Grey spatial solitons due to two-photon photorefractive effect

This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and undcr appropriate external bias conditions, it obtains the grey spatial soliton solutions of the optical wave evolution equation. The intensity profile, phase distribution, and transverse velocity of these grey solitons are discussed.

Effects of temperature on screening bright-dark the stability of separate spatial soliton pair

We investigate theoretically the temperature effects on the evolution and stability of a separate screening brightdark soliton pair formed in a serial non-photovoltaic photorefractive crystal circuit. Our numerical results show that, for a stable bright-dark soliton pair originally formed in a crystal circuit at given temperatures, when one crystal temperature changes, the soliton supported by the other crystal will evolve into another stable soliton if the temperature change is quite small, whereas it will become unstable and experience larger cycles of compression or break up into beam filaments if the temperature difference is big enough. The dark soliton is more sensitive to the temperature change than the bright one.

The solutions of the strongly nonlocal spatial solitons with several types of nonlocal response functions

The fundamental and second order strongly nonlocal solitons of the nonlocal nonlinear Schrodinger equation for several types of nonlocal responses are calculated by Ritz＇s variational method. For a specific type of nonlocal response, the solutions of the strongly nonlocal solitons with the same beam width but different degrees of nonlocality are identical except for an amplitude factor. For a nonlocal case where the nonlocal response function decays in direct proportion to the mth power of the distance near the source point, the power and the phase constant of the strongly nonlocal soliton are in inverse proportion to the （m ＋ 2）th power of its beam width.

Spatial weak-light ring soliton in self-assembled quantum dots

By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum dots. It is found that this system can exhibit the transparency, and the width of the transparency window becomes wider with the increase of control light field. Interestingly, a weak probe light beam can form spatial weak-light dark solitons. When it propagates along the axial direction, the soliton will transform into a steady spatial weak-light ring dark soltion. In addition, the stability of two-dimensional spatial optical solitons is testified numerically.

Dark incoherent spatial solitons in logarithmically saturable nonlinear media

This paper studies numerically the dark incoherent spatial solitons propagating in logarithmically saturable nonlinear media by using a coherent density approach and a split-step Fourier approach for the first time. Under odd and even initial conditions, a soliton triplet and a doublet are obtained respectively for given parameters. Simultaneously, coherence properties associated with the soliton triplet and doublet are discussed. In addition, if the values of the parameters are properly chosen, five and four splittings from the input dark incoherent spatial solitons can also form. Lastly, the grayness of the soliton triplet and that of the doublet are studied, in detail.

Evolution and stability of spatial solitons in a photorefractive two-wave mixing system

The dynamical evolution and stability of bright dissipative holographic solitons in biased photorefractive materials in which the self-trapping beam obtains a gain from the pump beam via two-wave mixing has been investigated numerically. Results show that these solitons are stable relative to small perturbations. Adjusting some system parameters, such as the bias field and the angle between beams, can easily control the generation of such solitons. Potential applications in optical switches or repeaters are discussed.

The (1+1)-dimensional spatial solitons in media with weak nonlinear nonlocality

We study the propagation of （l＋l）-dimensional spatial soliton in a nonlocal Kerr-type medium with weak non- locality. First, we show that an equation for describing the soliton propagation in weak nonlocality is a nonlinear Schr6dinger equation with perturbation terms. Then, an approximate analytical solution of the equation is found by the perturbation method. We also find some interesting properties of the intensity profiles of the soliton.

Large phase shift of spatial soliton in lead glass by cross-phase modulation in pump-signal geometry

We investigate the co-propagation of a strong pump beam and a weak signal beam in lead glass, and find that the large phase shift of the strongly nonlocal spatial optical soliton （SNSOS） can be realized via cross-phase modulation. The theoretical study suggests a synchronous propagation of the pump SNSOS and the signal SNSOS under the required initial condition. A π-phase shift of the signal SNSOS is experimentally obtained by changing the power of the pump SNSOS by about 13 mW around the soliton critical power, which agrees qualitatively with our theoretical prediction. The ratio of the phase shift rate of the signal SNSOS to that of the pump SNSOS shows a close match to the reciprocal of the ratio between their wavelengths.

All-Optical EXOR for Cryptographic Application Based on Spatial Solitons

The purpose of this paper is to present an all-optical EXOR for cryptographic application based on spatial soliton beams. The device is based on the propagation and interactions properties of spatial soliton in a Kerr nonlinear material. The interaction force between parallel soliton beam is analyzed from the analytical point of view and an exact solution is presented.

Self-Similar Hermite-Gaussian Spatial Solitons in Two-Dimensional Nonlocal Nonlinear Media

We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained involvinghigher-order Hermite-Gaussian functions. Our theoretical predictions provide new insights into the low-energy spatialsoliton transmission with high fidelity.

Evolution of Dark Spatial Soliton in Quasi-phase-matched Quadratic Media

We theoretically investigate the evolvement of dark spatial soliton with cascading quadratic nonlinearity in quasi-phase-matched second harmonic generation. It is shown that the dark solitary wave can propagate stably when background intensity is large enough, in which diffraction of beam can be balanced by the cascading quadratic nonlinearity. We also analyze the influence of phase-mismatch on the stability of dark soliton propagation.

