Progress Towards Hyperentangled Photon Pair Generation Using Laser-Cooled Atoms

We present progress towards the generation of hyperentangled photon pairs in a cold atomic ensemble with an off-resonant pump. Relevant prior work[1,2] in cold trapped atoms has exploited an EIT-based lambda level schemes with an off-resonant write beam and a near-resonant read beam. Our proposed implementation uses a single pump field that is detuned by roughly half the ground state hyperfine splitting for both the read and the write process. This scheme is designed to produce photons entangled in both polarization and frequency, with the emitted frequencies differing by the rubidium ground-state hyperfine splitting. The experiment is carried out in a 3D magneto-optical trap of rubidium-87 atoms. We present the details of our level scheme, experimental setup, and progress towards the end goal of hyperentangled photon pairs generation. We additionally present studies of the dependence of correlated photon pair generation on pump beam spatial profile and pump detuning.

[1] Hui Yan, Shanchao Zhang, J. F. Chen, M. M. T. Loy, G. K. L. Wong, and Shengwang Du Phys. Rev. Lett. 106, 033601 (2011)

[2] Tian-Ming Zhao, Yong Sup Ihn, and Yoon-Ho Kim Phys. Rev. Lett. 122, 123607 (2019).