Continuous-wave quantum light control via engineered Rydberg-induced dephasing

TL;DR

This paper investigates continuous-wave all-optical single-photon transistors using Rydberg atom ensembles, highlighting how collective interactions induce dephasing mechanisms that enhance device efficiency and control in quantum light manipulation.

Contribution

It introduces new mechanisms of probe-induced dephasing in Rydberg-based SPTs, extending their operational understanding and potential applications in quantum photonics.

Findings

Two distinct dephasing mechanisms identified that improve device efficiency.

Numerical simulations demonstrate high control-photon absorption probabilities.

Device configurations in free space and cavities show comparable performance.

Abstract

We analyze several implementations of all-optical single-photon transistors (SPTs) operating in the continuous-wave (cw) regime, as presented in the companion paper [Phys. Rev. A 113, L011701 (2026)]. The devices rely on ensembles of Rydberg atoms interacting via van der Waals interactions. Under electromagnetically induced transparency (EIT), a weak probe field is fully transmitted through the atomic ensemble in the absence of control photons. Exciting a collective Rydberg state with a single control photon breaks the EIT condition, thereby strongly suppressing the probe transmission. We show how collective Rydberg interactions in an atomic ensemble, confined either in an optical cavity or in free space, give rise to two distinct probe-induced dephasing mechanisms. These processes localize the control excitations, extend their lifetimes, and increase the device efficiency. We characterize the SPTs in terms of control-photon absorption probability and probe gain, supported by numerical simulations of realistic one- and three-dimensional ensembles. The proposed cw devices complement previously demonstrated SPTs and broaden the toolbox of quantum light manipulation circuitry.