Observation of open scattering channels

TL;DR

This study experimentally confirms the existence of open channels in a linear optical scattering system by observing the predicted bimodal distribution of transmission efficiencies, validating a key random matrix theory prediction.

Contribution

First experimental observation of the bimodal distribution of transmission efficiencies, confirming the existence of open channels in wave transport through disordered media.

Findings

Transmission efficiencies follow the predicted bimodal distribution.

Missing a single channel hampers detection of open channels.

Quantum-optical readout enables characterization of scattering systems.

Abstract

The existence of fully transmissive eigenchannels ("open channels") in a random scattering medium is a counterintuitive and unresolved prediction of random matrix theory. The smoking gun of such open channels, namely a bimodal distribution of the transmission efficiencies of the scattering channels, has so far eluded experimental observation. We observe an experimental distribution of transmission efficiencies that obeys the predicted bimodal Dorokhov-Mello-Pereyra-Kumar distribution. Thereby we show the existence of open channels in a linear optical scattering system. The characterization of the scattering system is carried out by a quantum-optical readout method. We find that missing a single channel in the measurement already prevents detection of the open channels, illustrating why their observation has proven so elusive until now. Our work confirms a long-standing prediction of random matrix theory underlying wave transport through disordered systems.