Print Email Facebook Twitter Relative optical wavefront measurement in displacement measuring interferometer systems with sub-nm precision Title Relative optical wavefront measurement in displacement measuring interferometer systems with sub-nm precision Author Meskers, A.J.H. Voigt, D. Spronck, J.W. Faculty Mechanical, Maritime and Materials Engineering Department Precision and Microsystems Engineering Date 2013-07-19 Abstract Many error sources can affect the accuracy of displacement measuring interferometer systems. In heterodyne interferometry two laser source frequencies constitute the finally detected wavefront. When the wavefronts of these source frequencies are non-ideal and one of them walks off the detector, the shape of the detected wavefront will vary. This leads to a change in measured phase at the detector resulting in increased measurement uncertainty. A new wavefront measurement tool described in this publication measures the relative phase difference between the two wavefronts of the two source frequencies of a coaxial heterodyne laser source as used in commercial heterodyne interferometer systems. The proposed measurement method uses standard commercial optics and operates with the same phase measurement equipment that is normally used for heterodyne displacement interferometry. In the presented method a bare tip of a multimode fiber represents the receiving detection aperture and is used for locally sampling the wavefront during a line scan. The difference in phase between the beating frequency of the scanning fiber and a reference beating frequency that results from integration over the entire beam, is used for the reconstruction of the wavefront. The method shows to have a phase resolution in the order of ~25 pm or ~?/25000 for ? 632.8 nm, and a spatial resolution of ~60 µm at a repeatability better than 1 nm over one week. Subject OA-Fund TU Delft To reference this document use: http://resolver.tudelft.nl/uuid:80ffb5b8-4b0e-42e9-b249-c7b25303443b DOI https://doi.org/10.1364/OE.21.017920 Publisher Optical Society of America Source http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-21-15-17920 Source Optics Express, 21 (5), 2013 Part of collection Institutional Repository Document type journal article Rights © 2013 Optical Society of America Files PDF Meskers_2013.pdf 3.07 MB Close viewer /islandora/object/uuid:80ffb5b8-4b0e-42e9-b249-c7b25303443b/datastream/OBJ/view