Spatially resolved contrast measurement of diffractive micromirror arrays

Cornelius Sicker; Jörg Heber; Dirk Berndt; Florian Rückerl; Jean-Yves Tinevez; Spencer Shorte; Michael Wagner; Harald Schenk

doi:10.1117/12.2076921

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27 February 2015 Spatially resolved contrast measurement of diffractive micromirror arrays

Cornelius Sicker, Jörg Heber, Dirk Berndt, Florian Rückerl, Jean-Yves Tinevez, Spencer Shorte, Michael Wagner, Harald Schenk

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Proceedings Volume 9375, MOEMS and Miniaturized Systems XIV; 93750D (2015) https://doi.org/10.1117/12.2076921
Event: SPIE OPTO, 2015, San Francisco, California, United States

Abstract

Diffractive micromirror arrays (MMA) are a special class of optical MEMS, serving as spatial light modulators (SLM) that control the phase of reflected light. Since the surface profile is the determining factor for an accurate phase modulation, high-precision topographic characterization techniques are essential to reach highest optical performance. While optical profiling techniques such as white-light interferometry are still considered to be most suitable to this task, the practical limits of interferometric techniques start to become apparent with the current state of optical MEMS technology. Light scatter from structured surfaces carries information about their topography, making scatter techniques a promising alternative. Therefore, a spatially resolved scatter measurement technique, which takes advantage of the MMA’s diffractive principle, has been implemented experimentally. Spectral measurements show very high contrast ratios (up to 10 000 in selected samples), which are consistent with calculations from micromirror roughness parameters obtained by white-light interferometry, and demonstrate a high sensitivity to changes in the surface topography. The technique thus seems promising for the fast and highly sensitive characterization of diffractive MMAs.

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Cornelius Sicker, Jörg Heber, Dirk Berndt, Florian Rückerl, Jean-Yves Tinevez, Spencer Shorte, Michael Wagner, and Harald Schenk "Spatially resolved contrast measurement of diffractive micromirror arrays", Proc. SPIE 9375, MOEMS and Miniaturized Systems XIV, 93750D (27 February 2015); https://doi.org/10.1117/12.2076921

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