We study optical gain in a gas of cold K39 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.
|Number of pages
|Physical Review A - Atomic, Molecular, and Optical Physics
|Published - 9 Sept 2019