Interaction signatures and non-Gaussian photon states from a strongly driven atomic ensemble coupled to a nanophotonic waveguide

Abstract

We study theoretically a laser-driven one-dimensional chain of atoms interfaced with the guided optical modes of a nanophotonic waveguide. The period of the chain and the orientation of the laser field can be chosen such that emission occurs predominantly into a single guided mode. We find that the fluorescence excitation line shape changes as the number of atoms is increased, eventually undergoing a splitting that provides evidence for the waveguide-mediated all-to-all interactions. Remarkably, in the regime of strong driving the light emitted into the waveguide is non-classical, with a significant negativity of the associated Wigner function. We show that both the emission properties and the non-Gaussian character of the light are robust against voids in the atom chain, enabling the experimental study of these effects with present-day technology. Our results offer a route towards novel types of fiber-coupled quantum light sources and an interesting perspective for probing the physics of interacting atomic ensembles through light.

Measurement-feedback control of chiral photon emission from an atom chain into a nanofiber

“…in Refs. [45,49,[56][57][58][59]. This method allows to access not only the average values but also the fluctuations and higher moments of time-integrated observables, such as the photon emission count and the time-integrated quadrature of the light emitted into the right-propagating mode.…”

“…When the output detected is a quadrature of the photocurrent via homodyne measurements, X α (t), the corresponding superoperator is [49,58]…”

“…photon emission takes place preferably into one of the modes travelling into a given direction. These features make the atom-nanofiber setting a promising candidate for the realization of photonic quantum technologies [38][39][40][41][42][43][44][45][46][47][48][49]. Here, we consider a scenario where a continuous measurement of the light emitted into one of the guided modes triggers the feedback.…”

Non-exponential decay of a collective excitation in an atomic ensemble coupled to a one-dimensional waveguide

“…Recently, the efficient coupling of atoms to nanophotonic structures in low dimensions [31] has enabled the study of almost perfectly one-dimensional systems that show infinite-range interactions [32] but also exotic chiral, coherent lightmatter interactions which depend on the polarisation of the incoming light [33]. Such wave guides have a high potential to generate non-classical states of light [34][35][36].…”