Cohen Offir, Lundeen Jeff S, Smith Brian J, Puentes Graciana, Mosley Peter J, Walmsley Ian A
Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK.
Phys Rev Lett. 2009 Mar 27;102(12):123603. doi: 10.1103/PhysRevLett.102.123603.
We experimentally control the spectral structure of photon pairs created via spontaneous four-wave mixing in microstructured fibers. By fabricating fibers with designed dispersion, one can manipulate the photons' wavelengths, joint spectrum, and, thus, entanglement. As an example, we produce photon pairs with no spectral correlations, allowing direct heralding of single photons in pure-state wave packets without filtering. We achieve an experimental purity of (85.9+/-1.6)%, while theoretical analysis and preliminary tests suggest that 94.5% purity is possible with a much longer fiber.
我们通过实验控制了在微结构光纤中通过自发四波混频产生的光子对的光谱结构。通过制造具有设计色散的光纤，可以操纵光子的波长、联合光谱，进而操纵纠缠。例如，我们产生了没有光谱相关性的光子对，无需滤波就能直接在纯态波包中预示单光子。我们实现了(85.9±1.6)%的实验纯度，而理论分析和初步测试表明，使用长得多的光纤有可能达到94.5%的纯度。
