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.