Towards Cavity-Assisted Fast Rubidium-Tuned Quantum Light Sources

The realization of large-scale quantum networks has become a global priority at the frontier of quantum information science. As a technological backbone for these systems, the development of scalable single-photon sources tuned to rubidium transitions is of paramount importance. We report on our progress regarding the implementation of a DLCZ protocol heralded single-photon source [1] using an ensemble of cold rubidium simultaneously coupled to two optical cavities at the Stony Brook University (SBU) QIT Laboratory. Using a lambda system in the D1/D2 line, we stabilize one cavity to the F=1 to F’=1 transition. After pumping the atoms with the F=2 to F’=1 ('write') field, we observe Stokes photons emitted into the cavity mode with a rate of several kHz. We show preliminary results where these photons are used to herald the generation of Anti-Stokes photons (using a F=1 to F’=1 'read' field) into a second cavity mode coupled to the F=2 to F’=1 transition, achieving a cavity-assisted DLCZ landscape. We are planning to combine this source with a single-photon free-space optical link between SBU and Brookhaven National Laboratory (BNL) over a line-of-sight distance of 20km. We will also report on the current progress towards transmitting these rubidium-tuned photons from SBU and storing them in a remotely located atomic quantum memory at the BNL site.

[1] L.M. Duan, et. al., Nature, 414, 6862 (2001).