Microwave dressing of Rydberg dark states

TL;DR

This paper investigates how microwave fields can control Rydberg EIT in cold rubidium gases, enabling tunable light propagation and revealing enhanced interactions and many-body effects.

Contribution

It demonstrates microwave-induced Autler-Townes splitting in Rydberg EIT and shows how microwave dressing enhances interactions and causes many-body phenomena.

Findings

Microwave coupling causes Autler-Townes splitting of EIT resonance.

Microwave dressing allows tuning of the group index by ±10^5.

Evidence of a 1/R^3 energy shift indicating many-body interaction effects.

Abstract

We study electromagnetically induced transparency (EIT) in the 5s$\rightarrow$5p$\rightarrow$46s ladder system of a cold $^{87}$Rb gas. We show that the resonant microwave coupling between the 46s and 45p states leads to an Autler-Townes splitting of the EIT resonance. This splitting can be employed to vary the group index by $\pm 10^5$ allowing independent control of the propagation of dark state polaritons. We also demonstrate that microwave dressing leads to enhanced interaction effects. In particular, we present evidence for a $1/R^3$ energy shift between Rydberg states resonantly coupled by the microwave field and the ensuing breakdown of the pair-wise interaction approximation.