# Wide-field high-resolution 3D microscopy with Fourier ptychographic diffraction tomography

## TL;DR

Fourier ptychographic diffraction tomography (FPDT) is a computational 3D microscopy method that combines multiple low-resolution images with variable illumination to produce high-resolution, wide-field, depth-resolved 3D images of biological samples, surpassing traditional optical diffraction tomography.

## Contribution

This paper introduces FPDT, a novel 3D microscopy technique that reconstructs high-resolution, large-volume refractive index images from low-NA intensity measurements using a Fourier space stitching approach.

## Key findings

- Achieved 390nm lateral resolution and 899nm axial resolution.
- Provided billion-voxel 3D images of biological samples.
- Demonstrated high-throughput, label-free imaging over large fields of view.

## Abstract

We report a computational 3D microscopy technique, termed Fourier ptychographic diffraction tomography (FPDT), that iteratively stitches together numerous variably illuminated, low-resolution images acquired with a low-numerical aperture (NA) objective in 3D Fourier space to create a wide field-of-view (FOV), high-resolution, depth-resolved complex refractive index (RI) image across large volumes. Unlike conventional optical diffraction tomography (ODT) approaches that rely on controlled bright-field illumination, holographic phase measurement, and high-NA objective detection, FPDT employs tomographic RI reconstruction from low-NA intensity-only measurements. In addition, FPDT incorporates high-angle dark-field illuminations beyond the NA of the objective, significantly expanding the accessible object frequency. With FPDT, we present the highest-throughput ODT results with 390nm lateral resolution and 899nm axial resolution across a 10X FOV of 1.77mm2 and a depth of focus of ~20{\mu}m. Billion-voxel 3D tomographic imaging results of biological samples establish FPDT as a powerful non-invasive and label-free tool for high-throughput 3D microscopy applications.