[1] Huainan Normal Univ, Dept Phys, Huainan 232001, Peoples R China
[2] Chinese Acad Sci, Anhui Inst Opt & Fine Mech, Hefei 230031, Anhui, Peoples R China
[3] Anhui Polytech Univ, Coll Elect Engn, Wuhu 241000, Peoples R China
[4] Anhui Inst Informat Technol, Gen Educ & Foreign Language Coll, Wuhu 241003, Peoples R China