Improved quantitative phase contrast in self-interference digital holographic microscopy and sensing dynamic refractive index changes of the cytoplasm using internalized microspheres as probes

In self-interference digital holographic microscopy (DHM), scattering patterns that are induced by coherent laser light affect the resolution for the detection of optical path length changes. We present a simple and efficient approach for the reduction of coherent disturbances in quantitative DHM phase images by amplitude and phase modulation of the sample illumination. The performance of the method in quantitative phase imaging of living cells is illustrated. Moreover, the application of self-interference DHM for sensing of dynamic refractive index changes of adherent cells is demonstrated. Therefore, silica microspheres are used in living cells as optical probes to determine the refractive index of the cytoplasm from single quantitative phase images.