Light storage in an optically thick atomic ensemble under conditions of electromagnetically induced transparency and four-wave mixing

TL;DR

This paper investigates how four-wave mixing affects light storage in hot Rb atomic ensembles under EIT conditions, revealing that information in a seeded Stokes field is not independently preserved during storage.

Contribution

It provides a combined theoretical and experimental analysis of FWM's impact on EIT-based light storage, highlighting limitations in preserving certain encoded information.

Findings

FWM modifies signal pulse propagation during EIT storage.

Seeded Stokes field information is not independently stored.

A simple model describes FWM's impact on spin wave dynamics.

Abstract

We study the modification of a traditional electromagnetically induced transparency (EIT) stored light technique that includes both EIT and four-wave mixing (FWM) in an ensemble of hot Rb atoms. The standard treatment of light storage involves the coherent and reversible mapping of one photonic mode onto a collective spin coherence. It has been shown that unwanted, competing processes such as four-wave mixing are enhanced by EIT and can significantly modify the signal optical pulse propagation. We present theoretical and experimental evidence to indicate that while a Stokes field is indeed detected upon retrieval of the signal field, any information originally encoded in a seeded Stokes field is not independently preserved during the storage process. We present a simple model that describes the propagation dynamics of the fields and the impact of FWM on the spin wave.