Efficient live cell imaging requires low doses of lights and ideally non labelled cells, to make sure that markers do not interfere with the cell structure and habits. Quantitative phase imaging is a great tool for these experiments, as it uses very low light doses and does not require externally introduced labels. Especially interesting are common-path straightforward configurations, as they can even work with light sources with low temporal coherence. Our previously introduced grating-deployed common-path QPI system is a great example of such systems, especially since the only modification that it requires, compared to classical brightfield microscope, is the addition of the diffraction grating. The camera records the total shear interference of the conjugate object beams as a self-referenced hologram after grating is used to divide the beams. As a result, it is possible to modify the temporal coherence and suppress coherent artifacts and related noise.. In this work we show the quantitative characterization of the grating-based common-path QPI system and the impact it has on the obtained results. We compare the illumination that utilizes SLED and laser light sources. We use phase resolution targets to evaluate the spatial resolution and phase sensitivity.
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