Generation and delayed retrieval of spatially multimode Raman scattering in warm rubidium vapors

TL;DR

This paper demonstrates the creation, storage, and retrieval of spatially multimode light in warm rubidium vapors using collective Raman scattering, enabling delayed correlated image pairs with potential quantum information applications.

Contribution

It introduces a method for storing and retrieving multiple spatial modes in warm atomic vapors via Raman scattering and spin wave conversion, with analysis of spatial effects and decoherence.

Findings

Storage of spatial modes up to microseconds achieved

Quantified number of modes via intensity fluctuation correlations

Decoherence effects studied with different buffer gases

Abstract

We apply collective Raman scattering to create, store and retrieve spatially multimode light in warm rubidium-87 vapors. The light is created in a spontaneous Stokes scattering process. This is accompanied by the creation of counterpart collective excitations in the atomic ensemble -- the spin waves. After a certain storage time we coherently convert the spin waves into the light in deterministic anti-Stokes scattering. The whole process can be regarded as a delayed four-wave mixing which produces pairs of correlated, delayed random images. Storage of higher order spatial modes up to microseconds is possible owing to usage of a buffer gas. We study the performance of the Raman scattering, storage and retrieval of collective excitations focusing on spatial effects and the influence of decoherence caused by diffusion of rubidium atoms in different buffer gases. We quantify the number of modes created and retrieved by analyzing statistical correlations of intensity fluctuations between portions of the light scattered in the far field.