[1] Xian Modern Chem Res Inst, Xian 710065, Shaanxi, Peoples R China
[2] Nanjing Univ Posts & Telecommun, Inst Adv Mat, Nanjing 210003, Peoples R China
[3] Peking Univ, Dept Phys, State Key Lab Artificial Microstruct & Mesoscop P, Beijing 100871, Peoples R China
[4] Chinese Acad Sci, Xian Inst Opt & Precis Mech, State Key Lab Transient Opt & Photon, Xian 710119, Shaanxi, Peoples R China