The choice of a V-type system with the probe field in the subluminal or superluminal regimen

TL;DR

This paper investigates how the angle between dipole moments in V-type systems affects the probe field's group velocity, enabling control over subluminal or superluminal light propagation through system geometry.

Contribution

It demonstrates that the group velocity in V-type systems can be tuned between subluminal and superluminal regimes by adjusting the dipole moment angle and system configuration.

Findings

Group velocity alternates between subluminal and superluminal regimes.

Proper geometry allows control of light propagation speed.

The system's behavior depends on dipole moment orientation.

Abstract

We study the influence of the angle between the two dipole transition moments on the group velocity for two kinds of three-level V-type systems with spontaneously generated coherence and incoherent pumping. The group velocity of the probe field for both kinds of the V-type systems alternates between the subluminal or superluminal regimen. We can choose a real three-level V-type system from atoms or molecules to exhibit subluminal or superluminal light propagation by a proper geometry of the probe, coupling and incoherent pumping fields, which depends on the angle between the two dipole transition moments.