共查询到19条相似文献,搜索用时 62 毫秒
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利用解析和数值方法研究了在具有横向折射率周期性调制的克尔型非线性介质中光学格子孤子的传输,得到了孤子参数的演化方程以及格子孤子的形成和稳定传输的条件.结果表明:当光束的入射角小于某临界角度时,光束可被类似波导形式的路径俘获而稳定传输,该临界角随折射率调制周期、调制深度的增加而增大,且光束越窄临界值越大.此外,线性空间啁啾虽然对光束传输的中心位置没有任何影响,但会导致光束发散从而破坏格子孤子的形成和稳定传输,对此提出了采用特定功率取值来补偿啁啾作用从而形成格子孤子的方案.
关键词:
光孤子
光学格子
光传输
矩方法 相似文献
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基于无偏压光伏光折变晶体,理论研究了热电效应和光伏效应共同作用下的稳态空间孤子对.从非相干耦合波方程出发,推导了热电光伏孤子对的数值解;采用有限差分方法,数值模拟了各类孤子对的强度包络.结果表明:在自散焦光伏光折变晶体中,当正的热电场远大于光伏场时,亮-亮孤子对可以存在;当暗-暗或者灰-灰孤子对存在时,负的热电场可以增强自散焦效应,进而减小孤子的半峰全宽.各类孤子对的半峰全宽可以通过改变热电场的大小而加以操控.此外,非相干耦合热电光伏孤子对可以在一定条件下分别退化成热电孤子对或者光伏孤子对.借助晶体的热电效应,可以使光折变晶体LiNbO3从自散焦转变成自聚焦,从而灵活控制晶体中孤子对的特性. 相似文献
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We study the quantum phase transition of ultracold atoms in the honeycomb optical lattice. The Hamiltonian of ultracold bosonic atoms in the honeycomb optical lattice is derived. We take the mean-field approximation and further solve the Hamiltonian with the numerical diagonalization method. We obtain the phase diagram and find that the Mort-insulator (MI), density wave (DW) and modulated superfluid (MS) phases appear. Furthermore, the phase diagram is analyzed according to the order parameter and the average number of particles. 相似文献
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光子晶格作为一种光学周期性离散体系,具有通常均匀介质所无法比拟的独特性质,它为空间离散孤子、表面波以及衍射操控等一系列线性和非线性离散动力学行为的实验观测提供了便利条件,同时在全光路由、全光开关和光子计算机等方面具有重要的应用前景.文章简要回顾了南开大学的研究小组近期在二维光子晶格中有关空间带隙孤子的一系列研究工作,包括二维基本带隙孤子、类偶极带隙孤子、带隙孤子串以及涡旋带隙孤子等.在有的实验过程中,文章作者清晰地观测到探测光束的频谱整形,波常数从具有反常衍射的导带底部演化到光子禁带中,并且通过干涉图反映 相似文献
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为了让温度传感器在集成化全光控制中找到实现途径,提出一种基于非局域空间光孤子传输的温度传感器的理论方案.以铅玻璃作为非局域空间光孤子的传输介质,通过研究圆柱形铅玻璃中, 中心入射光束在传输过程中的相移问题, 得出在环境温度0.32 ℃的改变就可以引起孤子π相移的结论.此温度改变对相移的调制有望为基于干涉仪原理的温度传感器提供一个可行且灵敏度较高的实现方案. 相似文献
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We study the topological properties of spin-orbit coupled s-wave superconductor in one-dimensional optical lattice. Compared to its corresponding continuum model, the single particle spectrum is modified by the optical lattice and the topological phase which is characterized by the Majorana edge modes can survive in two regions of the singleparticle spectrum. With the help of the self-consistent Bogoliubov-de Gennes calculation in the harmonic trap, we find that the existence of an upper critical magnetic field removes the topological superconductor phase to the trap wings.We also study the effects of nonmagnetic and magnetic impurity on the topological properties, and find the universal behavior of the mid-gap state induced by impurity in the topological superconductor phase in strong scattering limit. 相似文献
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The Bose-Hubbard model describing interacting bosons in an optical lattice is reduced to a simple spin-1 XY model with single-ion anisotropy in the vicinity of the Mort phase. We propose a mean-field theory based on a constraint SU(3) pseudo-boson representation on the effective model to study the properties of the superfluid-Mott-insulator phase transition. By calculating the elementary excitation spectra and the average particle number tluctuation in the Brillouin zone center, we lind that the energy gaps vanish continuously around (JXY/Jz)c≈ 0.175 and (JxY/Jz)c ≈ 0.094 for 2D and 3D cubic lattices respectively, where the superfluid order parameters come up from zero and the Mort insulator state changes into a superfluid state. 相似文献
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We obtain analytically the static states and corresponding collective-excitation spectra of a quasi-onedimensional spin-1 condensate modulated by a long-wavelength optical lattice in the weak lattice limit. It is demonstrated that both ferromagnetic and antiferromagnetic condensates may exhibit dynamical instability, which agree with the results with numerical simulation. In the homogeneous limit, our results reduce to the previous results for homogeneous spinor condensates, i.e., dynamical instability can occur only for ferromagnetic interaction and an antiferromagnetic condensate is always dynamically stable. 相似文献