[Luo, Hailu; Chen, Shizhen] Hunan Univ, Sch Phys & Elect, Lab Spin Photon, Changsha 410082, 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.
[Ling, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.
[Shu, Weixing; Wen, Shuangchun] Hunan Univ, Sch Phys & Elect, Key Lab Micro Nanooptoelect Devices, Minist Educ, Changsha 410082, Peoples R China.