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Conference 11889 > Paper 11889-7
Paper 11889-7

Measurement of transmitted wavefront error and homogeneity with a low-coherence interferometer

In person: 18 October 2021 • 10:50 AM - 11:10 AM EDT


We describe high-precision measurements of the transmitted wavefront error and refractive index homogeneity of glass plates using a low-coherence interferometer in a downward-looking configuration. With the low-coherence illumination there are no spurious interference fringes even for a plane-parallel sample. Unbiased results are obtained by using a combination of four different measurement steps. The measurement performance and repeatability are shown for the low-coherence interferometer OptoFlat with a special fixture incorporating sample holder and return mirror. Its ease of handling and supporting software-based user guidance through the measurement steps greatly facilitate wavefront and homogeneity measurements in the optics shop.


InterOptics, LLC (United States)
As optical systems engineer Klaus Freischlad was, over the last 30 years, the technical lead in the design and development of numerous instruments for optical metrology. The applications of these products include the topography measurements of optical lenses, semiconductor wafers, magnetic storage disks, and microscopic surface features in a variety of industries. With degrees in Physics and Optical Sciences, he worked at renowned optical companies Carl Zeiss, ADE Phase Shift, and Zygo. In 2007 he was co-founder of a Tucson startup company, Zemetrics, Inc., in optical interferometric Metrology, and in 2016 he co-founded Interoptics LLC. Dr. Klaus Freischlad holds 13 patents in optical metrology technology.
InterOptics, LLC (United States)