共查询到20条相似文献,搜索用时 31 毫秒
1.
We investigate the existence and stability of different families of spatial solitons in optical waveguide arrays whose amplitudes obey a disordered distribution. The competition between focusing nonlinearity and linearly disordered refractive index modulation results in the formation of spatial localized nonlinear states. Solitons originating from Anderson modes with few nodes are robust during propagation. While multi-peaked solitons with in-phase neighboring components are completely unstable, multipole-mode solitons whose neighboring components are out-of-phase can propagate stably in wide parameter regions provided that their power exceeds a critical value. Our findings, thus, provide the first example of stable higher-order nonlinear states in disordered systems. 相似文献
2.
Y. Tan F. Chen P. P. Beli?ev M. Stepi? A. Maluckov C. E. Rüter D. Kip 《Applied physics. B, Lasers and optics》2009,95(3):531-535
Photovoltaic photorefractive binary waveguide arrays are fabricated by proton implantation and selective light illumination
on top of an iron-doped near stoichiometric lithium niobate crystal. Linear discrete diffraction and nonlinear formation of
gap solitons were investigated by single-channel excitation using Gaussian light beams coupled into either wide or narrow
waveguide channels. The results show that, at low power, linear light propagation leads to discrete diffraction, whilst for
higher input power the focusing mechanism dominates, finally leading to the formation of gap solitons in the binary waveguide
arrays. Our simulation of light propagation based on a nonlinear beam propagation method confirms the experimental findings. 相似文献
3.
4.
F. Setzpfandt D. N. Neshev A. A. Sukhorukov R. Schiek R. Ricken Y. Min Y. S. Kivshar W. Sohler F. Lederer A. T��nnermann T. Pertsch 《Applied physics. B, Lasers and optics》2011,104(3):487-493
We present theoretical and experimental studies on nonlinear beam propagation in lithium niobate waveguide arrays utilizing higher-order second harmonic bands. We find that the implementation of the higher-order second harmonic bands leads to a number of new effects. The combined interaction of two second harmonic bands with a propagating fundamental beam can lead to a complete inhibition of nonlinear effects or to the formation of discrete spatial solitons, depending only on the wavelength of the fundamental wave. Furthermore we analyze the properties of discrete solitons, allowing for linear coupling of the second harmonic. Here we predict and demonstrate experimentally a power dependent phase transition of the soliton topology. 相似文献
5.
We analyze stability and generation of discrete gap solitons in weakly coupled optical waveguides. We demonstrate how both stable and unstable solitons can be observed experimentally in the engineered binary waveguide arrays and also reveal a connection between the gap-soliton instabilities and limitations on the mutual beam focusing in periodic photonic structures. 相似文献
6.
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 相似文献
7.
We study analytically and numerically an optical analogue of Dirac solitons in binary waveguide arrays in the presence of Kerr nonlinearity. Pseudo-relativistic soliton solutions of the coupled-mode equations describing dynamics in the array are analytically derived. We demonstrate that with the found soliton solutions, the coupled mode equations can be converted into the nonlinear relativistic 1D Dirac equation. This paves the way for using binary waveguide arrays as a classical simulator of quantum nonlinear effects arising from the Dirac equation, something that is thought to be impossible to achieve in conventional (i.e. linear) quantum field theory. 相似文献
8.
We observe experimentally higher-order solitons in waveguide arrays with defocusing saturable nonlinearity. Such solitons can comprise several in-phase bright spots and are stable above a critical power threshold. We elucidate the impact of the nonlinearity saturation on the domains of existence and stability of the observed complex soliton states. 相似文献
9.
Desyatnikov AS Neshev D Ostrovskaya EA Kivshar YS Krolikowski W Luther-Davies B García-Ripoll JJ Pérez-García VM 《Optics letters》2001,26(7):435-437
We introduce the concept of multipole spatial optical vector solitons associated with higher-order guided modes trapped by a soliton-induced waveguide in a bulk medium. Such stationary localized waves include previously predicted vortex- and dipole-mode vector solitons and also describe new higher-order vector solitons and necklace-type beams. We present the theoretical and experimental results of the structure, formation, and instability development of the quadrupole vector solitons. 相似文献
10.
