1. Center for Optoelectronics Materials and Devices & Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, China
2. State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
3. State Key Laboratory of Information Photonics and Optical Communications & Laboratory of Information Functional Materials and Devices, School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China