  We present a multimodal approach for measuring the three-dimensional (3D)
refractive index (RI) and fluorescence distributions of live cells by combining
optical diffraction tomography (ODT) and 3D structured illumination microscopy
(SIM). A digital micromirror device is utilized to generate structured
illumination patterns for both ODT and SIM, which enables fast and stable
measurements. To verify its feasibility and applicability, the proposed method
is used to measure the 3D RI distribution and 3D fluorescence image of various
samples, including a cluster of fluorescent beads, and the time-lapse 3D RI
dynamics of fluorescent beads inside a HeLa cell, from which the trajectory of
the beads in the HeLa cell is analyzed using spatiotemporal correlations.
