Multipass configuration for improved squeezed vacuum generation in hot Rb vapor
M. Zhang, Melissa A. Guidry, R. Nicholas Lanning +4 more
We study a squeezed vacuum field generated in hot Rb vapor via the polarization self-rotation effect. Our previous experiments showed that the amount of observed squeezing may be limited by the contamination of the squeezed vacuum output with higher-order spatial modes, also generated inside the cell. Here, we demonstrate that the squeezing can be improved by making the light interact several times with a less dense atomic ensemble. With optimization of some parameters we can achieve up to $\ensuremath{-}2.6$ dB of squeezing in the multipass case, which is a 0.6 dB improvement compared to the single-pass experimental configuration. Our results show that, other than the optical depth of the medium, the spatial mode structure and the cell configuration also affect the squeezing level.
arXiv:1705.02914•Physical Review A•Jul 19, 2017•13 citations