共查询到18条相似文献,搜索用时 156 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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光束在非局域非线性介质中传输由非局域非线性薛定谔方程描述.讨论了在不同非局域程度 条件下,空间光孤子的传输特性.提出了一个基于分步傅里叶算法数值求解孤子波形和分布 的迭代算法.假定介质的非线性响应函数为高斯型,得出了在不同非局域程度条件下空间光 孤子的数值解,并数值证明了它们的稳定性.结果表明,不论非局域程度如何,光束都能以 光孤子态在介质中稳定传输.光孤子的波形是从强非局域时的高斯型过渡到局域时的双曲正 割型,形成孤子的临界功率随非局域程度的减弱而减小,光孤子相位随距离线性增大,相位 的变化率随非局域程度的减弱而减小.
关键词:
非局域非线性薛定谔方程
空间光孤子
临界功率
相位 相似文献
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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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《中国光学与应用光学文摘》2007,(3)
非线性光学概论O4372007032364向列相液晶中强非局域空间光孤子的实验观察=Experi-mental observation of strong nonlocal optical spatial soli-tons in nematic liquid crystals[刊,中]/张涛(华南师范大学信息光电子科技学院传输光学实验室,广东省高校光子信息技术重点实验室.广东,广州(510006)),胡巍…//光学学报.?2007,27(1).?143-147通过实验对向列相液晶中的非局域空间光孤子的传输进行了研究。理论上基于非线性的液晶孤子传输方程,采用高斯形式的试探解,得到了孤子传输的解析解,以及对液晶中的非局域孤子和Snyder等提出的强非局域… 相似文献
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从(1+2)维非局域非线性薛定谔方程出发, 通过坐标变换得到了旋转坐标系下的非局域非线性薛定谔方程. 假设响应函数为高斯型, 用虚时间法数值求解了旋转坐标系下的非局域非线性薛定谔方程的静态孤子解, 迭代出了不同非局域程度条件下的静态椭圆孤子数值解. 最后采用分步傅里叶算法, 以迭代的孤子解作为初始输入波形, 模拟了在不同的非局域程度条件下, (1+2)维椭圆空间光孤子的旋转传输特性. 强非局域时, 椭圆光孤子的长轴方向和短轴方向波形都是高斯型, 其他的非局域程度下, 不是高斯型. 由此表明:(1+2)维椭圆光孤子对非局域程度依赖性很强. 旋转角速度和功率均与非局域程度以及孤子的椭圆度有关. 相似文献
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基于强非局域非线性介质中的Snyder-Mitchell模型,利用分离变量法得到了(1 1)维光束传输的厄米-高斯型解析解.比较厄米-高斯型解析解与非局域非线性薛定谔方程的数值解,证实了,在强非局域条件下,该厄米-高斯型解与数值解完全吻合.对厄米-高斯光束的传输特性进行研究,结果表明,光束束宽会出现周期性的压缩或者展宽现象.并且得到了实现厄米-高斯光束稳定传输的临界功率、厄米-高斯孤子解及传输常量,临界功率与厄米-高斯光束的阶数无关,但传输常量随阶数的增加而增加.高斯呼吸子和高斯孤子就是基模厄米-高斯呼吸子和基模厄米-高斯孤子. 相似文献
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The propagation of four-petal Gaussian beams in strongly nonlocal nonlinear media has been studied. The analytical solution and the analytical second-order moment beam width are obtained. For the off-waist incident and the waist incident cases, the intensity pattern evolves periodically during propagation in strongly nonlocal nonlinear media. Under the off-waist incident condition, the second-order moment beam width varies periodically during propagation, whatever the input power is. But under the waist incident condition, there exists a critical power. When the input power equals the critical power, the second-order moment beam width remains invariant, otherwise the second-order moment beam width varies periodically. Numerical simulations based on the nonlocal nonlinear Schrödinger equation are carried out for comparison with the theoretical predictions. The results show that the numerical simulations are in good agreement with the analytical results in the case of strong nonlocality. 相似文献
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The interaction trajectory of solitons in nonlocal nonlinear media is investigated. A simple differential equation describing the interaction trajectories is derived based on the light ray equation. Numerical calculations are carried out to illustrate the interaction trajectories with different parameters. The results show that the degree of nonlocality greatly affects the interaction of solitons. For a strongly nonlocal case, the interaction trajectory can be described by a cosine function. Analytical expressions describing the trajectory and the oscillation period are obtained. For generally and weakly nonlocal cases, the interaction trajectories still oscillate periodically, however it is no longer sinusoidal and the oscillation period increases with the nonlocal degree decreasing. In addition, the trajectory of two solitons launched with a relative angle at the entrance plane is investigated. It is found that there exists a critical angle. When the initial relative angle is larger than the critical angle, the two solitons do not collide on propagation. The influence of the degree of nonlocality on the critical angle is also discussed. 相似文献
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We present a study of the effect of weak anchoring on the transition between C1 and C2 chevron structures in smectic-C liquid
crystals. The coexistence of C1 and C2 chevron structures within a single cell causes zigzag defects to occur and may affect
the optical characteristics of the cell. By standard Euler-Lagrange minimisation of the total energy of the system, we obtain
analytical expressions for the equilibrium director cone angle in the two chevron states. These in turn allow us to compare
the total energies of the states and determine the globally stable chevron profile. We show that analytical predictions for
the critical transition temperature, which depends on anchoring strength and pretilt angle, are in good agreement with those
obtained numerically. 相似文献
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We study the propagation of (1+1)-dimensional spatial soliton in a
nonlocal Kerr-type medium with weak nonlocality. First, we show that
an equation for describing the soliton propagation in weak
nonlocality is a nonlinear Schr?dinger 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. 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