Open AccessMeasurement of the spatial coherence of extended light source by twin beams-interference method
Author(s) -
Tianlong Man,
Yuhong Wan,
Zhuqing Jiang,
Dayong Wang,
Shiquan Tao
Publication year - 2013
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.62.214203
Subject(s) - optics , degree of coherence , coherence (philosophical gambling strategy) , interferometry , interference (communication) , spatial coherence , coherence length , coherence theory , detector , physics , coherence time , ghost imaging , light field , beam (structure) , computer science , telecommunications , laser , channel (broadcasting) , superconductivity , quantum mechanics
The coherence of light source have been employed in many aspects, such as optical processing and optical coherence holography. For this reason it has attracted vast interest in developing quantitative methods for measuring the spatial coherence characteristics of an optical field. We propose a novel method for measuring the spatial coherence degree of optical fields based on the triangular interferometer. Spatially separated twin beams are formed by an interferometer, and the interferogram formed by the twin beams is captured by an image detector. Because the separation of the twin beams is related to the coordinate position of the input beam, a series of positions are sampled by moving a pinhole and corresponding interference patterns are recorded. Then the visibilities of the interference patterns are calculated for measuring the spatial coherence degree. Experimentally measured and theoretically calculated values of spatial coherence degree fit well. The measurement error is 3.8%. Experimental results show the method proposed here is effective, simple, and robust without any special optical elements.