Structured illumination optical diffraction tomography with beam-propagation-based reconstruction

Optical diffraction tomography (ODT) can reconstruct the 3D refractive index (RI) distribution of a sample, yet it faces several challenges, such as the missing cone problem and the assumption of single scattering. Herein, we implemented 3D RI imaging by combining structured-illumination-based digital holographic microscopy (SI-DHM) with beam propagation method (BPM) based reconstruction. It is found that the BPM-based reconstruction method can provide a 3D RI map with higher accuracy and a five-fold improved signal-to-noise (SNR) ratio. Meanwhile, the BPM-based method works with a small number of illumination angles, for instance, 15 illumination angles can yield a 3D RI image with a SNR = 77 dB. We envisage that the proposed technique will be widely applied for the high-resolution, label-free, and high-contrast 3D RI imaging of biological samples.