1. Institute of Atomic and Molecular Physics and Functional Materials, School of Mathematics and Physics, Jinggangshan University, Ji'an, Jiangxi 343009, People's Republic of China
2. MOE Key Laboratory of Advanced Micro-Structure Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
3. College of Communication Engineering, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China