1. College of Information Science and Engineering, Fujian Provincial Key Laboratory of Light Propagation and Transformation, Huaqiao University, Xiamen 361021, People’s Republic of China
2. Department of Physics, Jiujiang Research Institute, Xiamen University, Xiamen 361005, People’s Republic of China
3. State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, People’s Republic of China
4. Department of Mechanical Engineering, University of California at Berkeley, Berkeley, California 94720, USA