Open AccessTwo-channel six degrees of freedom grating-encoder for precision-positioning of sub-components in synthetic-aperture optics
Author(s) -
Kangning Yu,
Junhao Zhu,
Weihan Yuan,
Qian Zhou,
Gaopeng Xue,
Guanhao Wu,
Xiaohao Wang,
Xinghui Li
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.427307
Subject(s) - optics , grating , encoder , physics , interferometry , diffraction grating , rotary encoder , optical path , aperture (computer memory) , computer science , acoustics , operating system
We investigate a novel two-channel grating encoder that can perform simultaneous measurements of six-degree-of-freedom (DOF) motions of two adjacent sub-components of synthetic-aperture optics such as pulse-compression gratings(PCGs) and telescope-primary mirrors. The grating encoder consists of a reading head and two separate gratings, which are attached to the back of the sub-components, respectively. The reading head is constructed such that there two identical optical probes can share the same optical components. The two probes are guided to hit each of the two gratings and can detect six-DOF motions simultaneously and independently. For each probe, the incident beam propagates through both a three-axes grating interferometry module and a three-axes diffraction integrated autocollimator-module, which detects translational and rotational movement, respectively. By combining the two modules it is possible to perform six-DOF measurement for a single point. The common-path configuration of the two probes enable identical responses to environmental variation, which ensures high accuracy.