Nonlocal Optical Spatial Soliton with a Non-parabolic Symmetry and Real-valued Convolution Response Kernel

基于非线性、非抛物线的对称反应的图画，即， Δn 2(I)≈ ρ (0+a1 x-a 2 我们建议的 x 2), 为非局部的空间 soliton 的横过的横梁紧张分发的一个模型。在这个模型，作为有非抛物线的对称的卷绕旋转回答， Δn 2(I)≈ ρ (b 0+b1 f-b 2 有 b 2/b1】 的 f 2 0 被假定。而不是波浪函数 ψ ，而且，为横梁紧张分发 f 的高顺序的非线性的方程被导出，有信封形式的塑造钟的 soliton 解决方案被获得了。结果证明自从非抛物线的反应的术语的存在，非局部的空间 soliton 有双稳态的州的答案。如果波浪数字 β 的频率移动满足 0 【 4 (β -ρb 0/μ)【 3 η 0/8α, 双稳态的州的 soliton 答案对不安是稳定的。从一个抛物线对称的反应核产生的 soliton 答案是小的，这应该被强调。为双稳态的州的 soliton 答案 b 2/b1】 的存在的足够的条件 0 被表明了。

Collisions of Two Spatial Solitons in Inhomogeneous Nonlinear Media

Collisions of spatial solitons occurring in the nonlinear Schringer equation with harmonic potential arestudied,using conservation laws and the split-step Fourier method.We find an analytical solution for the separationdistance between the spatial solitons in an inhomogeneous nonlinear medium when the light beam is self-trapped inthe transverse dimension.In the self-focusing nonlinear media the spatial solitons can be transmitted stably,and theinteraction between spatial solitons is enhanced due to the linear focusing effect (and also diminished for the lineardefocusing effect).In the seff-defocusing nonlinear media,in the absence of seff-trapping or in the presence of linearself-defocusing,no transmission of stable spatial solitons is possible.However,in such media the linear focusing effectcan be exactly compensated,and the spatial solitons can propagate through.

Two-Dimensional Spatial Solitons in Nematic Liquid Crystals

我们在 nematic 液体晶体学习空间 solitons 的繁殖，用自我类似的方法。在自我类似的 solitons 形式的分析答案确切被获得。我们由直接数字的模拟证实这些答案的稳定性，并且发现稳定的空间 solitons 能在各种各样的形式存在，例如 Gaussian solitons，放射状地对称的 solitons，多极 solitons，和 soliton 旋涡。

Temporal Behavior of Low-Amplitude Grey Spatial Solitons in Biased Two-Photon Photorefractive Crystals

在低振幅的政体由于二光子的 photorefractive 效果屏蔽空间 solitons 的灰色的时间的性质被分析。结果显示宽广 solitons 在开始被产生，并且向稳定的状态 monotonically 作为时间发展灰 solitons 减少的紧张宽度到最小的价值。在一样的繁殖时间， solitons 的 FWHM 与增加或 m 减少减少。而且， solitons 的形成时间是独立人士和 m。时间接近到绝缘的松驰时间决定的一个常数。

Waveguides Induced by Screening-Photovoltaic Solitons in Biased Photorefractive-Photovoltaic Crystals

We investigate theoretically waveguides induced by screening-photovoltaic solitons in biased photorefractive-photovoltaic crystals. We show that the number of guided modes in a waveguide induced by a bright screening photovoltaic soliton increases monotonically with the increasing intensity ratio of the soliton, which is the ratio between the peak intensity of the soliton and the dark irradiance. On the other hand, waveguides induced by dark screening-photovoltaic solitons are always single mode for all intensity ratios and the confined energy near the centre of a dark screening-photovoltaic soliton increases monotonically with the increasing intensity ratio. When the bulk photovoltaic effect is neglectable, these waveguides are those induced by screening solitons. When the external field is absent, these waveguides predict those induced by photovoltaic solitons.

Rotating soliton clusters in nonlocal nonlinear media

From the study of the dynamics for the ring-like soliton clusters, we find that there exists a critical value of the ring radius, dcr, for the stationary rotation of the clusters with respect to the beam centre even in the presence of the relatively strong noise, and that the soliton clusters will not rotate but only undergo periodic collisions in the form of simple harmonic oscillator if the ring radius is large enough. We also show that the direction of the rotation can be opposite to the direction of phase gradient when the relative phase difference is within the domain 0 〈 ｜θ｜ 〈 π, while along the direction of phase gradient when the relative phase difference is within the domain π 〈｜θ｜ 〈 2π

Quasistable bright dissipative holographic solitons in photorefractive two-wave mixing system

The dynamical evolution of both signal and pump beams are traced by numerically solving the coupled-wave equation for a photorefractive two-wave mixing system. The direct simulations show that, when the intensity ratio of the pump beam to the signal beam is large enough, the pump beam presents a common decaying behaviour without modulational instability （MI）, while the signal beam can evolve into a quasistable spatial soliton within a regime in which the pump beam is depleted slightly. The larger the ratio is, the longer the regime is. Such quasistable solitons can overcome the initial perturbations and numerical noises in the course of propagation, perform several cycles of slow oscillation in intensity and width, and persist over tens of diffraction lengths. From physical viewpoints, these solitons actually exist as completely rigorous physical objects. If the ratio is quite small, the pump beam is apt to show MI, during which the signal beam experiences strong expansion and shrinking in width and a drastic oscillation in intensity, or completely breaks up. The simulations using actual experimental parameters demonstrate that the observation of an effectively stable soliton is quite possible in the proposed system.

Evolution and Stability of Dark Holographic Solitons in Photorefractive Dissipative Systems

如果，在一个消散的系统的黑暗 holographic 解决方案的动力学进化数字地被调查双平衡，即衍射被非线性平衡，损失被获得平衡，满足。系统参数的影响例如在输入横梁之间的水晶，外部偏导的域和天使的线性损失，数字地在 soliton 横梁的稳定的繁殖上被讨论。结果证明 suchsolitons 能被调整这些系统参数容易放大或吸收。而且，数字模拟显示消散的黑暗 holographic solitons 为振幅的小不安是稳定的。