Measuring the Transmission Matrix of a scattering medium using Epi-Fluorescence light

TL;DR

This paper introduces a novel method to measure the transmission matrix of a scattering medium using fluorescence feedback, enabling focus control in reflection microscopy without accessing the far side of the scatterer.

Contribution

The method allows transmission matrix retrieval using fluorescence light as feedback in reflection geometry, eliminating the need for access to the distal side of the scatterer.

Findings

Enables focusing on the entire field of view after a single measurement

Works in reflection epi-illumination microscopy

Does not disturb the sample during measurement

Abstract

There are several methods to focus light behind a scattering medium, but very few use fluorescence light as feedback or can be used without access to the distal side of the scatterer. Among all the wave-front shaping techniques, retrieving the transmission matrix of a scattering material is the only one that allows for focusing on multiple spots after a single set of measurements. Here we propose a method to retrieve the transmission matrix of a scatterer using fluorescence light as feedback without access to the distal side. The advantage of this method is that it allows focusing on the whole field of view after a single matrix measurement without affecting the sample, making it suitable for reflection epi-illumination geometry microscopy.