1. State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, and Guangdong Engineering Technology Research Center of Special Optical Fiber Materials and Devices, South China University of Technology, Guangzhou 51064, China
2. Faculty of Materials Science and Engineering, Yunnan Joint International Laboratory of Optoelectronic Materials and Devices, Kunming University of Science and Technology, Kunming 650093, China