Quantitative phase imaging based on the transport-of-intensity equation using white-light diffraction phase microscopy

We present a compact quantitative phase imaging (QPI) system based on a white-light diffraction phase microscopy (wDPM) configuration. This system is capable of capturing wide-field digital holograms (DH) under low-coherence illumination while maintaining high spatiotemporal sensitivity and stability. Our cost-effective module is compatible with imaging devices such as the bright-field microscope, simplifying the QPI process significantly in a label-free manner. Additionally, it facilitates a detailed comparison between the wDPM, transport-of-intensity equation (TIE) phase retrieval methods, and other QPI methods, serving as a multimodal platform. Moreover, we achieved direct QPI of a single-shot DH through multichannel wavefront reconstruction, acquisition of chromatic aberration, and implementation of the TIE method. This approach circumvents the need for cumbersome phase unwrapping (PU) and aberration correction procedures typical in wDPM, highlighting the potential of QPI using the proposed wDPM-TIE method. Furthermore, to address the halo effect inherent in wDPM, we reconstructed the reference beam wavefront through TIE and utilized it to mitigate the halo artifacts. Simulation and comparative experimental results affirm the feasibility, accuracy, and dynamic QPI capability of the proposed configuration together with the wDPM-TIE QPI method in both micro-optics and bio-imaging, showcasing nanometer-level spatial and temporal noise.