Iterative Kramers–Kronig method for non-interferometric quantitative phase imaging of large-phase objects

Quantitative phase imaging (QPI) is a vital label-free technique for visualizing transparent specimens. While non-interferometric QPI methods overcome the limitations of coherent interferometry, they often rely on restrictive object approximations (e.g., Born/Rytov), struggling with high-accuracy, single-shot retrieval of both absorption and large-phase features. To address this, we propose an iterative Kramers-Kronig QPI method (iKK-QPI) that enables high-accuracy large-phase retrieval beyond object approximations. Furthermore, by integrating a color-multiplexed illumination scheme, we develop a single-shot implementation termed SiKK, which simultaneously captures multi-angle intensity data using a color image sensor. The complex amplitude retrieved via KK relations serves as an initial value for iteration, enabling reconstruction of the object’s true absorption and phase. Experimental results validate the method’s effectiveness in high-throughput large-phase imaging, showcasing its significant potential for dynamic biological applications.