Quantitative Phase Contrast Microscopy with Optimized Partially Coherent Illumination

This paper presents a partially coherent illumination quantitative phase contrast microscopic (PCI-QPCM) prototype. In the PCI-QPCM prototype, the light scattered by a rotating diffuser is coupled into a multi-mode fiber, and the output light is used as the illumination for PCI-QPCM. The illumination wave has a constrained spectrum with a diameter of tens of micrometers, which can reduce speckle noise and will not broaden the dc term of the object wave. In the Fourier plane of the object wave, grating-masked phase shifters generated by a spatial light modulator (SLM) allow for measuring the intensity of the undiffracted and diffracted components of the object wave, as well as the phase-shifted interference patterns of the two. Quantitative phase images can be reconstructed from the recorded intensity images. The proposed PCI-QPCM was demonstrated with quantitative phase imaging of a transparent waveguide and a phase-step sample.