Quantum control of dispersion in electromagnetically induced transparency via interacting dressed ground states

TL;DR

This paper explores how to manipulate light dispersion in electromagnetically induced transparency by using dressed ground states in a five-level atomic system, enabling precise control over light speed and resonance features.

Contribution

It introduces a novel five-level system with RF/microwave fields creating dressed states that modify EIT properties and dispersion control.

Findings

Discovery of narrow resonances inside the EIT window.

Control of resonance position and width via RF/microwave fields.

Enhanced manipulation of probe light dispersion and group velocity.

Abstract

We offer a general treatment of electromagnetically induced transparency (EIT) in a five level system consisting of four metastable ground states. Two additional RF/microwave fields coherently couple the two ground states of the standard EIT $\Lambda$ atom to a pair of additional hyperfine states in the ground state manifold, generating two sets of dressed states that interact via the probe and control lasers, which couple to the electronic excited state. These new hyperfine dressed states manifest themselves in the linear optical susceptibility of the probe as new resonances in addition to the Autler-Townes doublet characteristic of EIT. In particular, we show that the existence of two new narrow resonances, whose width are limited only by ground state decoherence, appear inside the normal EIT transparency window. We show that by controlling the intensity of these RF/microwave fields, one can engineer both the position and width of these narrow resonances and thereby exercise additional control over both the dispersion and group velocity of the probe.