共查询到19条相似文献,搜索用时 62 毫秒
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负折射率媒质是一种人造媒质,在某一微波波段内其介电常数和磁导率同时为负值。对TE模电磁场满足的麦克斯韦方程组进行数值处理,解决了直接利用时域有限差分方法在Yee’s网格下计算负折射率媒质内部场分布时的数值发散问题。通过数值算例,验证了方法的可行性,模拟了负折射率媒质内部及周围的电磁场分布。 相似文献
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根据色散媒质的性质及电磁波在不同媒质交界面上的反射的机理,证明并分析了在理想匹配层吸收边界中引入色散可实现有效吸收入射到吸收边界上的电磁波,从而达到减少时域有限差分法计算区域和计算误差的目的。 相似文献
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文章提出一种横向激发的任意线偏振高斯光束,该光束场量的模与传统的任意线偏振高斯光束具有相同的模,在源场区,其满足自由空间无源场的场方程。同时利用瑞利—索末菲衍射积分对该高斯光束的非傍轴传输特性进行了解析研究,给出了空间光强分布、束腰和远场发散角的解析通式,发现该类光束的远场光强呈一平顶空心光束。 相似文献
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This study presents the electromagnetic wave propagation through the frequency-dispersive and lossy double-negative slab embedded
between two different semi-infinite media. The double-negative slab is realized by using two models, the Lorentz and Drude
medium models. The properties and the required equations for the frequency-dispersive and lossy double-negative slab, the
Lorentz medium and Drude medium are given in detail. After the construction of the problem, the reflection and transmission
coefficients are derived for both TE and TM waves. Then, the reflected, transmitted and loss powers are determined using these
coefficients. Finally, in the numerical results, the mentioned powers for TE and TM waves are computed and illustrated as
a function of the incidence angle, the frequency and the slab thickness when the damping frequency changes. 相似文献
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The propagation characteristics of TM polarized Gaussian beam, which is the rigorous solution of an eigenfunction problem for a confocal resonator, have been investigated using the nonparaxial vectorial moment theory of light beam propagation. The analytical expressions of the beam propagation factors are given by means of Fourier transform. Both the transversal second-order moment beam widths follow a simple hyperbolic variational law. For nonparaxial case, however, beam has different propagating features in the two transversal directions. As to paraxial case, its propagation approximately reduces to that of scalar Gaussian beam TEM00 mode. 相似文献
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By expanding the hard aperture function into a finite sum of complex Gaussian functions, some approximate analytical formulae for the cross-spectral density of a partially coherent flattened Gaussian beam (FGB) propagating through apertured aligned and misaligned ABCD optical systems are derived based on the generalized Collins formula. The results obtained by using the approximate analytical formula are in good agreement with those obtained by using the numerical integral calculation. As a numerical example, the focusing properties (including average irradiance distribution and focal shift) of a partially coherent FGB focused by an apertured thin lens are studied, and it is found that the focusing properties of a partially coherent FGB are closely related to its initial coherence and the aperture width. Our results provide an effective and fast way for studying the paraxial propagation of a partially coherent FGB through apertured ABCD optical systems. 相似文献
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高斯光束通过非线性介质层的限幅效应 总被引:2,自引:0,他引:2
本文用数值分析的方法研究了两维高斯光束通过一定厚度的非线性折射介质后在线性空间传播的状态,分析了光束的近场和远场横向强度分布及通过一定孔径光阑的功率.结果表明,在考虑到光束经过非线性介质时,相位与横向分布都会发生变化后,仅在非线性折射效应作用下,在远场就存在限幅效应.在一定的强度范围之内,近场也存在限幅利用的可能性. 相似文献
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扩束准直光学系统中光学元件失调对高斯光束传输变换的影响分析 总被引:1,自引:1,他引:1
基于广义惠更斯-菲涅尔衍射积分公式, 以高斯光束为激光束模型,推导了激光光束通过失调扩束准直光学系统的传输公式,分析了光学元件失调对扩束准直光学系统输出光束传输特性的影响,并在此基础上进行了仿真。实验结果表明,高斯光束通过失调扩束准直光学系统时,出射光束变为偏心高斯光束,光学元件失调程度越大,输出光束越偏离光轴,光束质量越差。在同样的失调下,长焦距光学元件对输出光束影响更大,因此在激光扩束准直光学系统中,调整长焦距光学元件更为重要。 相似文献
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Propagation dynamics of a two-dimensional Airy Gaussian beam and Airy Gaussian vortex beam are investigated numerically in local and nonlocal nonlinear media. The self-healing and collapse of the beam crucially depend on the distribution factor b and the topological charge m. With the aid of nonlocality, a stable Airy Gaussian beam and an Airy Gaussian vortex beam with larger amplitude can be obtained, which always collapse in local nonlinear media. When the distribution factor b is large enough, the Airy Gaussian vortex beam will transfer into quasi-vortex solitons in nonlocal nonlinear media. 相似文献