Spin Wave Storage using Chirped Control Fields in Atomic Frequency Comb based Quantum Memory

TL;DR

This paper analyzes spin wave storage in atomic frequency comb quantum memories using chirped control fields, demonstrating reduced control field intensities but a trade-off in multimode capacity.

Contribution

It provides a detailed analysis of chirped adiabatic control fields for spin wave storage, highlighting their efficiency and impact on multimode capacity.

Findings

Chirped control fields require weaker intensities than $\pi$-pulses.

Chirped fields reduce multimode storage capacity.

The analysis is based on realistic parameters for rare-earth-ion-doped solids.

Abstract

It has been shown that an inhomogeneously broadened optical transition shaped into an atomic frequency comb can store a large number of temporal modes of the electromagnetic field at the single photon level without the need to increase the optical depth of the storage material. The readout of light modes is made efficient thanks to the rephasing of the optical-wavelength coherence similarly to photon echo-type techniques and the re-emission time is given by the comb structure. For on-demand readout and long storage times, two control fields are used to transfer back and forth the optical coherence into a spin wave. Here, we present a detailed analysis of the spin wave storage based on chirped adiabatic control fields. In particular, we verify that chirped fields require significantly weaker intensities than $\pi$-pulses. The price to pay is a reduction of the multimode storage capacity that we quantify for realistic material parameters associated with solids doped with rare-earth-metal ions.