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Quantum nonlinear optics with single photons enabled by strongly interacting atoms

2012; Nature Portfolio; Volume: 488; Issue: 7409 Linguagem: Inglês

10.1038/nature11361

1476-4687

Thibault Peyronel, Ofer Firstenberg, Qiyu Liang, Sebastian Hofferberth, Alexey V. Gorshkov, Thomas Pohl, Mikhail D. Lukin, Vladan Vuletić,

Quantum Information and Cryptography

A cold, dense atomic gas is found to be optically nonlinear at the level of individual quanta, thereby opening possibilities for quantum-by-quantum control of light fields, including single-photon switching and deterministic quantum logic. In conventional optical materials, nonlinear interactions between single photons are negligibly weak. This paper demonstrates that a cold, dense atomic gas can be nonlinear at the level of individual quanta, exhibiting strong absorption of photon pairs, while remaining transparent to single photons. The approach opens up possibilities for quantum-by-quantum control of light fields, including single-photon switching and deterministic quantum logic. The authors suggest that it could also be extended to other material systems with strong interactions between their constituents that can be coupled to light. The realization of strong nonlinear interactions between individual light quanta (photons) is a long-standing goal in optical science and engineering1,2, being of both fundamental and technological significance. In conventional optical materials, the nonlinearity at light powers corresponding to single photons is negligibly weak. Here we demonstrate a medium that is nonlinear at the level of individual quanta, exhibiting strong absorption of photon pairs while remaining transparent to single photons. The quantum nonlinearity is obtained by coherently coupling slowly propagating photons3,4,5 to strongly interacting atomic Rydberg states6,7,8,9,10,11,12 in a cold, dense atomic gas13,14. Our approach paves the way for quantum-by-quantum control of light fields, including single-photon switching15, all-optical deterministic quantum logic16 and the realization of strongly correlated many-body states of light17.