title: Propagation of Riemann-Silberstein vortices through an astigmatic lens.
abstract: The propagation of Riemann-Silberstein (RS) vortices for Gaussian vortex beams with topological charges m=+1 through a lens is studied. It is shown that if there is an ideal lens, a RS vortex and a circular edge dislocation appear for Gaussian on-axis vortex beams, while only RS vortices take place for Gaussian off-axis vortex beams. In the presence of an astigmatic lens, there exist RS vortices but no edge dislocations for both Gaussian on-axis and off-axis beams. By varying the astigmatic coefficient, the off-axis parameter, and the propagation distance, the motion, creation, and annihilation of vortices may take place, and in the process, the total topological charge of RS vortices remains unchanged.
authors.affiliation: School of Physics and Electrical Engineering, Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin, Sichuan 644000, China. yibinchent@sina.com
authors.forename: Haitao
authors.initials: H
authors.lastname: Chen
authors.forename: Zenghui
authors.initials: Z
authors.lastname: Gao
authors.forename: Huajun
authors.initials: H
authors.lastname: Yang
authors.forename: Xuefang
authors.initials: X
authors.lastname: Zou
authors.forename: Fanhou
authors.initials: F
authors.lastname: Wang