Group of Applied Physics, University of Geneva, Geneva 1211, Switzerland.
Nat Commun. 2013;4:2324. doi: 10.1038/ncomms3324.
The parametric interaction of light beams in nonlinear materials is usually thought to be too weak to be observed when the fields involved are at the single-photon level. However, such single-photon level nonlinearity is not only fundamentally fascinating but holds great potential for emerging technologies and applications involving heralding entanglement at a distance. Here we use a high-efficiency waveguide to demonstrate the sum-frequency generation between a single photon and a single-photon level coherent state. The use of an integrated, solid state, room temperature device and telecom wavelengths makes this type of system directly applicable to future quantum communication technologies such as device-independent quantum key distribution.
光束在非线性材料中的参数相互作用通常被认为太弱，以至于在涉及的场处于单光子水平时无法观察到。然而，这种单光子水平的非线性不仅在基础研究中非常有趣，而且在新兴技术和应用中具有很大的潜力，例如远距离纠缠的预示。在这里，我们使用高效波导演示了单光子和单光子相干态之间的和频产生。采用集成的固态室温器件和电信波长使得这种类型的系统可以直接应用于未来的量子通信技术，如设备无关的量子密钥分发。
