Dynamics of slow light and light storage in a Doppler-broadened electromagnetically-induced-transparency medium: A numerical approach

TL;DR

This paper introduces a numerical method to analyze slow light and light storage in a Doppler-broadened EIT medium at finite temperatures, accounting for atomic motion and coherence decay.

Contribution

It develops a coupled Schrödinger equation framework incorporating atomic motion for simulating EIT dynamics at finite temperatures.

Findings

Numerical results agree well with experimental data for slow light and storage.

The scheme effectively models ground-state coherence decay at finite temperatures.

The method can estimate the temperature of the EIT medium.

Abstract

We present a numerical scheme to study the dynamics of slow light and light storage in an electromagneticallyinduced- transparency (EIT) medium at finite temperatures. Allowing for the motional coupling, we derive a set of coupled Schr\"{o}dinger equations describing a boosted closed three-level EIT system according to the principle of Galilean relativity. The dynamics of a uniformly moving EIT medium can thus be determined by numerically integrating the coupled Schr\"odinger equations for atoms plus one ancillary Maxwell-Schr\"odinger equation for the probe pulse. The central idea of this work rests on the assumption that the loss of ground-state coherence at finite temperatures can be ascribed to the incoherent superposition of density matrices representing the EIT systems with various velocities. Close agreements are demonstrated in comparing the numerical results with the experimental data for both slow light and light storage. In particular, the distinct characters featuring the decay of ground-state coherence can be well verified for slow light and light storage. This warrants that the current scheme can be applied to determine the decaying profile of the ground-state coherence as well as the temperature of the EIT medium.