

采用Petviashvili迭代法对光诱导平面波导阵列中的一维离散空间光孤子进行求解,利用分步束传播法对离散空间光孤子间的相干相互作用进行了详细的数值模拟.探讨了离散孤子间的相位差、孤子光强、波导阵列写入光的强度和周期以及外加电场对相互作用过程的影响.结果表明：离散孤子间的相位差对相互作用的影响与连续介质中的情况类似,不同相位差情况下的相互作用也表现为吸引、排斥以及能量转移等现象.同时,离散孤子间的相干相互作用过程(如融合距离和排斥间距等)均会受到孤子光强、波导阵列写入光的强度和周期以及外加电场大小的影响 关键词： 光诱导平面波导阵列 离散空间光孤子 相干相互作用     

Solitary Wave Evolution of Optical Planar Vortices in Self-Defocusing Photorefractive Media

Solitary wave evolution of optical planar vortices in isotropie self-defoeusing photorefractive media is investigated in detail. We demonstrate that the formation of a planar vortex soliton intensively depends on the diameter and maximum intensity of the input vortex Seam. The exact solutions of planar vortex solitons are obtained due to the Petviashvili iteration method. It is found that, with the increasing soliton maximum intensity, the soliton core will be gradually diminished to a minimum value.     

紧聚焦角向矢量光激发下硅环-开口金环纳米天线的单向散射

采用时域有限差分法,数值研究了紧聚焦角向矢量光激发下硅环-开口金环纳米天线的远场散射特性.结果表明:紧聚焦的角向矢量光可在硅纳米环和开口金纳米环中分别激发出不同峰宽的磁偶极模式;由于模式间的杂化效应,两种磁偶极模式会耦合形成硅环-开口金环纳米结构的反键和成键模式;在峰谷1064 nm波长处,反键和成键模式间的相消干涉在面内形成了单向远场散射.进一步,详细研究了几何参数对单向散射的影响,并且借助该纳米天线的单向散射特性,实现了偶极光源的定向发射.研究结果提供了一种纳米光子结构远场散射的灵活调控手段,并有望为纳米光源、光学传感器等的设计和研发提供有益的参考.     

基于等离激元法布里-珀罗腔折射率测量的实验设计

利用自下而上的纳米加工工艺,制备了一种由银纳米线对和金膜构成的等离激元法布里珀罗(F-P)腔。暗场散射光谱和数值模拟表明,金膜表面传输的表面等离激元经银纳米线对的多次反射下,会在腔内形成驻波现象,并在散射光谱中呈现出多光束干涉调制的光谱线型。利用这一原理设计一个折射率测量实验,通过测量不同浓度甘油溶液的折射率,得到了F-P腔共振波长随溶液折射率增大的线性红移规律。进而通过调谐F-P腔的长度,得到该F-P腔最高的探测灵敏度为555 nm/RIU。