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

• 来源期刊: 中国物理B（英文版）
• 关键词: composite optical vortex Laguerre-Gaussian beam topological charge creation and annihilation
• 年，卷（期）: 2008,（5）
• 页码范围: 1743-1751
• 页数: 9页
• 语种: 英文

摘要

Taking two Laguerre-Gauasian 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 flee 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 ξ,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.