[1] Key Lab Quantum Informat & Quantum Optoelect Devi, Xian, Shaanxi, Peoples R China
[2] Xi An Jiao Tong Univ, Dept Appl Phys, Xian 710049, Shaanxi, Peoples R China
[3] Univ Sci & Technol China, Hefei Natl Lab Phys Sci Microscale, Hefei 230026, Anhui, Peoples R China
[4] Univ Sci & Technol China, Dept Modern Phys, Hefei 230026, Anhui, Peoples R China