Two-probe optical encoder for absolute positioning of precision stages by using an improved scale grating Li, Xinghui ; Wang, Huanhuan ; Ni, Kai ; Zhou, Qian ; Mao, Xinyu ; Zeng, Lijiang ; Wang, Xiaohao ; Xiao, Xiang Abstract Publication: Optics Express Pub Date: September 2016 DOI: 10.1364/OE.24.021378 Bibcode: 2016OExpr..2421378L