1. State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques Guangdong Engineering Technology Research and Development Centre of Special Optical Fibre Materials and Devices School of Materials Science and Engineering South China University of Technology Guangzhou 510641 China
2. Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China
3. School of Physics and Optoelectronics South China University of Technology Guangzhou 510641 China