Nanofibre and cold atoms: a new quantum platform

The integration of cold atoms with nanoscopic waveguides has sparked considerable interest in recent years, giving rise to a rapidly expanding field of research: quantum electrodynamics in waveguides. Such platforms should allow easier integration and better performance than free space devices, ultimately leading to chip-based technologies for a future quantum internet.

In addition, the marriage between cold atoms and nanophotonics opens new directions for the exploration of atom-photon interactions. By modifying the structure of the waveguide, it is possible to increase the interaction between light and atoms in a single passage, or to achieve interactions of tunable range between the atoms.

However, so far, experimental progress has been very limited due to the difficulty of marrying these two worlds. Using a few thousand cold atoms, trapped near an optical fibre, LKB researchers created for the first time an entangled atomic state that can subsequently be stored and read as a single guided photon.


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Using 1D networks of cesium atoms around a nanofiber, researchers at the Kastler Brossel Laboratory realized an entangled state of several thousand atoms and succeeded in reading this quantum superposition as a single guided photon. LKB (CNRS/Sorbonne University/ENS Paris/Collège de France))


Image of an optical nanofiber (in red) inside a vacuum chamber. Cold atoms are trapped around the fibre, about 200 nanometers from the surface, and interfaced via guided light. These “fibrous atoms” constitute an integrated platform for quantum information networks and a new field of investigation for quantum electrodynamics in waveguide. © N. V. Corzo, LKB (CNRS/Sorbonne University/ENS Paris/Collège de France)