1. The Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing, 100190, China
2. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
3. Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
4. Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China