1. Laboratory of Infrared Materials and Devices Research Institute of Advanced Technologies Ningbo University Ningbo 315211 P. R. China
2. Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province Ningbo University Ningbo 315211 P. R. China
3. Engineering Research Center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Province Ningbo University Ningbo 315211 P. R. China
4. Laser Physics Center Research School of Physics Australian National University Canberra ACT 2601 Australia
5. Science Program Texas A&M University at Qatar Doha 23874 Qatar