作者机构:[1]National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China, [2]Laboratory of Quantum Opt-electronics, Southwest Jiaotong University, Chengdu 610031, China
相关基金:Project supported by the National Natural Science Foundation of China (Grant No. 10725415) and the State Key Program for Basic Research of China (Grant No. 2006CB921801).