Quantum storage of heralded polarization qubits.
© Courtesy F. Bussières/University of Geneva
Quantum storage of heralded polarization qubits in birefringent and anisotropically absorbing materials.
Quantum computing and long-distance quantum communication will only be possible when a reliable source of quantum memory (a storage place for quantum information). The ideal quantum memory would store light with any polarization. Clausen et al. at Geneva University have achieved storage and retrieval of arbitrary polarization states of light from a solid-state quantum memory. A light source emitting single photons was used experimentally which were absorbed by a crystal containing rare-earth ions. Efficient storage of a photon’s polarization was achieved for ten to hundreds of nanoseconds by using a compensation technique. The team managed to retrieve the original state by reversing the procedure with a fidelity greater than the value obtained in classical memory. Thus, solid states of this kind are promising quantum memories for polarization qubits.