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.
关键词:
强非局域非线性
向列相液晶
孤子相互作用
交叉点 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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《量子光学学报》2021,(3)
空间光孤子是介质衍射效应和非线性效应相平衡的结果。当两束非相干光在非线性介质中传输时,两孤子发生交叠而产生相互作用,本文研究自散焦介质中非相干耦合暗孤子对的传输特性和相互作用。基于描述光束传播的耦合非线性薛定谔方程组,利用变分法,首先得到了自散焦克尔介质中传输的两暗孤子的幅值、横向中心位置坐标、速度和相位随传输距离变化的参数演化方程组,讨论了孤子参数演化的规律。然后,为分析孤子间相互作用,导出了两幅值相等的暗孤子在传输过程中孤子间距随传输距离的变化规律,作出了孤子对传输图像和相互作用图像,最后导出了孤子间相互作用势能和相互作用力的表达式,并利用图像详细分析了孤子间的相互作用特性。研究结果表明:无损耗情况下,孤子的幅值不受耦合作用的影响,传输过程中保持不变;耦合相互作用使两孤子横向中心位置坐标发生明显漂移,当两孤子间距较小时,孤子间距随传输距离作变速变化,变化速率与孤子的幅值和耦合程度有关,当两孤子间距趋近于零时,孤子间距随传输距离呈匀速的稳定变化;暗孤子间的相互作用力为排斥力,随着孤子间距增大,排斥力先增大后减小,而相互作用势能一直逐渐减小,当孤子间距增至4.5附近时,孤子间势能减小到几乎为零。 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 Schr\"{o}dinger 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 $m$th 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