Computational 3D microscopy with optical coherence refraction tomography

TL;DR

This paper introduces 3D optical coherence refraction tomography (OCRT), a computational method that enhances OCT imaging by reducing speckle noise and improving resolution through multi-angle data synthesis, enabling detailed 3D microscopy.

Contribution

The work presents a novel optical design and computational approach that extends OCT to produce high-resolution, speckle-reduced 3D images without sample movement, revealing new biological features.

Findings

OCRT reduces speckle noise in OCT images.

OCRT enhances lateral resolution in 3D reconstructions.

OCRT reveals features in biological samples not seen with conventional OCT.

Abstract

Optical coherence tomography (OCT) has seen widespread success as an in vivo clinical diagnostic 3D imaging modality, impacting areas including ophthalmology, cardiology, and gastroenterology. Despite its many advantages, such as high sensitivity, speed, and depth penetration, OCT suffers from several shortcomings that ultimately limit its utility as a 3D microscopy tool, such as its pervasive coherent speckle noise and poor lateral resolution required to maintain millimeter-scale imaging depths. Here, we present 3D optical coherence refraction tomography (OCRT), a computational extension of OCT which synthesizes an incoherent contrast mechanism by combining multiple OCT volumes, acquired across two rotation axes, to form a resolution-enhanced, speckle-reduced, refraction-corrected 3D reconstruction. Our label-free computational 3D microscope features a novel optical design incorporating a parabolic mirror to enable the capture of 5D plenoptic datasets, consisting of millimetric 3D fields of view over up to $\pm75^\circ$ without moving the sample. We demonstrate that 3D OCRT reveals 3D features unobserved by conventional OCT in fruit fly, zebrafish, and mouse samples.