《Physics letters. A》2020,384(25):126625
We propose a mechanism for realising a unidirectional flow of discrete solitons in optical waveguide arrays. Modulating the nonlinear interaction strength in each waveguide according to a double reflectionless potential well with slight difference in the depths of its two wells, we achieve a unidirectional flow of the soliton propagation. We verify clearly, through the transport coefficients as in terms of the speed of the incident soliton, that an incident soliton velocity window of finite width exists where unidirectional flow can be realised. We discuss the physics underlying this behaviour on the basis of energy exchange between the soliton's kinetic and interaction energies. 相似文献
11.
Ci-bo LOU Li-qin TANG Dao-hong SONG Xiao-sheng WANG Jing-jun XU Zhi-gang CHEN 《Frontiers of Physics in China》2008,3(1):1-12
The study of wave propagation in periodic systems is at the frontiers of physics, from fluids to condensed matter physics,
and from photonic crystals to Bose-Einstein condensates. In optics, a typical example of periodic system is a closely-spaced
waveguide array, in which collective behavior of wave propagation exhibits many intriguing phenomena that have no counterpart
in homogeneous media. Even in a linear waveguide array, the diffraction property of a light beam changes due to evanescent
coupling between nearby waveguide sites, leading to normal and anomalous discrete diffraction. In a nonlinear waveguide array,
a balance between diffraction and self-action gives rise to novel localized states such as spatial “discrete solitons” in
the semi-infinite (or total-internal-reflection) gap or spatial “gap solitons” in the Bragg reflection gaps. Recently, in
a series of experiments, we have “fabricated” closely-spaced waveguide arrays (photonic lattices) by optical induction. Such
photonic structures have attracted great interest due to their novel physics, link to photonic crystals, as well as potential
applications in optical switching and navigation. In this review article, we present a brief overview on our experimental
demonstrations of a number of novel spatial soliton phenomena in light-induced photonic bandgap structures, including self-trapping
of fundamental discrete solitons and more sophisticated lattice gap solitons. Much of our work has direct impact on the study
of similar discrete phenomena in systems beyond optics, including sound waves, water waves, and matter waves (Bose-Einstein
condensates) propagating in periodic potentials.
相似文献
12.
LOU Ci-bo TANG Li-qin SONG Dao-hong WANG Xiao-sheng XU Jing-jun CHEN Zhi-gang 《Frontiers of Physics》2008,3(1):1
The study of wave propagation in periodic systems is at the frontiers of physics, from fluids to condensed matter physics, and from photonic crystals to Bose-Einstein condensates. In optics, a typical example of periodic system is a closely-spaced waveguide array, in which collective behavior of wave propagation exhibits many intriguing phenomena that have no counterpart in homogeneous media. Even in a linear waveguide array, the diffraction property of a light beam changes due to evanescent coupling between nearby waveguide sites, leading to normal and anomalous discrete diffraction. In a nonlinear waveguide array, a balance between diffraction and self-action gives rise to novel localized states such as spatial “discrete solitons” in the semi-infinite (or total-internal-reflection) gap or spatial “gap solitons” in the Bragg reflection gaps. Recently, in a series of experiments, we have “fabricated” closely-spaced waveguide arrays (photonic lattices) by optical induction. Such photonic structures have attracted great interest due to their novel physics, link to photonic crystals, as well as potential applications in optical switching and navigation. In this review article, we present a brief overview on our experimental demonstrations of a number of novel spatial soliton phenomena in light-induced photonic bandgap structures, including self-trapping of fundamental discrete solitons and more sophisticated lattice gap solitons. Much of our work has direct impact on the study of similar discrete phenomena in systems beyond optics, including sound waves, water waves, and matter waves (Bose-Einstein condensates) propagating in periodic potentials. 相似文献
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14.
Morandotti R Mandelik D Silberberg Y Aitchison JS Sorel M Christodoulides DN Sukhorukov AA Kivshar YS 《Optics letters》2004,29(24):2890-2892
We report an experimental study of discrete gap solitons in binary arrays of optical waveguides. We observe self-focusing indicating soliton generation when the inclination angle of an input beam is slightly above the Bragg angle and show that the propagation direction of the emerging gap soliton is influenced by the effect of interband momentum exchange. 相似文献
15.
