1 South China University of Technology, School of Physics and Optoelectronics, Guangzhou, China
2 South China University of Technology, State Key Laboratory of Luminescent Materials, Guangzhou, China
3 South China University of Technology, Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices, Guangzhou, China
4 South China University of Technology, Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, Guangzhou, China
5 South China Normal University, Research Institute of Future Technology, Guangzhou, China