1. Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Siyuan Laboratory Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials Department of Physics Jinan University Guangzhou Guangdong 510632 P. R. China
2. Department of Mechanical and Materials Engineering University of Western Ontario London Ontario N6A 5B9 Canada
3. Instrumental Analysis & Research Center Sun Yat‐sen University Guangzhou Guangdong 510275 P. R. China