Polarization-dependent metasurface for vector Zernike wavefront sensing with increased dynamic range

Metasurfaces have unique properties that make them suitable for a variety of optical applications. Not only do metasurfaces allow a great deal of design flexibility by controlling phase, amplitude, and polarization of reflected or transmitted light, they are also manufactured using mature semiconductor microprocessing techniques. Here we demonstrate a metasurface that can increase the dynamic range of Zernike wavefront sensors (ZWSs) by introducing phase diversity between two orthogonal linear polarizations in the near-infrared. The metasurface works in transmission and consists of elliptically shaped amorphous silicon nanopillars on a fused silica substrate. Wavefront sensors play an important role in segmented-mirror telescopes and enable the precise alignment needed between the segments in order to provide high-quality observations. This work has near-term implications for ground-based telescopes and is of importance for current and future mission concept formulations for exoplanet direct detection and characterization.