(Anhui Institude of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, P. R. China; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China; Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, P. R. China)