Quantum Storage in Solid State Atomic Ensembles

Hugues de Riedmatten, Mikael Afzelius

Hugues de Riedmatten, Christoph Simon, Sara R. Hastings-Simon +6 more

Atomic ensembles in the solid state using rare-earth ion doped materials can be used to implement a quantum memory for the storage of multiple temporal modes. First experimental steps will be presented.

Joshua Nunn

Rikizo Ikuta, Toshiki Kobayashi, Tetsuo Kawakami +8 more

Long-lifetime quantum storages accessible to the telecom photonic infrastructure are essential to long-distance quantum communication. Atomic quantum storages have achieved subsecond storage time corresponding to 1000 km transmission time for a telecom photon through a quantum repeater algorithm. However, the telecom photon cannot be directly interfaced to typical atomic storages. Solid-state quantum frequency conversions fill this wavelength gap. Here we report on the experimental demonstration of a polarization-insensitive solid-state quantum frequency conversion to a telecom photon from a short-wavelength photon entangled with an atomic ensemble. Atom-photon entanglement has been generated with a Rb atomic ensemble and the photon has been translated to telecom range while retaining the entanglement by our nonlinear-crystal-based frequency converter in a Sagnac interferometer.

Matthew J. Sellars

M. U. Staudt, Mikael Afzelius, Hugues de Riedmatten +6 more

High-visibility interference of photon echoes generated in spatially separated solid-state atomic ensembles is demonstrated. The solid-state ensembles were LiNbO(3) waveguides doped with erbium ions absorbing at 1.53 microm. Bright coherent states of light in several temporal modes (up to 3) are stored and retrieved from the optical memories using two-pulse photon echoes. The stored and retrieved optical pulses, when combined at a beam splitter, show almost perfect interference, which demonstrates both phase preserving storage and indistinguishability of photon echoes from separate optical memories. By measuring interference fringes for different storage times, we also show explicitly that the visibility is not limited by atomic decoherence. These results are relevant for novel quantum-repeater architectures with photon-echo based multimode quantum memories.