Rydberg-induced optical nonlinearities from a cold atomic ensemble trapped inside a cavity

TL;DR

This paper experimentally investigates the optical nonlinearities in a cold atomic ensemble inside a cavity, excited to Rydberg states, revealing state-dependent behaviors and modeling them with a Rydberg bubble approach.

Contribution

It provides the first detailed experimental characterization of Rydberg-induced nonlinearities in a cavity-trapped cold atomic ensemble, including a new dynamical decay model for D states.

Findings

Nonlinearities explained by van der Waals interactions for S states

D states require a dynamical decay into a dark state for accurate modeling

Measured nonlinearities align with a Rydberg bubble model incorporating decay

Abstract

We experimentally characterize the optical nonlinear response of a cold atomic medium placed inside an optical cavity, and excited to Rydberg states. The excitation to S and D Rydberg levels is carried out via a two-photon transition in an EIT (electromagnetically induced transparency) configuration, with a weak (red) probe beam on the lower transition, and a strong (blue) coupling beam on the upper transition. The observed optical nonlinearities induced by S states for the probe beam can be explained using a semi-classical model with van der Waals' interactions. For the D states, it appears necessary to take into account a dynamical decay of Rydberg excitations into a long-lived dark state. We show that the measured nonlinearities can be explained by using a Rydberg bubble model with a dynamical decay.