18 June 2007 Vertical scanning interferometry with a mixed-coherence light source
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Micro interferometers are powerful optical instruments for 3D-surface metrology that usually adopt one of two different concepts for the data acquisition: the Phase Shifting Interferometry (PSI) and the Vertical Scanning Interferometry (VSI). In our approach we generate an illumination with mixed coherence characteristics by superposition of light beams from a broadband incandescent lamp and from a laser source. With a novel data evaluation technique we are able to obtain with a single vertical scan a surface profile that has the resolution and the accuracy of PSI and the measurement range of VSI. As an example, we present a surface that has a step of about 1,3&mgr;m and a shallow hole of about 0.1&mgr;m depth that could be entirely surveyed in a single vertical scan.
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Gabor Molnar, Gabor Molnar, Rainer Tutsch, Rainer Tutsch, "Vertical scanning interferometry with a mixed-coherence light source", Proc. SPIE 6616, Optical Measurement Systems for Industrial Inspection V, 661608 (18 June 2007); doi: 10.1117/12.725108; https://doi.org/10.1117/12.725108

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