Parallel synthetic aperture transport-of-intensity diffraction tomography with annular illumination

Transport-of-intensity diffraction tomography (TIDT) is a recently developed label-free computational microscopy technique that retrieves high-resolution three-dimensional (3D) refractive index (RI) distribution of biological speci-mens from 3D intensity-only measurements. However, the non-interferometric synthetic aperture in TIDT is gen-erally achieved sequentially through the acquisition of a large number of through-focus intensity stacks captured at different illumination angles, resulting in a very cum-bersome and redundant data acquisition process. To this end, we present a parallel implementation of a synthetic aperture in TIDT (PSA-TIDT) with annular illumination. We found that the matched annular illumination provides a mirror-symmetric 3D optical transfer function, indicating the analyticity in the upper half-plane of the complex phase function, which allows for recovery of the 3D RI from a sin-gle intensity stack. We experimentally validated PSA-TIDT by conducting high-resolution tomographic imaging of var-ious unlabeled biological samples, including human breast cancer cell lines (MCF-7), human hepatocyte carcinoma cell lines (HepG2), Henrietta Lacks (HeLa) cells, and red blood cells (RBCs).(c) 2023 Optica Publishing Group

Automated summary

Transport-of-intensity diffraction tomography (TIDT) is a label-free computational microscopy technique that retrieves high-resolution 3D refractive index distribution of biological specimens from intensity measurements. The conventional sequential acquisition process in TIDT is cumbersome and redundant. Therefore, a parallel implementation of synthetic aperture in TIDT (PSA-TIDT) with annular illumination is proposed, which allows for the recovery of 3D refractive index from a single intensity stack. Experimental validation of PSA-TIDT is conducted on various unlabeled biological samples.