[1] Shaanxi Univ Sci & Technol, Sch Arts & Sci, Dept Phys, Xian 710021, Peoples R China
[2] Shaanxi Univ Sci & Technol, Sch Elect & Control Engn, Xian 710021, Peoples R China
[3] Univ South Wales, Fac Comp Engn & Sci, Wireless & Optoelect Res & Innovat Ctr, Pontypridd CF37 1DL, M Glam, Wales
[4] Guilin Univ Elect Technol, Photon Res Ctr, Sch Optoelect Engn, Guilin 541004, Peoples R China
[5] Guilin Univ Elect Technol, Guangxi Key Lab Automat Detecting Technol & Instr, Guilin 541004, Peoples R China