共查询到20条相似文献,搜索用时 62 毫秒
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利用强非局域非线性介质中傍轴光束传输的修正Snyder-Mitchell模型讨论了两束共线(即光束中心和传输方向都相同)拉盖尔-高斯型光孤子(CLGS)构成的涡旋光孤子传输过程。在一定条件下,涡旋光束在传输过程中,光束截面光斑发生旋转现象,但光束的束宽保持不变,称之为旋转涡旋光孤子。涡旋光孤子旋转的现象可以通过叠加光场中的古依相位来解释。结果展现了几个旋转涡旋光孤子在传输过程中的旋转现象和强非局域介质中多环形旋转涡旋光孤子的传输。 相似文献
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利用强非局域非线性介质中傍轴光束传输的线性模型(修正的Snyder-Mitchell模型)讨论了两束共线(即光束中心和传输方向都相同)拉盖尔-高斯型光孤子的传输过程. 改变双光束的相对阶数和相对强度比,叠加光场在传输截面上的光强分布呈现出多样性,通过叠加的方法在该介质中产生了多环形光孤子. 一定条件下传输光束在传输过程中会出现旋转现象,叠加光场成为旋转光场,给出了旋转光束的旋转条件以及旋转速度. 进一步利用拉盖尔-高斯光束在传输过程中特有的螺旋相位特点分析了光场截面强度多样性产生的物理机理.
关键词:
强非局域非线性介质
拉盖尔-高斯型光孤子
共线传输
涡旋相位 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
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以线性传输模型为对比研究了不同初始能量的环形光束在空气中的非线性传输。结果显示,在传输初始阶段,非线性克尔效应减弱了线性空间啁啾导致的聚焦作用。线性聚焦使能量向光轴方向流动导致强光强核心,在光轴附近生成类高斯脉冲结构,增强了非线性自聚焦效应,导致光强急剧增加形成光丝。环形光束的初始能量的大小能够影响自聚焦焦距、光丝长度和光强通量。自聚焦焦距随着初始脉冲能量的增加而减小,但自聚焦焦距与初始功率的开方不成反比(这点与高斯光束不同)。光丝长度随着初始脉冲能量的增加而增加。轴上光强通量随初始脉冲能量的增加而增加。 相似文献
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研究了有限能量Airy光束在克尔介质中的非线性传输过程及整体自聚焦(特别是小尺度自聚焦)特性.研究发现相对于整体自聚焦,有限能量Airy光束主峰的小尺度自聚焦更容易发生,而且其噪音调制的增长速度随着截断系数的增加而变慢.通过对比研究不同截断系数小尺度自聚焦的增益谱,发现截断系数也极大地影响有限能量Airy光束的增益谱,截断系数越小Airy光束受噪音影响分裂的可能性就越大;对于较大的截断系数,有限能量Airy光束增益谱和由它主瓣拟合的高斯光束的增益谱越来越接近.研究结果对于有限能量Airy光束的潜在应用有一定的指导作用. 相似文献
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Zdeněk Bouchal 《Czechoslovak Journal of Physics》2003,53(7):537-578
The controversial term nondiffracting beam was introduced into optics by Durnin in 1987. Discussions related to that term revived interest in problems of the light diffraction and resulted in an appearance of the new research direction of the classical optics, dealing with the localized transfer of electromagnetic energy. In this paper, the physical concept of the nondiffracting propagation is presented and the basic properties of the nondiffracting beams are reviewed. Attention is also focused to the experimental realization and to applications of the nondiffracting beams. 相似文献
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To monitor the beam profile at the end of the linac non-destructively, a wire scanner as a new diagnostic instrument was designed, manufactured and installed in 2007. Since then, several measurements have been carried out using this device. This paper describes the whole system of the wire scanner and the testing results. 相似文献
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Generation of diffraction-free vectorial elliptic hollow beams with space-varying inhomogeneous polarizations 下载免费PDF全文
Hui-Rong Li 《中国物理 B》2021,30(8):84204-084204
Diffraction-free vectorial elliptic hollow beams (vEHBs) are generated by an optical system composed of a short elliptic hollow fiber (EHF) and an axicon. Each beam has a closed elliptic annular intensity profile and space-varying polarization states in its diffraction-free distance of more than 1 m. The generated beams have a counter-clockwise or clockwise periodically-rotated inhomogeneous polarization. And the spin angular momentum (SAM) of the vEHBs is 1ħ or -1ħ which is consistent with the type of dual-mode in the EHF and the periodic polarization rotations of the vEHBs. The vEHBs have potential applications in optically trapping and micromanipulating the micro- or nano-particles, quantum information transmission, and Bose-Einstein condensates, etc. 相似文献
