High speed spatially multimode atomic memory

TL;DR

This paper investigates a high-speed, multimode atomic quantum memory capable of storing and retrieving short light pulses, optimizing process parameters, and estimating its capacity for multiple transverse modes as a quantum hologram.

Contribution

It provides an analytical framework for optimizing multimode atomic memory processes and evaluates its capacity for storing multiple transverse modes.

Findings

Optimized writing and reading processes for atomic memory.

Analytical solutions for field and atomic coherence evolution.

Estimated multimode storage capacity as a quantum hologram.

Abstract

We study the coherent storage and retrieval of a very short multimode light pulse in an atomic ensemble. We consider a quantum memory process based on the conversion of a signal pulse into a long-lived spin coherence via light matter interaction in an on-resonant Lambda-type system. In order to study the writing and reading processes we analytically solve the partial differential equations describing the evolution of the field and of the atomic coherence in time as well as in space. We show how to optimize the process for writing as well as for reading. If the medium length is fixed, for each length, there is an optimal value of the pulse duration. We discuss the information capacity of this memory scheme and we estimate the number of transverse modes that can be stored as a quantum hologram.