Group of Applied Physics, University of Geneva, CH-1211 Geneva 4, Switzerland.
Nat Commun. 2010 Apr 12;1:12. doi: 10.1038/ncomms1010.
The future challenge of quantum communication is scalable quantum networks, which require coherent and reversible mapping of photonic qubits onto atomic systems (quantum memories). A crucial requirement for realistic networks is the ability to efficiently store multiple qubits in one quantum memory. In this study, we show a coherent and reversible mapping of 64 optical modes at the single-photon level in the time domain onto one solid-state ensemble of rare-earth ions. Our light-matter interface is based on a high-bandwidth (100 MHz) atomic frequency comb, with a predetermined storage time of ≳ 1 μs. We can then encode many qubits in short (<10 ns) temporal modes (time-bin qubits). We show the good coherence of mapping by simultaneously storing and analysing multiple time-bin qubits.
量子通信的未来挑战是可扩展的量子网络，这需要将光子量子比特相干且可逆地映射到原子系统（量子存储器）上。对于实际网络来说，一个关键的要求是能够有效地在一个量子存储器中存储多个量子比特。在这项研究中，我们在时域中实现了 64 个光模式在单光子水平上的相干且可逆的映射，将其映射到一个固态稀土离子系综上。我们的光物质接口基于一个高带宽（100 MHz）原子频梳，具有 ≳ 1 μs 的预定存储时间。然后，我们可以在短时间内（<10 ns）编码许多量子比特（时间-bin 量子比特）。我们通过同时存储和分析多个时间-bin 量子比特来展示映射的良好相干性。
