A method for generating double-ring-shaped vector beams
Chen Huan1, Ling Xiao-Hui2, Chen Zhi-Hong1, Li Qian-Guang1, Lv Hao1, Yu Hua-Qing1, Yi Xu-Nong1, †,
       

Slow axis spatial distributions of the PBP elements with (a) q = 0.5, (b) q = 1.0, and (c) q = 1.5.