Optical phase conjugation with less than a photon per degree of freedom

TL;DR

This paper experimentally shows that optical phase conjugation can effectively focus light through scattering media with extremely low photon counts, enabling applications in deep tissue imaging and dynamic media.

Contribution

It demonstrates the feasibility of optical phase conjugation at photon levels below one per degree of freedom, expanding its potential use cases.

Findings

Intensity contrast equals total detected photons

Effective focusing at extremely low photon counts

Potential for deep tissue and dynamic media imaging

Abstract

We demonstrate experimentally that optical phase conjugation can be used to focus light through strongly scattering media even when far less than a photon per optical degree of freedom is detected. We found that the best achievable intensity contrast is equal to the total number of detected photons, as long as the resolution of the system is high enough. Our results demonstrate that phase conjugation can be used even when the photon budget is extremely low, such as in high-speed focusing through dynamic media, or imaging deep inside tissue.