3D intensity and phase imaging from light field measurements in an LED array microscope

TLDR

Realizing high resolution across large volumes is challenging for 3D imaging techniques with high-speed acquisition. The authors present a new method for 3D intensity and phase recovery from 4D light field measurements, aiming to enhance resolution through Fourier ptychography. The method refocuses the light field via geometric optics, integrates phase retrieval and diffraction correction, employs dark-field imaging to surpass the objective’s diffraction limit laterally and improve axial resolution, and reconstructs the 3D complex transmittance with a multislice coherent model using data from an LED array microscope with computational illumination for rapid angular scanning. We demonstrate the method with thick biological samples in a modified commercial microscope, indicating the technique’s versatility for a wide range of applications.

Abstract

Realizing high resolution across large volumes is challenging for 3D imaging techniques with high-speed acquisition. Here, we describe a new method for 3D intensity and phase recovery from 4D light field measurements, achieving enhanced resolution via Fourier ptychography. Starting from geometric optics light field refocusing, we incorporate phase retrieval and correct diffraction artifacts. Further, we incorporate dark-field images to achieve lateral resolution beyond the diffraction limit of the objective (5× larger NA) and axial resolution better than the depth of field, using a low-magnification objective with a large field of view. Our iterative reconstruction algorithm uses a multislice coherent model to estimate the 3D complex transmittance function of the sample at multiple depths, without any weak or single-scattering approximations. Data are captured by an LED array microscope with computational illumination, which enables rapid scanning of angles for fast acquisition. We demonstrate the method with thick biological samples in a modified commercial microscope, indicating the technique’s versatility for a wide range of applications.