Quasi-common-optical-path heterodyne grating interferometer for displacement measurement

H. L. Hsieh, J. Y. Lee, W. T. Wu, J. C. Chen, R. Deturche, G. Lerondel

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33 Scopus citations


A novel heterodyne grating interferometer based on a quasi-common-optical- path design is proposed for displacement measurement. The quasi-common-optical- path design relies on the phase shift between the zeroth and first diffraction grating orders which have been rotated in polarization using a half-wave plate. We achieved a measurement resolution better than 3 nm with a system stability of less than 14 nm over 1 h. We discussed the performances of the system addressing the effect of dominant errors, namely grating pitch, frequency mixing, polarization mixing and polarization-frequency mixing. While the theoretically quasi-common-optical-path heterodyne grating system allows for sub-nanometer resolution, we found that the measurement resolution here is limited by the displacement stage. Relying on heterodyne interferometric phase measurement combined with quasi-common-optical configuration, the proposed and demonstrated method has the advantages of high measurement resolution, relatively straightforward operation and high stability.

Original languageEnglish
Article number115304
JournalMeasurement Science and Technology
Issue number11
StatePublished - Nov 2010


  • Grating
  • Heterodyne


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