Three-dimensional optical diffraction tomographic microscopy with optimal frequency combination with partially coherent illuminations

We demonstrate a three-dimensional (3D) optical diffraction tomographic technique with optimal frequency combination (OFC-ODT) for the 3D quantitative phase imaging of unlabeled specimens. Three sets of through-focus intensity images are captured under an annular aperture and two circular apertures with different coherence parameters. The 3D phase optical transfer functions (POTF) corresponding to different illumination apertures are combined to obtain an optimally synthesized frequency response, achieving high-quality, low-noise 3D reconstructions with imaging resolution up to the incoherent diffraction limit. Besides, the 3D imaging performance of annular illumination is explored and the expression of 3D POTF for arbitrary illumination pupils is derived and analyzed. It is shown that the phase-contrast washout effect in high-NA circular apertures can be effectively addressed by introducing a complementary annular aperture, which strongly boosts the phase contrast and improves the practical imaging resolution. To test the feasibility of the proposed OFC-ODT technique, the 3D refractive index reconstruction results based on a simulated 3D resolution target and experimental investigations of micro polystyrene bead and unstained biological samples are presented. Due to its capability of high-resolution 3D phase imaging as well as the compatibility with widely available commercial microscope, the OFC-ODT is expected to find versatile applications in biological and biomedical research.