High reflection emission assisted by phase compensation via anomalous dispersion

TL;DR

This paper demonstrates that anomalous dispersion-induced phase compensation can significantly enhance reflection in a three-level atomic system, with maximum reflection achieved near two-photon resonance conditions.

Contribution

It provides both experimental and theoretical evidence that phase compensation via anomalous dispersion boosts reflection efficiency in atomic four-wave mixing.

Findings

Maximum reflection occurs off-resonance of atomic transitions.

Enhanced reflection is due to phase compensation from anomalous dispersion.

Reflection efficiency peaks near two-photon resonance detuning.

Abstract

The reflection spectrum of a probe light in a -type three-level atomic system coupled by an off-resonant standing-wave is investigated experimentally and theoretically. We show that the maximum value of reflection coefficient occurs when both of the coupling and probe lights are tuned off resonances from the atomic transitions. The nature of enhanced reflection is attributed to the phase compensation caused by the anomalous dispersion, which leads to a significant reduction of nonlinear phase mismatch in atomic four-wave mixing. At certain detuning of coupling and probe frequencies near two-photon resonance, there exits a best compensation, so the reflection efficiency reaches its maximum. The dependences of efficiency on the intensity of coupling fields and the density of atoms are also studied.