Controllable steep dispersion with gain in a four-level N-scheme with four-wave mixing

TL;DR

This paper theoretically investigates how four-wave mixing in a four-level atomic N-scheme can control light pulse speed and amplification, enabling tunable superluminal or slow light propagation.

Contribution

It introduces a method to control light group velocity and gain using four-wave mixing in a four-level atomic system, expanding understanding of light-matter interactions.

Findings

Four-wave mixing significantly affects signal group velocity and absorption.

Propagation can be tuned from superluminal to slow light regimes.

The system allows for amplification of the signal field.

Abstract

We present a theoretical analysis of the propagation of light pulses through a medium of four-level atoms, with two strong pump fields and a weak signal field in an N-scheme arrangement. We show that the generation of four-wave mixing has a profound effect on the signal field group velocity and absorption, allowing the signal field propagation to be tuned from superluminal to slow light regimes with amplification.