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arXiv 0908.2523physics.optics
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嵌入相位奇点全息图对涡旋光束的变换

Transformation of Optical Vortex Beams by Holograms with Embedded Phase Singularity

A. Ya. Bekshaev, O. V. Orlinska

摘要:

从理论上研究了圆劳埃-高斯模入射的“叉形”全息图衍射光束的空间特性。衍射光束的复振幅分布可用库默尔光束或超几何高斯光束的模型来描述。在物理上,在大多数情况下,它的结构是在发散球面波的影响下形成的,发散球面波起源于光束空间轮廓中的不连续性或由全息图的凹槽分叉引起的其衍生物。这种波的存在是由近场衍射光束轮廓中的波纹结构和光束周边处的幂律振幅衰减来体现的。讨论了不激发发散波的条件。衍射光束携带螺旋波前位错(光学涡旋),其阶数等于入射光束方位角指数与全息图赋予的奇异性的拓扑荷的代数和。当上述总和为零时,输入光束的奇异性可以被治愈。在这种情况下,衍射光束可以在中心强度峰值中提供比高斯光束更好的能量集中,高斯光束的初始分布与入射光束的高斯包络重合。应用是可能的产生的光学涡旋光束与规定的属性和分析的光学涡旋光束在信息处理的问题。

英文摘要:

Spatial characteristics of diffracted beams produced by the "fork" holograms from incident circular Lauerre-Gaussian modes are studied theoretically. The complex amplitude distribution of a diffracted beam is described by models of the Kummer beam or of the hypergeometric-Gaussian beam. Physically, in most cases its structure is formed under the influence of the divergent spherical wave originating from the discontinuity in the beam spatial profile or its derivatives caused by the hologram's groove bifurcation. Presence of this wave is manifested by the ripple structure in the near-field diffracted beam profiles and in the power-law amplitude decay at the beam periphery. Conditions when the divergent wave is not excited are discussed. The diffracted beam carries a screw wavefront dislocation (optical vortex) whose order equals to algebraic sum of the incident beam azimuthal index and the topological charge of the singularity imparted by the hologram. The input beam singularity can be healed when the above sum is zero. In such cases the diffracted beam can provide better energy concentration in the central intensity peak than the Gaussian beam whose initial distribution coincides with the Gaussian envelope of the incident beam. Applications are possible for generation of optical-vortex beams with prescribed properties and for analyzing the optical-vortex beams in problems of information processing.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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