Breaking the mid-spatial-frequency noise floor to sub-nanometer in Fizeau interferometry via anisotropic spatial-coherence engineering

作者：Xinming Li, Shaojing Peng, Zhaorui Xu, Jian Bai, Lan Wu, Yibing Shen, Dong Liu · 发表于：Optics Letters · 年份：2025 · DOI：10.1364/ol.567026 · 被引用次数：3 · 研究领域：Optical Coherence Tomography Applications、Optical measurement and interference techniques、Digital Holography and Microscopy

Anisotropic spatial-coherence engineering via illumination modulation is demonstrated to selectively suppress the mid-spatial-frequency (MSF) noise in interferometry. Using a 3D spatial-coherence model, we prove the superiority of a synthetic ring source with anisotropic spatial-coherence function in Fizeau systems and reveal characteristic residual noise patterns of a zero-order Bessel function. A noise transfer function (NTF) is proposed as an essential complement to the instrument transfer function (ITF) framework, enabling quantitative assessment of noise suppression across all spatial frequencies. With the proposed method, NTF < 0.4 and ITF > 0.8 within 9.1 lp/mm are achieved in a 632.8-nm, 4-in. Fizeau interferometer, breaking the MSF noise floor to sub-1 nm. This work provides a rapid, full-aperture measurement solution for MSF errors on high-precision optical surfaces.