Optical properties of an atomic ensemble coupled to a band edge of a photonic crystal waveguide

TL;DR

This paper investigates how an atomic ensemble coupled to a photonic crystal waveguide exhibits unique optical behaviors, including altered transmission spectra and nonlinear responses, with potential applications in quantum optics.

Contribution

It demonstrates how long-range interactions mediated by a photonic crystal waveguide fundamentally change the optical properties of atomic ensembles, revealing new regimes of linear and nonlinear behavior.

Findings

Multiple transmission dips in the spectrum characterize the linear regime.

The system can behave like a single two-level atom in the nonlinear regime.

The results are relevant for upcoming atom-photonic crystal waveguide experiments.

Abstract

We study the optical properties of an ensemble of two-level atoms coupled to a 1D photonic crystal waveguide (PCW), which mediates long-range coherent dipole-dipole interactions between the atoms. We show that the long-range interactions can dramatically alter the linear and nonlinear optical behavior, as compared to a typical atomic ensemble. In particular, in the linear regime, we find that the transmission spectrum reveals multiple transmission dips, whose properties we show how to characterize. In the many-photon regime the system response can be highly non-linear, and under certain circumstances the ensemble can behave like a single two-level system, which is only capable of absorbing and emitting a single excitation at a time. Our results are of direct relevance to atom-PCW experiments that should soon be realizable.