Abstract-Two-way conversion of microwave and terahertz radiation into optical fields in Rydberg gases

Martin Kiffner, Amir Feizpour, Krzysztof T. Kaczmarek, Dieter Jaksch, Joshua Nunn

(Submitted on 26 Jan 2016 (v1), last revised 26 May 2016 (this version, v2))

http://arxiv.org/abs/1601.07100

We show that cold Rydberg gases enable an efficient six-wave mixing process where microwave or terahertz fields are coherently converted into optical fields and vice versa. This process is made possible by the long lifetime of Rydberg states, the strong coupling of millimeter waves to Rydberg transitions and a quantum interference effect related to Electromagnetically Induced Transparency. We show that conversion efficiencies within an independent atom approach are of the order of 95% and analyse the impact of dipole-dipole interactions on our scheme. We find that effective conversion efficiencies in the presence of Rydberg-Rydberg interactions can still be as high as 85% based on an implementation with Rubidium atoms. Our frequency conversion scheme does not require cavities and can be implemented for a broad spectrum of terahertz and microwave fields due to the abundance of transitions within the Rydberg manifold.