Controlling Irreversibility and Directional Flow of Light with Atomic Motion

TL;DR

This paper demonstrates how atomic motion influences light irreversibility and directionality in EIT, enabling control over light flow and potential applications in quantum velocimetry.

Contribution

It introduces a method to control light directionality using atomic motion in EIT and reveals new insights into dispersive phase effects.

Findings

Atomic motion induces light irreversibility and directional control.

Interference patterns can determine atomic velocity.

Dispersive phase sign affects interference features.

Abstract

The Doppler effect of moving atoms can create irreversibility of light. We show that the laser field in electromagnetic induced transparency (EIT) scheme with atomic motion can control the directional propagation of two counter-propagating probe fields in atomic gas cell. The quantum coherence effect serves as an optical transistor. Interference of the two output fields from the cell shows useful feature for determining the mean atomic velocity and can be useful as quantum velocimeter. We also find that the sign of the dispersive phase in EIT has a unique property, which helps to explain certain features in the interference.