Coherent enhancement of optical remission in diffusive media

TL;DR

This paper demonstrates that wavefront shaping can significantly enhance optical remission in diffusive media, improving sensitivity and penetration depth for non-invasive imaging applications.

Contribution

The study introduces a method to coherently enhance remission signals in diffusive media, combining experimental, numerical, and theoretical analysis to optimize wavefront control.

Findings

Achieved an order of magnitude remission enhancement

Demonstrated penetration depth up to 10 transport mean free paths

Predicted maximal remission enhancement with a theoretical model

Abstract

From the earth's crust to the human brain, remitted waves are used for sensing and imaging in a diverse range of diffusive media. Separating the source and detector increases the penetration depth of remitted light, yet rapidly decreases the signal strength, leading to a poor signal-to-noise ratio. Here, we experimentally and numerically show that wavefront shaping a laser beam incident on a diffusive sample enables an order of magnitude remission enhancement, with a penetration depth of up to 10 transport mean free paths. We develop a theoretical model which predicts the maximal-remission enhancement. Our analysis reveals a significant improvement in the sensitivity of remitted waves, to local changes of absorption deep inside diffusive media. This work illustrates the potential of coherent wavefront control for non-invasive diffuse-wave imaging applications, such as diffuse optical tomography and functional near-infrared spectroscopy.