共查询到20条相似文献,搜索用时 9 毫秒
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利用矢量衍射理论,研究了高数值孔径下高斯光束的超分辨特性,对可以实现超分辨的二环和三环相位结构进行了优化求解,分析了环带半径和相位变化对超分辨性能的影响规律,给出了优化方法和优化结果.研究结果表明:当和平面波照明具有相同的旁瓣比时,使用高斯光束照明仍然可以实现光学超分辨;采用二环相位结构时,内环半径的控制比较关键,相位的微小改变对超分辨性能的影响不大,二环相位结构具有加工容差大的优点;三环相位结构在相同旁瓣比的情况下能够达到较大的压缩比和较小的主瓣峰值强度,三环结构的半径和相位的改变对超分辨性能的影响较大,其加工容差要小于二环相位结构;无论二环或三环相位结构,若提高压缩比,必然会引起主瓣峰值强度降低和旁瓣比增大.该研究为高数值孔径下,高斯光束照明时,超分辨光瞳滤波器的优化设计提供了一种新方法. 相似文献
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A decentered flattened Gaussian beam (DEFGB), is defined by a tensor method. The propagation formula for a DEFGB passing through an axially nonsymmetrical paraxial optical system is derived through vector integration. The derived formula can be reduced to the formula for a generalized decentered elliptical flattened Gaussian beam under certain condition. As an example application of the derived formula, the propagation characteristics of a DEFGB in free space are calculated and discussed. As another example we have studied the properties of superposition with radial array consisted by DEFGB. 相似文献
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The propagation properties of decentered twisted Gaussian Schell-model (DTGSM) beams passing through a misaligned first-order optical system are studied. The explicit expressions for the cross-spectral density function and Wigner distribution function of the output beam are derived, which retain their form unchanged. It is shown that the DTGSM beams preserve their closed property. The second-order moments matrix and the Wigner distribution function evolve with the usual laws, whereas the first-order moments matrix varies, as if a ray passes through such system. The propagation of DTGSM beams through an aligned first-order optical system is treated as the limiting case that corresponds to the vanishing misalignment parameters. 相似文献
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孔径光阑限制下高斯光束的传输 总被引:8,自引:3,他引:5
对高斯光束在硬边孔径限制下的衍射进行了详细的理论研究,就不同口径的圆孔限制下高斯光束在菲涅耳衍射区和夫琅禾费衍射区的分布进行了理论分析,从而得到了孔径受限高斯光束的横向以及轴向的衍射公式,进而对高斯光束在不同衍射区域内衍射光场分布形状随孔径尺寸变化时的演化规律进行了数值计算,并对小口径光阑受限的高斯光束的衍射与平行光经同尺寸光阑的衍射进行了比较。结果表明在较小口径下,两者的分布基本一致。得到的孔径光阑限制下高斯光束的传输规律为高斯光束在自由空间光通信和光学超分辨中的应用提供了理论基础。 相似文献
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依据夫琅和费衍射理论,通过引入高斯变换,即把夫琅和费衍射积分中的贝赛尔函数用一高斯函数来近似,详细分析并推导出圆孔限制下具有相位变化的高斯光束远场发散度的近似计算公式.与传统数值积分求光束发散度相比,它避免了繁琐数值积分,其误差不超过3%. 相似文献
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The scattering and focusing characteristics of a Gaussian beam with phase distribution is studied by a stepped index Luneberg lens. A model experiment was performed using a six-layer spherical lens. Two kinds of beams, that is, broad and narrow beam are examined for the incident Gaussian beam. We find that focusing effect of a narrow beam is wholly lower than that of a broad beam. The focal point is also shifted toward outer of sphere because of phase lag for the beam source. The spot size equals almost the wavelength for the various beam parameters. 相似文献
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圆孔受限波差高斯光束的远场近似及发散度分析 总被引:4,自引:0,他引:4
引入复高斯函数对衍射受限的圆孔进行了复高斯分解,得到了波差高斯光束远场衍射的近似解析式。在各种参量条件下,近似解析式所表示的衍射图样与严格的夫琅和费衍射积分的衍射图样完全一致,这表明用此解析式表征远场衍射是正确的。它的形式相对简单,为计算带来极大的方便。基于此,对有波差的高斯光束的远场发散度进行了深入的研究,检验了确定参量的光束随距离的改变而发散度不被改变的特性;同时,探讨了在圆孔限制下,发散度随高斯光束的束腰及波差的改变而变化的关系曲线,结果表明,这两个参量是影响发散度的主要因素。 相似文献
