共查询到19条相似文献,搜索用时 140 毫秒
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截断光束的二阶矩矩阵 总被引:1,自引:0,他引:1
采用复高斯展开法和维格纳分布函数(WDF),推导出了截断光束的二阶矩矩阵通过大气湍流的传输公式。研究表明,将硬边光阑的复高斯展开函数引入z=0平面处的WDF中,能够避免截断光束二阶矩的积分发散问题,得到z=0平面处二阶矩的解析结果,并且保证了精度,从而方便地得到截断光束在大气湍流中传输的二阶矩矩阵。实验所得到的结果具有一般性,即无截断光束的二阶矩矩阵通过大气湍流传输和截断光束的二阶矩矩阵在自由空间的传输都可以分别作为特例给出。 相似文献
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双曲余弦高斯光束通过有光阑限制的ABCD光学系统的传输 总被引:8,自引:0,他引:8
对双曲余弦高斯光束通过有硬边光阑的一阶ABCD光学系统的传输进行了研究,采用将矩形域函数表示为复高斯函数叠加的技巧,推导出了解析的传输公式,在特殊情况下,该公式简化为在无光阑情况下的传输公式,对双曲余弦高斯光束通过有光阑限制的薄膜镜聚焦进行了数值计算,计算结果与直接由柯林斯(Collins)公式所得结果一致,且此解析方法便于进行物理分析,可节约大量机时。 相似文献
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有振幅调制和相位畸变光束通过硬边光阑的M2因子 总被引:5,自引:3,他引:2
光束传输M^2因子是表征激光束的有用参量。利用矩形函数的复高斯函数的近似展开方法,给出部分相干光通过硬边光阑后强度二阶矩的近似计算公式,由此可得到部分相干光通过硬边光阑后的推广M^2因子。以有振幅调制和相位畸变光束为例,推导出相应的推广M^2因子的解析表达式,通过数值计算对提出的近似算法的计算精度进行了分析。研究结果表明,使用该近似方法计算得到的推广M^2因子的计算误差小于1%,且通过该方法可直接得到相应的近似解析计算公式,从而使计算得以简化,并有效地提高了计算效率。 相似文献
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Restoration of Decentered Gaussian Beam with the Combination of a Lens and a Gaussian Aperture 总被引:1,自引:0,他引:1
1 Introduction TheGaussianbeamisthefundamentalshapeofthelaserwithaspherical mirrorresonatorandwidelyusedtodescribeasinglemodelaser.Intheparaxialapproximation ,thedistributionofcomplexamplitudeofitremainsunchangedwhenitundergoestheFouriertransformorthe… 相似文献
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Yahya Baykal 《Optics & Laser Technology》2011,43(7):1237-1242
In weakly turbulent atmosphere, intensity correlations at the receiver plane are formulated for a general type optical beam. Evaluating our formula at the appropriate source parameters versus the diagonal distance, intensity correlations for cos Gaussian, cosh Gaussian, annular and flat-topped Gaussian beams are obtained. As compared to Gaussian beam, intensity correlations are found smaller for cos Gaussian and larger for cosh Gaussian beams. Intensity correlations of cos Gaussian, cosh Gaussian and flat-topped Gaussian beams become larger at large source sizes. Thicker annular beams and flatter flat-topped Gaussian beams show larger intensity correlations. Without generalizing, intensity correlations tend to increase when the link length and the structure constant decrease and the wavelength increases. Our results show that the intensity correlations are not only built up using random medium effects, but also using the diffraction pattern formed at the receiver plane for the specific incidence investigated. As a check point, for all source types and medium parameters, our evaluations indicate that intensity correlations approach zero at sufficiently large diagonal distances. 相似文献
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In this letter, the axial distribution of Gaussian beam limited by a hard-edged aperture is studied. We theoretically analyze the axial diffraction of Gaussian beam limited by a hard-edged aperture, and give the simpler formulas of the axial diffraction intensities of Gaussian beam in Fresnel diffraction field and Fraunhofer diffraction field. The corresponding numerical calculation of axial diffraction intensity distribution of Gaussian beam with different wave waist is provided and the evolution of the diffraction distribution with the wave waist of Gaussian beam is explained. As the especial cases of the truncated Gaussian beam,the Gaussian beam in free space and the parallel light limited by the aperture are discussed too, and the system parameters of the truncated Gaussian beam which can cause it to equal to these cases are given.The theoretical results conform to the numerical analysis. 相似文献
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The Gaussian spin model with periodic interactions on the diamond-type hierarchical lattices is constructed by generalizing that with uniform interactions on translationally invariant lattices according to a class of substitution sequences.The Gaussian distribution constants and imposed external magnetic fields are also periodic depending on the periodic characteristic of the interaction onds.The critical behaviors of this generalized Gaussian model in external magnetic fields are studied by the exact renormalization-group approach and spin rescaling method.The critical points and all the critical exponents are obtained.The critical behaviors are found to be determined by the Gaussian distribution constants and the fractal dimensions of the lattices.When all the Gaussian distribution constants are the same,the dependence of the critical exponents on the dimensions of the lattices is the same as that of the Gaussian model with uniform interactions on translationally invariant lattices. 相似文献
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In this paper, we consider the classical capacity problem for Gaussian measurement channels. We establish Gaussianity of the average state of the optimal ensemble in the general case and discuss the Hypothesis of Gaussian Maximizers concerning the structure of the ensemble. Then, we consider the case of one mode in detail, including the dual problem of accessible information of a Gaussian ensemble. Our findings are relevant to practical situations in quantum communications where the receiver is Gaussian (say, a general-dyne detection) and concatenation of the Gaussian channel and the receiver can be considered as one Gaussian measurement channel. Our efforts in this and preceding papers are then aimed at establishing full Gaussianity of the optimal ensemble (usually taken as an assumption) in such schemes. 相似文献
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研究了一维(1D)线阵离轴高斯光束通过湍流大气的传输特性,推导出了其光强传输方程. 研究表明,1D线阵离轴高斯光束通过湍流大气传输经历了三个阶段,即在近场其光强分布为类似于入射光的锯齿状分布,随着传输距离的增加逐渐变为平顶分布,最后在远场成为类高斯分布. 湍流的增强会使光束传输经历三阶段的进程加快. 并且,湍流使得不同子光束数的1D线阵离轴高斯光束的归一化光强分布相接近. 此外,子光束数越多的1D线阵离轴高斯光束受到湍流的影响越小;1D线阵离轴高斯光束较高斯光束受到湍流的影响要小.
关键词:
一维(1D)线阵离轴高斯光束
湍流大气
传输特性 相似文献