两束离轴高斯光束干涉场中的横向光涡旋

Transversal optical vortex in the interference field of two off-axis Gaussian beams

研究了两束离轴高斯光束干涉场中的波前结构以及横向光涡旋.研究表明干涉场中的相位鞍点以及涡旋点的位置与光束的离轴参数、束腰宽度、相位以及相对振幅有关.相位鞍点既可位于涡旋点的内侧,也可以位于涡旋点的外侧,且控制参数取一定值时,相位鞍点将与涡旋点重合.对于离轴光束,XZ平面两侧的相位鞍点与涡旋点相遇时所对应的控制参数并不相同,且XZ平面上相位鞍点相遇时所对应x值,一般情况下与涡旋点相遇时所对应的x值不相同.

The structure of the wavefront and transversal optical vortices in an interference field of two off-axis Gaussian beams is studied. It is shown that the positions of phase saddles and vortices depend on the off-axis parameter, beam width, phase and relative amplitude of beams. The saddle can be located inside or outside the vortices. For a certain value of the governing parameter, the saddle point coincides with the vortex. For off-axis beams, the encounters of the saddle point and vortex on both sides in the XZ cross-section do not occur at the same governing parameter η. Moreover, the x value corresponding to the encounter of saddle points is not equal to the x value corresponding to the encounter of vortices.