1. Center for Advanced Laser Technology, Hebei University of Technology 1 , Tianjin 300401, China
2. Hebei Key Laboratory of Advanced Laser Technology and Equipment 2 , Tianjin 300401, China
3. Wuhan Raycus Co., Ltd. 3 , Wuhan 430223, China
4. Institute of Laser and Optoelectronics, School of Precision Instrument and Optoelectronics Engineering, Tianjin University 4 , Tianjin 300072, China