共查询到16条相似文献,搜索用时 359 毫秒
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利用Wigner分布函数(WDF)方法,对光束的分数傅里叶变换特性进行了研究.以厄米 高斯(H G)光束为例,导出了H G光束在分数傅里叶变换面上光强分布的解析公式和H G光束在分数傅里叶变换面上束宽的解析计算公式.通过数值计算研究了H G光束光强随分数傅里叶变换阶数变化的规律.研究表明:选取适当的分数傅里叶变换阶数p,在x,y方向可以得到相等束宽的对称光强分布.
关键词:
Wigner分布函数
厄米 高斯(H G)光束
分数傅里叶变换 相似文献
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引入了一簇互相正交的超洛伦兹-高斯光束以描述半导体激光器所产生的大角度高阶模远场分布。将分数傅里叶变换应用于超洛伦兹-高斯光束SLG11模的传输特性的研究中。利用傅里叶变换的卷积原理,导出了SLG11模经分数傅里叶变换系统后场分布的解析表达式。根据所得到的公式进行了数值计算,系统分析了分数傅里叶变换阶数和光束各参数对SLG11模在分数傅里叶变换面上光强分布的影响。结果显示:SLG11模在分数傅里叶变换面上的归一化强度分布随分数傅里叶变换的阶数呈周期性变化,周期为2;随着光束参数的增大,SLG11模在分数傅里叶变换面上的光斑尺寸增大。 相似文献
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《光学学报》2017,(2)
实际应用中球差作为一种普遍存在的像差,对光束在光学系统中的传输具有较大影响。为了研究球差对光束通过分数傅里叶变换系统后所产生的影响,基于柯林斯公式,推导出余弦高斯光束在有球差和无球差的分数傅里叶变换系统中的场分布,并以LohmannⅠ型系统为例,进行数值模拟计算,研究了余弦高斯光束通过有球差和无球差的分数傅里叶变换系统后输出面的横向光强分布规律以及不同变换阶数和不同调制参数下轴上光强大小与球差系数的关系。结果表明,在分数傅里叶变换系统中,透镜球差对输出面横向光强分布有较大影响,并且正球差和负球差对横向光强的影响效果有明显区别。不同变换阶数和不同调制参数下透镜球差对轴上光强的作用效果不同。 相似文献
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为研究非相干的1维线阵离轴高斯光束通过分数傅里叶变换(FRFT)系统的传输特性,利用Collins积分公式,导出了其在FRFT面上的光强分布解析式,并利用此解析式作数值计算和分析。研究表明:非相干的1维线阵离轴高斯光束在FRFT面上的光强分布由FRFT的阶数和子光束数目共同决定,其归一化的光强分布随FRFT的阶数周期性变化,周期为2;子光束数目的大小及其奇偶性对归一化光强分布的影响取决于FRFT的阶数;轴上归一化光强分布也随FRFT的阶数周期性变化,变化周期也为2。 相似文献
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从描述强非局域介质中光束传输的非线性薛定谔方程出发,研究了(2+1)维双曲余弦高斯光束在强非局域介质中的传输性质及其相互作用,给出了双曲余弦高斯光束在强非局域非线性介质中传输的解析表达式和二阶矩束宽的解析表达式,同时对两束双曲余弦高斯光束之间的相互作用进行了解析和数值分析。结果表明单光束入射强非局域介质时,存在一个临界功率,当入射功率等于临界功率时,光束在传输过程中的二阶矩束宽可以保持不变;当入射功率不等于临界功率时,光束的二阶矩束宽呈周期性变化。两束双曲余弦高斯光束共同传输时会相互吸引,并且横向强度分布变的较为复杂,给出了两束光传输时相互作用后的强度分布和轴上光强演化等结果。 相似文献
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An analytical expression of an Airy beam passing through a fractional Fourier transform (FRFT) system is presented. The effective beam size of the Airy beam in the FRFT plane is also derived. The influences of the order of FRFT, the modulation parameter, and the transverse scale on the normalized intensity distribution and the effective beam size of an Airy beam in the FRFT plane are examined. The order of FRFT controls the effective beam size and the orientation of the beam spot. The modulation parameter affects the effective beam size and the number of lateral side lobes. The normalized intensity distribution and the effective beam size are both proportional to the transverse scale. 相似文献
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This paper introduces Lorentz beams to describe certain laser
sources that produce highly divergent fields. The fractional Fourier
transform (FRFT) is applied to treat the propagation of Lorentz
beams. Based on the definition of convolution and the convolution
theorem of the Fourier transform, an analytical expression for a
Lorentz beam passing through a FRFT system has been derived. By
using the derived formula, the properties of a Lorentz beam in the
FRFT plane are illustrated numerically. 相似文献
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Based on the generalized Huygens–Fresnel integral, the analytical expressions for Airy beams through three types of fractional Fourier transform (FRFT) optical systems (Lohmann I, Lohmann II and quadratic graded-index systems) are derived. Using the two analytical expressions, the propagation properties of Airy beams for the three types of FRFT optical systems are discussed in detail with numerical examples. Results indicate that the intensity of Airy beams periodically changes and remains form-invariant with the changing of fractional order p for the three types of FRFT optical systems. 相似文献
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Cosh-Gaussian beams are of practical interest because they are more efficient at extracting energy from conventional laser amplifiers, and they have some important applications because their profiles can closely resemble the flat-top field distribution by choosing suitable beam parameters of cosh parts. The fractional Fourier transform (FRFT) is applied to treat the propagation of off-axial elliptical cosh-Gaussian beams (EChGBs). By the use of vector integration, the analytical expression for an off-axial EChGB passing through a FRFT system is derived in terms of tensor method. Our formula provides a convenient way for studying the FRFT of off-axial EChGBs; some numerical simulations are also given. 相似文献
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A new kind of laser beams named the elliptical Hermite-sinusoidal-Gaussian beams (EHSGBs) is introduced and defined by use of tensor method, and the elliptical Hermite-cosh-Gaussian beam (EHChGB) can be regarded as special case of EHSGBs. The fractional Fourier transform (FRFT) is applied to treat the propagation of EHChGBs. An analytical expression for an EHChGB passing through an FRFT system is derived by using vector integration. Some numerical simulations are illustrated for the propagation properties of EHChGBs through FRFT systems. 相似文献
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Based on Collins integral formula and the fact that a hard aperture function can be expanded into a finite sum of complex Gaussian functions, the propagation properties of cosh-squared-Gaussian beam passing through ideal and apertured FRFT systems have been studied, and some comparisons between using the methods of analytical formula and diffraction integral formula have been done. Further, the studies indicate that the normalized intensity distributions on FRFT plane depend on the fractional order, truncation parameter and initial beam parameter Ω. Variations of normalized intensity distributions with FRFT order are periodic: when the impact of aperture cannot be ignored, the variation period is 4; and when the impact of aperture can be ignored, the variation period is 2. 相似文献