Directional transport along an atomic chain

TL;DR

This paper investigates how to engineer atomic waveguides for directional light transport, demonstrating conditions for mode-to-mode transmission, reduced backscattering, and robustness to disorder, with implications for quantum photonics.

Contribution

It introduces a scattering-matrix formalism to analyze directional transport in atomic waveguides and explores the trade-offs between robustness and radiative losses.

Findings

Directional waveguides enable efficient outcoupling of light.

Reduced backscattering enhances robustness against disorder.

Directional waveguides are more resistant to localization but have higher radiative losses.

Abstract

Motivated by a recent prediction to engineer the dispersion relation of a waveguide constructed from atomic components [arXiv:2104.08121], we explore the possibility to create directional transport in an open, collective quantum system. The optical response of the atomic waveguide is characterized through a scattering-matrix formalism built upon theories of photoelectric detection that allows us to find the required conditions for directional mode-to-mode transmission to occur and be measured in an experimental setting. We find that directional waveguides allow for an efficient outcoupling of light by reducing backscattering channels at the edges. This reduced backscattering is seen to play a major role on the dynamics when disorder is included numerically. A directional waveguide is shown to be more robust to localization, but at the cost of increased radiative losses.