Amazing stuff! However, through Google search I found what appears to be a similar work published in 2015 (a PhD dissertation).
"Photons are robust and can travel long distances, making them ideal carriers of quantum information. However, communication between nodes on a network requires directional control of the photons. Emission from excited atoms, for instance, can generally take any direction.
Li et al. demonstrated a direction-switchable single-photon emitter using Rydberg polaritons. The ensemble of cesium atoms is first excited with a laser pulse, and then a second retrieval pulse is used to de-excite the system and extract the stored photon. The direction of the retrieval laser determines the direction of the emitted photon. Using this protocol, the angle difference between the incoming and redirected photon can be up to 100°. Such control over the directional emission should prove useful for quantum communication."
From the abstract:
"A promising route toward quantum networking is via photons as information carriers, requiring deterministic quantum nonlinear optical operations and single-photon routing.
Here, we demonstrate a direction-switchable single-photon emitter using a Rydberg polariton. The Rydberg component of the stored photon is changed using a stimulated Raman transition with a specific intermediate state.
By adjusting the direction of the retrieval laser, we can redirect the emitted photon into a rich variety of alternative modes. We experimentally demonstrate a redirection angle of .
Building upon this scheme, we propose a quantum routing of single photons with output channels by rotation of the retrieval laser, where all directions have identical routing efficiency. In addition, the protocol reduces the effect of motional dephasing, increasing the photon lifetime to µs ( times the photon processing time), enabling functional quantum devices based on Rydberg polaritons."
Fig. 1. Experimental realization and relevant energy levels.
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