[Xiao, Weilai; Ling, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.
[Zhou, Lei; Ling, Xiaohui] Fudan Univ, State Key Lab Surface Phys, Key Lab Micro & Nano Photon Struct, Minist Educ, Shanghai 200433, Peoples R China.
[Zhou, Lei; Ling, Xiaohui] Fudan Univ, Phys Dept, Shanghai 200433, Peoples R China.
[Luo, Hailu; Chen, Shizhen] Hunan Univ, Sch Phys & Elect, Lab Spin Photon, Changsha 410082, Hunan, Peoples R China.
[Zhou, Xinxing] Hunan Normal Univ, Sch Phys & Elect, Synerget Innovat Ctr Quantum Effects & Applicat, Minist Educ,Key Lab Low Dimens Quantum Struct & Q, Changsha 410081, Peoples R China.