The Institute of Condensed State Physics;
Jilin Normal University;
Siping 136000;
P R. China;
Key Laboratory of Excited State Processes;
Changehun Institute of Optics;
Fine Mechanics and Physics Chinese Academy of Sciences;
Changehun 130033;
P R. China;
School of Material Science and Engineering;
Jiangsu University;
Zhenjiang 210013;
P. R. China;