In-situ dual-port polarization contrast imaging of Faraday rotation in a high optical depth ultracold 87Rb atomic ensemble
Niels-Bohr-Institute, Danish Quantum Optics Center QUANTOP, Copenhagen
2 Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
Received in final form: 8 June 2012
Published online: 4 September 2012
We study the effects of high optical depth and density on the performance of a light-atom quantum interface. An in-situ imaging method, a dual-port polarization contrast technique, is presented. This technique is able to compensate for image distortions due to refraction. We propose our imaging method as a tool to characterize atomic ensembles for high capacity spatial multimode quantum memories. Ultracold dense inhomogeneous rubidium samples are imaged and we find a resonant optical depth as high as 680 on the D1 line. The measurements are compared with light-atom interaction models based on Maxwell-Bloch equations. We find that an independent atom assumption is insufficient to explain our data and present corrections due to resonant dipole-dipole interactions.
Key words: Topical issue: High Dimensional Quantum Entanglement. Guest editors: Sonja Franke-Arnold, Alessandra Gatti and Nicolas Treps
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012