1. Research Center of Mathematics and Applied Mathematics and School of Mathematics and Physics, Nanyang Institute of Technology 1 , Nanyang 473004, China
2. School of Integrated Circuits, Huazhong University of Science and Technology 2 , Wuhan 430074, China
3. Shanghai Ultra-Precision Optical Manufacturing Engineering Center and Department of Optical Science and Engineering, Fudan University 3 , Shanghai 200433, China
4. Ames Laboratory, U. S. Department of Energy and Department of Physics and Astronomy, Iowa State University 4 , Ames, Iowa 50011, USA