Suppression of the four-wave mixing amplification via Raman absorption

Abstract

We propose a method to controllably suppress the effect of the four-wave mixing caused by the coupling of the strong control optical field to both optical transitions in the $\mathrm{\Lambda }$ system under the conditions of electromagnetically induced transparency (EIT). At sufficiently high atomic density, this process leads to amplification of a weak optical signal field, that is detrimental for the fidelity of any EIT-based quantum information applications. Here we show that an additional absorption resonance centred around the Stokes field frequency, generated in such a four-wave mixing process, may efficiently suppress the unwanted probe amplification without affecting properties of the EIT interaction. We discuss the possibility of creating such tunable absorption using two-photon Raman absorption resonances in the other Rb isotope, and present some preliminary experimental results.

Keywords:

• Electromagnetically induced transparency
• four-wave mixing
• atomic coherence
• quantum memory
• Rb vapour

Acknowledgements

We thank Dr. David F. Phillips (CfA) for lending the Rubidium cell.

Notes

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by AFOSR [grant number FA9550-13-1-0098]. Dr. O’Brien would like to acknowledge support from NSERC (Canada).