Open AccessLong focal-length measurement using divergent beam and two gratings of different periods
Author(s) -
Jia Luo,
Jian Bai,
Jinchun Zhang,
Congcong Hou,
Kaiwei Wang,
Xiyun Hou
Publication year - 2014
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.22.027921
Subject(s) - optics , collimated light , beam expander , beam (structure) , repeatability , interferometry , focal length , aperture (computer memory) , grating , diffraction grating , talbot effect , physics , materials science , laser beams , lens (geology) , laser , mathematics , statistics , acoustics
A new accurate method for long focal-length measurement based on Talbot interferometry is proposed. A divergent beam and two Ronchi gratings of different periods are employed, as the alternative of the collimated beam and two identical gratings, to achieve higher measurement accuracy. Moreover, with divergent beam, lenses of large aperture can be easily measured without scanning, which is required when it comes to traditional collimated beam. Numerical analysis and experiments were carried out. The results demonstrate the proposed method features remarkably high accuracy and repeatability.