A method to expand the dynamic range for a Shack–Hartmann wavefront sensor (SHWFS) is proposed. Namely, a holographic Shack–Hartmann wavefront sensor (H-SHWFS) is proposed. In the the H-SHWFS, a microhologram array, which consists of independent small phase holograms, is used instead of a microlens array.

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Approximated wavefronts obtained by (a) the proposed and (b) the conventional methods in numerical simulations.

Reference
  • Yusuke Saita, Hironobu Shinto, and Takanori Nomura, "Holographic Shack–Hartmann wavefront sensor based on the correlation peak displacement detection method for wavefront sensing with large dynamic range," Optica 2, 411-415 (2015).