Time-multiplexed structured illumination using a DMD for optical diffraction tomography

We present a novel illumination control technique for optical diffraction tomography (ODT). Various spatial frequencies of beam illumination were controlled by displaying time-averaged sinusoidal patterns using a digital micromirror device (DMD). Compared to the previous method using binary Lee holograms, the present method eliminates unwanted diffracted beams which may deteriorate the image quality of the ODT. We demonstrated the capability of the present method by reconstructing three-dimensional refractive index (RI) distributions of various samples, with high RI sensitivity (\sigma_\Delta n = 3.15 +/- 10-4), and reconstructing 3-D RI tomograms of biological samples, which provided quantitative biochemical and morphological information about the samples.