Tomographic diffractive microscopy of living cells based on a common-path configuration

We demonstrate a common-path tomographic diffractive microscopy technique for three-dimensional (3D) refractive-index (RI) imaging of unstained living cells. A diffraction grating is utilized to generate a reference beam that traverses a blank region of the sample in a common-path off-axis interferometry setup. Single-shot phase images captured at multiple illumination angles are used for 3D RI reconstruction based on optical diffraction tomography. The common-path configuration shows lower temporal phase fluctuations and better RI resolution than a Mach–Zehnder configuration. 3D subcellular RI distributions of live HeLa cells are quantified.