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 (QPT) demonstrates a half-pitch lateral resolution of 775 nm across a large field-of-view of ∼29.84  mm, 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.