1. State Key Laboratory of Modern Optical Instrumentation; Centre for Optical and Electromagnetic Research; Zhejiang University; Hangzhou 310058 China
2. Key Lab of Advanced Transducers and Intelligent Control System; Ministry of Education and Shanxi Province; College of Physics and Optoelectronics; Taiyuan University of Technology; Taiyuan 030024 China
3. Department of Physics; Hangzhou Normal University; Hangzhou 310012 China