1. Laboratory of Infrared Material and Devices, The Research Institute of Advanced Technologies, College of Information Science and Engineering; Ningbo University; Ningbo 315211 China
2. Nanhu College; Jiaxing University; Jiaxing 314001 China
3. Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province; Ningbo 315211 China
4. Centre for Ultrahigh bandwidth Devices for Optical Systems, Laser Physics Centre, Research School of Physics and Engineering; The Australian National University; Canberra ACT 2600 Australia