Using the process of cavity-enhanced spontaneous parametric down-conversion (SPDC), we generate a narrow-band polarization-entangled photon pair resonant on the rubidium (Rb) D1 line (795 nm). The degenerate single-mode photon pair is selected by multiple temperature controlled etalons. The linewidth of generated polarization-entangled photon pairs is 15 MHz which matches the typical atomic memory bandwidth. The measured Bell parameter for the polarization-entangled photons S=2.73+-0.04 which violates the Bell-CHSH inequality by ~18 standard deviations. The presented entangled photon pair source could be utilized in quantum communication and quantum computing based on quantum memories in atomic ensemble.
@article{arxiv.1607.04151,
title = {Generation of narrow-band polarization-entangled photon pairs at a rubidium D1 line},
author = {Long Tian and Shu-Jing Li and Hao-Xiang Yuan and Hai Wang},
journal= {arXiv preprint arXiv:1607.04151},
year = {2016}
}