1. Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems; School of Materials Science & Engineering; Beijing Institute of Technology; 5 Zhongguancun South Street Haidian District Beijing 100081 China
2. School of Optoelectronics; Beijing Institute of Technology; 5 Zhongguancun South Street Haidian District Beijing 100081 China
3. Micro Nano Technology Center; School of Physics; Beijing Institute of Technology; 5 Zhongguancun South Street Haidian District Beijing 100081 China