1. Laboratory of Infrared Materials and Devices The Research Institute of Advanced Technologies Ningbo University Ningbo China
2. Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province Ningbo University Ningbo China
3. Laboratory of Glasses and Ceramics UMR 6226 CNRS‐University of Rennes 1 Rennes Cedex France
4. Department of Physics National University of Singapore Singapore City Singapore