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

摘要

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