In-situ Raman gain between hyperfine ground states in a potassium magneto-optical trap

Abstract

We study optical gain in a gas of cold 39K atoms. The gain is observed during operation of a conventional magneto-optical trap without the need for additional fields. Measurements of transmission spectra from a weak probe show that the gain is due to stimulated Raman scattering between hyperfine ground states. The experimental results are reproduced by a simplified six-level model, which also helps explain why such gain is not observed in similar experiments with rubidium or cesium.

7 pages, 7 figures; submitted for publication; v2: minor changes in response to Referee comments; v3: version accepted for publication in PRA