High-contrast, label-free, specific-colored 3D bioimaging via polarization-enhanced intensity diffraction tomography

Abstract

Label-free intensity diffraction tomography (IDT) has attracted considerable attention for 3D biological imaging due to its label-free capability, minimal system complexity, and reduced coherent noise. However, like other phase contrast techniques, IDT suffers from limited contrast and lacks molecular specificity compared to fluorescence imaging. To address these limitations, we present polarization-enhanced intensity diffraction tomography (PeIDT), which utilizes annular illumination scanning and a polarization analyzer. In the proposed PeIDT, the reconstructed refractive index (RI) is extended to a vector similar to a Stokes vector (i.e., n_I, n_Q, and n_U), termed polarization-sensitive vector RI (PsRI), carrying specific polarization information about the biological sample. Furthermore, by fusing these components in the HSV method, PeIDT provides polarization-specific enhanced 3D reconstructions. Simulations and experiments on phantom cells, Paramecium, oral epithelial cells, and mouse liver tissue validate the method’s capability for high-contrast, label-free, volumetric imaging of complex biological specimens.