Artifactless, lens-free coherent microscopy with quasi-3D scanning

We propose a quasi-3D scheme to solve imaging artifacts from the laser source for lens-free holographic imaging. The scheme includes three steps: background noise removal, image alignment and twin-image elimination. The sample moves along the lateral direction and the imaging sensor is sequentially placed at different axial distances for data recording. With this volume data, the artifacts from the laser source can be effectively mitigated. The experiments show that a pixel-level imaging resolution (1.55 µm) over a field-of-view larger than 20 mm² can be achieved. The experiments with biological samples, including kidney and intestine pathological slides of rats, validate that this technique can realize dramatic image contrast and resolution enhancements compared to conventional lens-free holographic methods. Our work provides a new framework to suppress laser source artifacts for holographic imaging. (paper)