Lensfree dynamic super-resolved phase imaging based on active micro-scanning

In this Letter, we present a new active micro-scanning-based imaging platform and associated super-resolution (SR) phase retrieval method in lensfree microscopy to achieve SR dynamic phase imaging. The samples are illuminated by a nearly coherent illumination system, where two orthogonal parallel plates are inserted into the light path and rotate to achieve controllable source micro-scanning, permitting sub-pixel shifts of the holograms on x- and y-axis directions independently. Then sequential low-resolution sub-pixel-shifted holograms are processed to enhance spatial resolution and reconstruct quantitative phase images of the sample simultaneously. The reconstruction result of the benchmark quantitative phase microscopy target (QPTTM) demonstrates a half-pitch lateral resolution of 775 nm across a large field-of-view of ∼29.84 mm2, surpassing 2.15 times that of the theoretical Nyquist–Shannon sampling resolution limit imposed by the pixel size of the imaging sensor (1.67 μm). The proposed approach is also evaluated by imaging unstained HeLa cells, suggesting it is a promising toolset for high-throughput monitoring and quantitative analysis of unlabeled biological samples.