We analyze discrete surface modes in semi-infinite binary waveguide arrays, which can support simultaneously two types of discrete solitons. We demonstrate that the analysis of linear surface states in such arrays provides important information about the existence of nonlinear surface modes and their properties. We find numerically the families of both discrete surface solitons and nonlinear Tamm (gap) states and study their stability properties. 相似文献
16.
In this paper, by virtue of symbolic computation, the investigation is made on a generalized variable-coefficient higher-order nonlinear Schrödinger equation with varying higher-order effects and gain or loss, which can describe the femtosecond optical pulse propagation in a monomode dielectric waveguide. A modified dependent variable transformation is introduced into the bilinear method to transform such an equation into a variable-coefficient bilinear form. Based on the formal parameter expansion technique, the multi-soliton solutions of this equation are obtained through the bilinear form under sets of parametric constraints. A Bäcklund transformation in bilinear form is also obtained for the first time in this paper. Finally, discussions on the analytic soliton solutions are given and various propagation situations are illustrated. 相似文献
17.
We suggest a novel concept of diffraction management in waveguide arrays and predict the existence of discrete gap solitons that possess the properties of both conventional discrete and Bragg grating solitons. We demonstrate that one can control both the soliton velocity and the propagation direction by varying the input light intensity. 相似文献
18.
Khomeriki R 《Physical review letters》2004,92(6):063905
The effect of nonlinear transmission in coupled optical waveguide arrays is theoretically investigated and a realistic experimental setup is suggested. The beam is injected in a single boundary waveguide, linear refractive index of which (n(0)) is larger than refractive indexes (n) of other identical waveguides in the array. Particularly, the effect holds if omega(n(0)-n)/c>2Q, where Q is a linear coupling constant between array waveguides, omega is a carrier wave frequency, and c is a light velocity. Numerical experiments show that the energy transfers from the boundary waveguide to the waveguide array above a certain threshold intensity of the injected beam. This effect is due to the creation and the propagation of gap solitons in full analogy with a similar phenomenon in sine-Gordon lattice [Phys. Rev. Lett. 89, 134102 (2002)]]. 相似文献
19.
Topological edge solitons represent a significant research topic in the nonlinear topological photonics. They maintain their profiles during propagation, due to the joint action of lattice potential and nonlinearity, and at the same time are immune to defects or disorders, thanks to the topological protection. In the past few years topological edge solitons were reported in systems composed of helical waveguide arrays, in which the time-reversal symmetry is effectively broken. Very recently, topological valley Hall edge solitons have been demonstrated in straight waveguide arrays with the time-reversal symmetry preserved. However, these were scalar solitary structures. Here, for the first time, we report vector valley Hall edge solitons in straight waveguide arrays arranged according to the photonic lattice with innate type-II Dirac cones, which is different from the traditional photonic lattices with type-I Dirac cones such as honeycomb lattice. This comes about because the valley Hall edge state can possess both negative and positive dispersions, which allows the mixing of two different edge states into a vector soliton. Our results not only provide a novel avenue for manipulating topological edge states in the nonlinear regime, but also enlighten relevant research based on the lattices with type-II Dirac cones. 相似文献
20.
《中国物理 B》2015,(7)
Compression and stretching of ring-vortex solitons, which is a novel self-similar solution of(2+1)-dimensional diffraction decreasing waveguide, is investigated analytically and numerically. We obtain the ring-vortex solitons via the similarity transformation method. The distance modulation for the width, the diffraction, and the nonlinear response, strongly affects the form and the behavior of the self-similar vortex, and facilitates the efficient compression of optical waves. This approximate ring-vortex solitons can reflect the real properties of self-similar optical vortex beams during propagation under certain parameter window selection. Specific examples and figures are given to illustrate discussed features. The results obtained in this paper may have potential values for all-optical data-processing schemes and the design of beam compressors and amplifiers. 相似文献