title: Simultaneous displacement and angular drift measurement based on defocus grating.
abstract: We propose and demonstrate a displacement and angular drift simultaneous measurement technique based on a defocus grating. The displacement and angular drift of the incident beam can be detected by monitoring the movements of +/-1 diffraction order spots of the defocus grating. The relationship between drift of the incident beam and movements of +/-1 diffraction order spots is studied in detail. Compared with other methods, this technique eliminates the requirement of two or more detecting systems for measuring displacement and angular drift simultaneously. The proof-of-principle experiment shows that the root-mean-square errors of displacement and angular drift measurements are less than 0.5 microm and 0.84 microrad, respectively.
authors.affiliation: College of Photon-Electron Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073, China.
authors.forename: Haotong
authors.initials: H
authors.lastname: Ma
authors.forename: Fengjie
authors.initials: F
authors.lastname: Xi
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Liu
authors.forename: Yanxing
authors.initials: Y
authors.lastname: Ma
authors.forename: Pu
authors.initials: P
authors.lastname: Zhou
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Xu
authors.forename: Zejin
authors.initials: Z
authors.lastname: Liu
authors.forename: Xiuxiang
authors.initials: X
authors.lastname: Chu