We report free-space distribution of entangled photon pairs over a noisy ground atmosphere of 13 km. It is shown that the desired entanglement can still survive after both entangled photons have passed through the noisy ground atmosphere with a distance beyond the effective thickness of the aerosphere. This is confirmed by observing a spacelike separated violation of Bell inequality of 2.45 ± 0.09. On this basis, we exploit the distributed entangled photon source to demonstrate the Bennett-Brassard 1984 quantum cryptography scheme. The distribution distance of entangled photon pairs achieved in the experiment is for the first time well beyond the effective thickness of the aerosphere, hence presenting a significant step towards satellite-based global quantum communication. © 2005 The American Physical Society.
Peng Cheng-Zhi;Yang Tao;Bao Xiao-Hui;Zhang Jun;Jin Xian-Min;Feng Fa-Yong;Yang Bin;Yang Jian;Yin Juan;Zhang Qiang;Li Nan;Tian Bao-Li;Pan Jian-Wei
Physical Review Letters