共查询到18条相似文献,搜索用时 125 毫秒
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在数值和实验上研究了向列相液晶中空间光孤子的相互作用.向列相液晶中的响应函数为指数衰减函数,这不同于Snyder-Mitchell模型.数值模拟发现向列相液晶中的孤子相互作用仍然满足交叉点位置与输入功率的平方根成反比,强非局域下的Snyder-Mitchell模型交叉点位置与两束光的间距无关,而在向列相液晶中交叉点位置与两束光的间距有关;在实验上发现,向列相液晶中两束光交叉点的位置与输入功率平方根成反比,还和形成孤子的临界功率以及两束光之间的间距有关. 相似文献
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研究了在强非局域情况下,非局域非线性介质中多个(大于两个)空间孤子相互作用的特点与规律。以Snyder-Mitchell线性模型为理论基础并利用线性叠加原理来构建解。另外,还采用了将孤子作为粒子处理的方法。主要考虑空间斜对称入射的三、四束光的相互作用,从而得出多个空间孤子相互作用的规律。还得出了(1 2)维多孤子相互作用的精确解析解,并且利用解析解画出了多孤子传输过程中的光强分布图。根据解析解发现,多孤子能形成稳定的束缚态向前传输,缠绕与否与初始入射方向有关;作用过程中并无能量转移,且相互作用与初始相位无关。将孤子作为粒子处理得到的孤子相互作用的规律与解析解得出的规律一致。 相似文献
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对非局域非线性介质中的空间暗孤子进行了研究.理论上运用牛顿迭代法求解非局域非线性薛定谔方程,得到了不同传播常数下的非局域空间暗孤子的数值解,发现在任何非局域程度以及任何传播常数条件下,都存在暗孤子的解,而且孤子的束宽与非局域程度存在一定的关系.实验上,在染料溶液中观测到了空间暗孤子在非局域非线性介质中的形成.利用输入功率所引起的非线性效应强度的变化,分析了背景光波形对暗孤子的影响,数值模拟结果与实验结果相符合.
关键词:
非局域非线性
空间暗孤子 相似文献
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针对热效应的非局域程度和分子取向效应的非局域程度不等的情况,利用JUNG P S等提出的模型研究了具有竞争非局域非线性效应的向列相液晶中的亮孤子特性.通过变分法得到光束振幅、宽度、啁啾和位相等参数随传输距离的变化规律,即光束振幅和宽度与入射光的功率息息相关,光束宽度随热非局域程度增加单调递减,随热非线性系数增加单调递增.在此基础上给出和入射光束功率密切相关的势能函数.利用势能函数预言了入射光束功率越大亮孤子宽度越小.通过解变分方程组可得,入射光功率为4或8时,光束宽度均随传输距离周期性震荡.这两个震荡趋势有明显的区别,功率为4时光束传输过程中宽度始终大于或等于初始宽度,功率为8时光束传输过程中宽度始终小于或等于初始宽度.该变化规律与数值仿真结论一致. 相似文献
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We address the physical features exhibited by spatial optical solitons propagating in nonlocal Kerr-type media with Gaussian-shaped response and exponential-decay response, respectively. An iteration algorithm based on the split-step Fourier method is developed to obtain the numerical solutions of the solitons for the nonlocal nonlinear Schrödinger equation with arbitrary degrees of nonlocality. Our numerical results show that the soliton properties in the normalized system are different with the change of the degree of nonlocality and with the different responses. The profiles undergo a gradual and continuous transition from a Gaussian-shaped function in the strongly nonlocal case to a hyperbolic secant function in the local case for the Gaussian-shaped response, but for the exponential-decay response, the soliton profile is not Gaussian-shaped even in the strongly nonlocal cases. For the same response function, the stronger the nonlocality is, the higher the critical powers for solitons are and the larger of the phase shifts of the solitons. For the same degrees of nonlocality, when the degrees of nonlocality is larger enough, both the critical power and the phase shift for the Gaussian-shaped response are larger than that for the exponential-decay response. 相似文献
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The solutions of the strongly nonlocal spatial solitons with several types of nonlocal response functions 总被引:3,自引:0,他引:3 下载免费PDF全文
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. 相似文献
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Propagation of optical solitons in lossy nonlocal media with exponential-decay response was investigated theoretically. The analytical solutions of nonlocal solitons and breathers are obtained by variational approach which is applied to a (1 + 1)D nonlocal nonlinear Schrödinger equation. The critical power of soliton and period of breathers are also obtained in the absence of the loss. When the loss is relatively small, the average beam width of breathers has a trend to expand during propagation. The analytical results are confirmed by numerical simulation. 相似文献
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Self-bending of photorefractive solitons 总被引:7,自引:0,他引:7
Self-bending of photorefractive solitons is caused by diffusion in photorefractive crystals and becomes an important effect when the beam size is in the range of the charge carriers diffusion length. In this paper we present an experimental and numerical examination of the beam bending dependence on relevant parameters such as the applied electric field and the beam intensity. We demonstrate that the bending dependence on the electric field in the low saturation regime has the form of a square function at low values of the field and becomes linear for higher values. For stronger saturation the curve gets the form of a square root function. The bending dependence on the beam intensity has a maximum at defined intensity. The experimental data are compared with numerical simulations, giving a good qualitative agreement. 相似文献
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Mário F. S. Ferreira 《Fiber and Integrated Optics》2013,32(3):113-126
Abstract The polarization-mode dispersion (PMD) is a dominant statistical effect in ultra-high bit rate transmission systems. In this article, soliton transmission in constant and randomly varying birefringent fibers is reviewed. In particular, soliton robustness to PMD is analyzed and compared with that of linear pulses. It is found that solitons broaden in proportion to the square root of distance, like in the case of linear pulses, but with a reduced coefficient. 相似文献
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We theoretically investigate the propagation of incoherently coupled Hermite-Gaussian breather and soliton pairs in strongly nonlocal nonlinear media. It is found that multipole-mode soliton pairs with arbitrary different orders of Hermite-Gaussian shape can exist when the total power of two beams equals the critical power and the ratio of the beam widths for the Gaussian part is inversely proportional to the square root of the ratio of the wave numbers. When the total power does not equal the critical power, the Hermite-Gaussian breather pair exists and their beam widths evolve analogously. For general cases where the ratio of the beam widths is arbitrary, soliton-breather pairs or breather-breather pairs can be formed and their beam widths evolve synchronously in-phase or out-of-phase. Numerical simulations directly based on the nonlocal nonlinear Schrödinger equation are conducted for comparison with our theoretical predictions. The numerical stability analysis shows the higher-order Hermite-Gaussian solitons can not be stable for small nonlocality or for some media like liquid crystals. 相似文献
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在非局域非线性克尔介质中,通过对介质实对称响应函数的泰勒展开,简化了非局域非线性薛定谔方程所对应的Lagrange密度,进而利用变分法对光束的传输问题进行了分析.求出试探解各个参量的演化方程并得到了自聚焦介质中的厄米高斯型光束的精确解析解,当输入功率达到临界功率时,即形成高阶空间光孤子(厄米高斯孤子),其最低阶(基模光孤子)就是高斯孤子.通过数值模拟发现解析解与数值解符合得很好.
关键词:
非局域克尔介质
变分法
厄米高斯光束
空间光孤子 相似文献