Characterization of the angular memory effect of scattered light in biological tissues

TL;DR

This paper investigates how strong forward scattering in biological tissues extends the angular memory effect range, potentially enabling deeper optical imaging by exploiting angular correlations in scattered light.

Contribution

It demonstrates that forward scattering in neural tissues significantly enhances the angular memory effect range, surpassing previous limitations for imaging through scattering media.

Findings

Forward scattering extends the memory effect range by over an order of magnitude.

Enhanced memory effect could enable larger field-of-view in optical imaging.

Results are supported by measurements and simulations on neural tissues.

Abstract

High resolution optical microscopy is essential in neuroscience but suffers from scattering in biological tissues. It therefore grants access to superficial layers only. Recently developed techniques use scattered photons for imaging by exploiting angular correlations in transmitted light and could potentially increase imaging depths. But those correlations (`angular memory effect') are of very short range and, in theory, only present behind and not inside scattering media. From measurements on neural tissues and complementary simulations, we find that strong forward scattering in biological tissues can enhance the memory effect range (and thus the possible field-of-view) by more than an order of magnitude compared to isotropic scattering for $\sim$1\,mm thick tissue layers.