Suppression of the four-wave mixing amplification via Raman absorption

TL;DR

This paper introduces a method to suppress unwanted four-wave mixing amplification in EIT systems using Raman absorption, enhancing quantum information fidelity.

Contribution

It demonstrates a controllable suppression technique for four-wave mixing in EIT via Raman absorption resonances, supported by preliminary experimental results.

Findings

Raman absorption can effectively suppress four-wave mixing amplification.

The method preserves EIT properties while reducing signal distortion.

Preliminary experiments show promising results for tunable suppression.

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 $\Lambda$ system under the conditions of electromagnetically induced transparency. 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 centered around the idler field frequency, generated in such a four-wave mixing process, may efficiently suppress the unwanted signal 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.