1. Anhui Provincial Key Laboratory of Photonic Devices and Materials Anhui Institute of Optics and Fine Mechanics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei 230031 P. R. China
2. University of Science and Technology of China Hefei 230026 P. R. China
3. Advanced Laser Technology Laboratory of Anhui Province Hefei 230037 China
4. Science and Technology on Solid‐State Laser Laboratory Beijing 100015 P. R. China
5. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 P. R. China