1. Key Laboratory of Optical Communication Science and Technology of Shandong Province, School of Physical Science and Information Technology of Liaocheng University, Liaocheng 252059, China
2. State Key Laboratory of Superhard Materials and Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
3. Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, USA