Robust wavefront sensing method for reflective optical surfaces based on reference light modulation and total variation regularization

Ptychographic coherent diffraction imaging has been proven effective for measuring reflective optical surfaces. However, its high scanning overlap requirements make it inefficient and cumbersome. This study introduces a lens-free technique that uses reference light coding for more efficient and accurate reflective surface topography measurement. The proposed extended coherent interferometry modulation imaging (ER-CIMI) algorithm measures reflected wavefront by adjusting the reference light phase and applying amplitude constraints on the interference-derived speckle map. An optimized optical path design separates objects and detection lights to minimize detection light imperfections. Additionally, a phase-recovery model with total variation regularization and sparse constraints enhances noise robustness. Numerical simulations and surface measurements confirm the method's efficacy. This method is expected to be applied to high-precision optical surface and microstructure measurements.