Enhancement of optically pumped spin orientation via spin-exchange collisions at low vapor density

• Published in: Physical review. A, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2012-04, Vol.85 (4), Article 043402
• Main Authors: Chalupczak, W., Godun, R. M., Anielski, P., Wojciechowski, A., Pustelny, S., Gawlik, W.
• Format: Article
• Language: English
• Subjects: Atomic properties; Collisions; Density; Mathematical models; Optical pumping; Orientation; Populations; Zeeman effect
• ISSN: 1050-2947; 1094-1622
• DOI: 10.1103/PhysRevA.85.043402

An effect is demonstrated where off-resonant optical pumping is enhanced by spin-exchange collisions, which enables a high degree of spin orientation to be obtained in alkali-metal atoms. The experiment with room-temperature cesium vapor employs radio-frequency spectroscopy under conditions of the nonlinear Zeeman effect that allow the populations of the individual Zeeman sublevels to be determined. The improved efficiency of atomic orientation leads to a significant reduction of population relaxation out of the state with maximum magnetic quantum number m (stretched state), which is observed as a narrowing of radio-frequency resonances. Spin-exchange collisions play a crucial role in this effect although the applied atomic density similar to 10 super(11) cm super(3) corresponds to collision rates not greater than several tens of Hz. A simplified theoretical model has been developed to reproduce the measurement results numerically.