A flat-field Mueller matrix imaging system with large field of view

Polarization imaging has shown the potential as a label-free tool in biomedical research due to its sensitivity to microstructures, especially the anisotropy analysis in pathological diagnosis. The digital pathology based on Mueller matrix systems has developed rapidly in recent years, and gradually progressed from qualitative to quantitative recognition. However, traditional critical illumination used in Mueller microscopes is likely to generate non-uniform projection accompanied by spatially varying irradiance, possibly due to unaligned optics, dust, nonuniform light sources, vignetting, etc. The non-uniform illumination results in artifacts in polarization images when stitching adjacent images to obtain a polarized image of the full sample, limiting the increase of the field of view (FOV). Therefore, a Mueller matrix microscope system with flat-field illumination and with motorized two-axis stage is proposed, we minimize the artifacts caused during splicing by uniform illumination, as well as increase the signal-to-noise (SNR) in the whole polarization images. The comparison of the real pathological sections under flat-field and wide-field illumination confirms the potential of large FOV imaging, which allows the structure of the sample to be presented more completely, laying the foundation for future pixel-level polarization digital pathology.