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Ultra-thin two-dimensional transmissive anisotropic metasurfaces for polarization filter and beam steering application 下载免费PDF全文
We propose an anisotropic planar transmitting metasurface, which has the ability to manipulate orthogonally-polarized electromagnetic waves in the reflection and refraction modes respectively. The metasurface is composed of four layered rectangular patches spaced by three layered dielectric isolators each with a thickness of 0.15λ0 at 15 GHz. By tailoring the sizes of the patches, the metasurface functions as a band-stop filter for the y-polarzied wave and a band-pass filter for the x-polarized wave operating from 14 GHz to 16 GHz. Moreover the phases of the transmitting x-polarized wave can be modulated at about 15 GHz, which contributes to beam steering according to the general refraction law. Experimental results are in good accordance with the simulated ones, in which the reflection efficiency is almost 100% while the transmission efficiency of the x-polarized wave reaches 80% at 15 GHz. Besides, the transmitted x-polarized wave is effectively manipulated from 14 GHz to 16 GHz. 相似文献
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分析了在储存环中回旋的离子束与残余气体分子、 内靶和冷却电子束相互作用时的损失机制及相应的束流寿命, 针对兰州重离子加速器冷却储存环实验环内靶模式, 计算了50—500 MeV/u 12C6+, 36Ar18+, 132Xe54+和 238U92+等束流在各种损失机制影响下所对应的束流寿命和总的束流寿命。 结果表明: 影响束流寿命的主要因素是与内靶分子(原子)之间的电荷交换及与冷却电子束之间的辐射复合; 对于重离子束 132Xe54+和 238U92+, 与冷却电子束之间的辐射复合是影响其储存寿命的主要因素。The loss mechanism and lifetime of ion beams in collisions with residual gas, internal target and electrons in e cooler in heavy ion cooler storage rings were studied. The partial beam lifetimes resulting from various loss mechanisms and the total beam lifetimes of 50—500 MeV/u12C6+, 36Ar18+, 132Xe54+ and 238U92+ stored in the experimental ring of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL CSR) were calculated. The calculations indicate that the charge exchange process between ion beams and the internal target, as well as the radiative recombination process with the electrons in e cooler restrict the beam lifetime considerably. For heavy ion beams such as 132Xe54+ and 238U92+, the radiative recombination is the dominant loss mechanism 相似文献
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基于汉克尔波理论和衍射积分理论详细分析了轴棱锥对无衍射光束的线聚焦特性, 提出了一种产生周期性局域空心光束的新方法, 即无衍射贝塞尔光束经过轴棱锥聚焦后产生具有塔尔博特效应的局域空心光束. 数值模拟了无衍射贝塞尔光束照射轴棱锥后, 沿传输距离变化的光强分布及一个周期内光强的演变和局域空心光束的形成过程. 设计实验系统, 由He-Ne激光经过一套光学系统后透过轴棱锥, 产生近似无衍射贝塞尔光束, 再由第二个轴棱锥对产生的无衍射贝塞尔光束进行线聚焦, 在第二个轴棱锥后面由显微镜观测到周期性局域空心光束, 并用CCD照相机拍摄了两个周期内的光斑图, 实验结果和理论分析相符合. 研究结果可用于多层面微粒的操控, 对周期性局域空心光束在光学微操控领域的应用具有重要的指导意义.
关键词:
贝塞尔光束
轴棱锥
线聚焦
局域空心光束 相似文献
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从二阶矩的定义出发,给出了一类新光束———厄光双曲正弦高斯(HShG)光束M2因子的解析公式,公式表明HShG光束的M2因子是光束阶数n和参数α的函数.作为本公式的特例,给出了厄光正弦高斯(HSiG)双束、双曲正弦高斯(ShG)光束以及正弦高斯(SiG)光束M2因子的解析公式.对HShG光束的束腰宽度、远场发散角及M2因子做了数值计算,并对所得结果作了分析.
关键词:
厄米-双曲正弦高斯光束
厄米-正弦-高斯(HSiG)光束
M2因子
二阶矩 相似文献