title: In situ measurement of the topological charge of a perfect vortex using the phase shift method.
abstract: We propose a method to determine the topological charge (TC) of a perfect vortex. With the phase shift technique, the perfect vortex and its conjugate beam exactly overlap and interfere. Consequently, the TC of a perfect vortex is determined by counting the number of interference fringes. This proposed method enables in situ determination of the TC of the perfect vortex without the need for additional optical elements, and it is immune to environmental vibration and parasitic interference.
authors.forename: Haixiang
authors.initials: H
authors.lastname: Ma
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Li
authors.forename: Yuping
authors.initials: Y
authors.lastname: Tai
authors.forename: Hehe
authors.initials: H
authors.lastname: Li
authors.forename: Jingge
authors.initials: J
authors.lastname: Wang
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Tang
authors.forename: Yishan
authors.initials: Y
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.forename: Zhaogang
authors.initials: Z
authors.lastname: Nie