Toward bi-chromatic intensity squeezing at telecom wavelength using FWM (Four Wave Mixing) in Rb vapor

Entangled photon pairs and fields are essential for various optical quantum information processing processes, and particularly for quantum teleportation protocols. Distributing entanglement over long distances requires transmitted photons to fall within telecom wavelength bands, and their counterpart to be strongly coupled with local quantum nodes. In this research, we investigate the possibility to generate quantum correlated optical fields satisfying the above-mentioned requirements through the four-wave mixing (FWM) process in hot Rubidium vapor. Using a 4-level double-ladder system in which two strong pump fields drive the system up to 6S1/2 state of Rb85, we observe amplification of a weak seed field at 795nm, as well as the generation of the new field at 1324nm via the FWM gain. We can reach over 10% conversion rate with respect to the weak seed, providing promising conditions for observation of the quantum correlations between these two fields. The high conversion rate is ideal for quantum information applications relying on continuous variable (CV) entangled states.