Yang-yue LI, Hui LIU, Zi-yang CHEN, Ji-xiong PU^*, and Bao-li YAO¹

College of Information Science and Engineering, Huaqiao University, Quanzhou, Fujian 362021, China
¹State Key Laboratory of Transient Optics Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, West Friendship Road 322, Xi'an 710068, China

(Received January 13, 2010; Accepted November 5, 2010)

The topological charge of integral vortex beams with a single circle of multipoints has previously been measured. In this work, we theoretically and experimental study the diffraction patterns of vortex beams of integral and fractional topological charges using a single circle and two circles of multipoint plates. It is found that the diffraction patterns are dependent not only on the multipoint plates, but also on the topological charge of the vortex beams. On the basis of this property, we can measure the topological charges of integral and fractional vortex beams.

Key words: vortex beams, multipoint plates, interference

^*E-mail address: jixiong@hqu.edu.cn