1. Hunan Provincial Key Laboratory of Intelligent Information, Processing and Application, College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, Hunan 421002, China
2. Department of Physics, University of Texas at Dallas, Richardson, TX 75080-3021, USA
3. Patent Office of the State Intellectual Property Office, Beijing 100088, China
4. College of Physics and Engineering, Chengdu Normal University, Chengdu, Sichuan 611130, China
5. Department of Physics, Beijing Normal University, Beijing 100875, China