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

H. L. Hsieh (1) , J. Y. Lee (1) , W. T. Wu (1) , J. C. Chen (1) , Régis Deturche (2) , Gilles Lerondel (2)

1 NCU - National Central University [Taiwan]
2 LNIO - Laboratoire de Nanotechnologie et d'Instrumentation Optique

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.

Domains: Optics [physics.optics]; Instrumentation and Detectors [physics.ins-det]

H. L. Hsieh, J. Y. Lee, W. T. Wu, J. C. Chen, Régis Deturche, et al.. Quasi-common-optical-path heterodyne grating interferometer for displacement measurement. Measurement Science and Technology, 2010, 21 (11), pp.115304. ⟨10.1088/0957-0233/21/11/115304⟩. ⟨hal-02445599⟩