1. State Key Laboratory of Luminescent Materials and DevicesSchool of Materials Science and EngineeringSouth China University of Technology Guangzhou 510640 China
2. Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied TechniquesGuangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices Guangzhou 510640 China
3. Institute of Optoelectronic TechnologyChina Jiliang University Hangzhou 310018 China
4. College of Optical Science and EngineeringState Key Laboratory of Modern Optical InstrumentationZhejiang University Hangzhou 310027 China