Multi-Spectral Reflection Matrix for Ultra-Fast 3D Label-Free Microscopy

TL;DR

This paper introduces a multi-spectral reflection matrix technique that enhances 3D label-free microscopy, enabling real-time, high-resolution imaging of biological tissues with improved depth and speed.

Contribution

It presents a novel multi-spectral matrix approach with sparse illumination and interferometry, allowing fast, high-resolution 3D imaging without traditional aberration correction methods.

Findings

Achieved 290 nm resolution in 3D imaging of human cornea

Demonstrated 1 Hz frame rate for real-time imaging

Enabled deep tissue inspection with improved image quality

Abstract

Label-free microscopy exploits light scattering to obtain a three-dimensional image of biological tissues. However, light propagation is affected by aberrations and multiple scattering, which drastically degrade the image quality and limit the penetration depth. Multi-conjugate adaptive optics and time-gated matrix approaches have been developed to compensate for aberrations but the associated frame rate is extremely limited for 3D imaging. Here we develop a multi-spectral matrix approach to solve these fundamental problems. Based on a sparse illumination scheme and an interferometric measurement of the reflected wave-field at multiple wavelengths, the focusing process can be optimized in post-processing for any voxel by addressing independently each frequency component of the reflection matrix. A proof-of-concept experiment demonstrates the three-dimensional image of an opaque human cornea over a 0.1 mm$^3$-field-of-view at a 290 nm-resolution and a 1 Hz-frame rate. This work paves the way towards a fully-digital microscope allowing real-time, in-vivo, quantitative and deep inspection of tissues.