High-resolution quantitative phase imaging via vortex beam speckle illumination.

This study introduces a vortex beam speckle imaging system for quantitative phase imaging (QPI) with high lateral resolution. By introducing vortex beams for non-diffracting speckle field regulation, the speckle size can be significantly reduced from 116.32 μm to 11.07 μm. With these advantages, the proposed imaging system has shown 1.52 folds of lateral resolution improvement compared to a traditional coherent imaging system. Furthermore, the intensity signal-to-noise ratio of the imaging system has also been improved from 13.26 dB to 30.62 dB. Transport-of-intensity equation (TIE) phase retrieval algorithms were applied to standard quantitative phase targets, and red blood cell samples were used to demonstrate the system's precise phase retrieval capability, indicating its potential applications for label-free, non-invasive biomedical imaging.