Tuning the phase sensitivity of a double-lambda system with a static magnetic field

TL;DR

This paper investigates how a static magnetic field influences the phase sensitivity of a double-lambda atomic system, enabling control over optical properties and switching between slow and fast light, with potential applications in quantum and nonlinear optics.

Contribution

It demonstrates a novel method to tune phase sensitivity in a double-lambda system using a magnetic field, transforming phase-insensitive processes into phase-sensitive ones.

Findings

Magnetic field controls gain and refractive index of probe.

Turning magnetic field on makes the system phase-sensitive.

Switching between slow and fast light observed with magnetic or phase adjustments.

Abstract

We study the effect of a DC magnetic field on the phase sensitivity of a double-lambda system coupled by two laser fields, a probe and a pump. It is demonstrated that the gain and the refractive index of the probe can be controlled by either the magnetic field or the relative phase between the two laser fields. More interestingly, when the system reduces to a single-lambda system, turning on the magnetic field transforms the system from a phase-insensitive process to a phase-sensitive one. In the pulsed-probe regime, we observed switching between slow and fast light when the magnetic field or the relative phase was adjusted. Experiments using a coated 87Rb vapor cell produced results in good agreement with our numerical simulation. This work provides a novel and simple means to manipulate phase sensitive electromagnetically-induced-transparency or four-wave mixing, and could be useful for applications in quantum optics, nonlinear optics and magnetometery based on such systems.