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 0.5μm and 0.84μrad, respectively.
© 2010 Optical Society of America
Original Manuscript: April 22, 2010
Revised Manuscript: July 11, 2010
Manuscript Accepted: July 15, 2010
Published: August 5, 2010
Haotong Ma, Fengjie Xi, Xiaolin Wang, Liang Liu, Yanxing Ma, Pu Zhou, Xiaojun Xu, Zejin Liu, and Xiuxiang Chu, "Simultaneous displacement and angular drift measurement based on defocus grating," Appl. Opt. 49, 4420-4426 (2010)