1. Department of Physics East China University of Science and Technology Shanghai 200237 China
2. National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and Manipulation Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences Nanjing University Nanjing 210093 China
3. Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program Kent State University Kent OH 44242 USA