Superluminal two-color light in multiple Raman gain medium

TL;DR

This paper theoretically demonstrates how a specially configured Raman medium can produce a two-component light with superluminal group velocity, showing envelope advancement for the coupled component.

Contribution

It introduces a novel optical scheme using four Raman pump fields to generate superluminal two-color light with selective coupling to the medium.

Findings

Superluminal group velocity achieved for a specific light component.

Envelope advancement observed in the coupled probe field.

Selective coupling allows control over light propagation speed.

Abstract

We investigate theoretically the formation of two-component light with superluminal group velocity in a medium controlled by four Raman pump fields. In such an optical scheme only a particular combination of the probe fields is coupled to the matter and exhibits superluminal propagation, the orthogonal combination is uncoupled. The individual probe fields do not have a definite group velocity in the medium. Calculations demonstrate that this superluminal component experiences an envelope advancement in the medium with respect to the propagation in vacuum.