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为分析平顶高斯光束通过光学系统传输时圆孔光阑失调和光学元件失调对平顶高斯光束传输特性的影响,利用失调圆孔光阑的近似展开式和适用于失调光学系统的广义衍射公式,得出了平顶高斯光束经含失调圆孔光阑的失调光学系统传输的近似解析式,给出了输出光束场分布与光束参量、光阑孔径尺寸、光阑和光学元件失调量等的定量关系.针对特定光学系统定量分析了各失调量对输出光束场分布的影响,结果表明各元件失调都对输出光束强度分布产生较大影响.但在各失调量较小的情况下,透镜失调对输出光束传输特性的影响比光阑失调对输出光束传输特性的影响更明显. 相似文献
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根据广义惠更斯-菲涅尔原理和Collins公式,基于复高斯函数展开法,推导出椭圆偏振的高斯-谢尔模型光束经过矩形光阑衍射后的交叉谱密度公式,结合斯托克斯矢量理论推导了椭圆偏振高斯-谢尔模型光束在接收平面的光强、偏振度、方位角和椭圆度的表达式,数值分析了光阑的孔径遮拦比对光强、偏振度及方位角和椭圆度的影响.结果表明,光阑的孔径遮拦比在近场区对经过光阑后椭圆偏振高斯-谢尔模型光束的光强和偏振特性有显著影响;随着传输距离的增大,光强和偏振特性受孔径遮拦比的影响减小,光强和偏振特性变化平稳. 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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1 Introduction Laserbeamswithamplitudemodulations(AMs)andphasefluctuations (PFs) proposedbytheLawrence LivermoreNationalLaboratory (LLNL)isatypicalphysicalmodelforhigh powerlasers[1] .Inhigh powerlasersystems,suchaslargeNd∶glasslaserfusiondrivers,high powerla… 相似文献
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Based on the treatment that a rectangular function can be expanded into an approximate sum of complex Gaussian functions with finite numbers, the analytical expression for the focusing intensity distribution of a laser beam with amplitude modulation (AM) and phase fluctuation (PF) through an aperture lens is derived. The typical numerical examples are given and compared with those obtained from numerically integral calculation. The results show that our method can significantly improve the numerical calculation efficiency. 相似文献
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WANG Zhaoying LIN Qiang NI Jie 《Chinese Journal of Lasers》2001,10(6):432-438
1 Introduction ItiswellknownthatthefundamentalGaussianbeamisnottheexactsolutionofMaxwell′sequations,butanapproximatesolutionofthewaveequationundertheconditionofslowly varyingenvelopeapproximation[1] .Theparaxialapproximationisnolongervalidwhenthebeamwai… 相似文献
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By using the methods of Hertz vector and angular spectrum transormation, the exact solution of non-paraxial elliptical Gaussion beam with general astigmatism based on Maxwell′s equations is obtained. We discussed its propagation characteristics. The results show that the orientation of the elliptical beam spot changes continuously as the beam propagates through isotropic media. Splitting or coupling of beam spots may occur for different initial spot size. This is very different from that of paraxial elliptical Gaussian beam. 相似文献
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Guoquan Zhou 《Optics Communications》2011,284(1):8-4135
Based on the angular spectrum representation of an arbitrary electromagnetic beam and the method of stationary phase, an analytically vectorial structure of a Gaussian beam diffracted by a phase aperture has been derived in the far-field. Moreover, the derivation is performed without any approximation. The analytical expressions of the energy flux of the TE term, the TM term, and the apertured Gaussian beam are also presented in the far-field, respectively. The influence of the phase delay on the energy flux distributions of the TE term, the TM term, and the apertured Gaussian beam is discussed in the far-field. 相似文献