1. Key Lab of Materials Physics Anhui Key Lab of Nanomaterials and Nanotechnology Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei 230031 P. R. China
2. University of Science and Technology of China Hefei 230026 P. R. China
3. Goldots Detection technology of Hefei Co. Ltd Hefei 230000 P. R. China
4. State Key Laboratory of Optical Technologies on Nano‐Fabrication and Micro‐Engineering Institute of Optics and Electronics Chinese Academy of Sciences Chengdu 610209 P. R. China