中国物理B ›› 2008, Vol. 17 ›› Issue (5): 1743-1751.doi: 10.1088/1674-1056/17/5/034

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Composite optical vortices in noncollinear Laguerre--Gaussian beams and their propagation in free space

吕百达1, 程 科2, 刘普生2   

  1. (1)Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064, China; (2)Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064, China
  • 收稿日期:2007-07-03 修回日期:2007-09-09 出版日期:2008-05-20 发布日期:2008-05-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10574097).

Composite optical vortices in noncollinear Laguerre--Gaussian beams and their propagation in free space

Cheng Ke(程科), Liu Pu-Sheng(刘普生), and Lü Bai-Da(吕百达)†   

  1. Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064, China
  • Received:2007-07-03 Revised:2007-09-09 Online:2008-05-20 Published:2008-05-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10574097).

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摘要： Taking two Laguerre--Gaussian beams with topological charge l=±1 as an example, this paper studies the composite optical vortices formed by two noncollinear Laguerre--Gaussian beams with different phases, amplitudes, waist widths, off-axis distances, and their propagation in free space. It is shown by detailed numerical illustrative examples that the number and location of composite vortices at the waist plane are variable by varying the relative phase β, amplitude ratio η, waist width ratio \textitζ, or off-axis distance ratio μ. The net topological charge lnet is not always equal to the sum lsum of charges of the two component beams. The motion, creation and annihilation of composite vortices take place in the free-space propagation, and the net charge during the propagation remains unchanged and equals to the net charge at the waist plane.

关键词: composite optical vortex, Laguerre--Gaussian beam, topological charge, creation and annihilation

Abstract: Taking two Laguerre--Gaussian beams with topological charge l=±1 as an example, this paper studies the composite optical vortices formed by two noncollinear Laguerre--Gaussian beams with different phases, amplitudes, waist widths, off-axis distances, and their propagation in free space. It is shown by detailed numerical illustrative examples that the number and location of composite vortices at the waist plane are variable by varying the relative phase $\beta$, amplitude ratio $\eta$, waist width ratio $\xi$, or off-axis distance ratio $\mu$. The net topological charge lnet is not always equal to the sum lsum of charges of the two component beams. The motion, creation and annihilation of composite vortices take place in the free-space propagation, and the net charge during the propagation remains unchanged and equals to the net charge at the waist plane.

Key words: composite optical vortex, Laguerre--Gaussian beam, topological charge, creation and annihilation

中图分类号:  (Wave optics)

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